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HAPUA

Guidelines for Minimizing Losses in Energy Delivery

(Final)

HAPUA Working Group No. 3: Distribution

April 2010

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Contents

Introduction

1 .

O v e r v i e w1.1 Scope1.2 Purpose

2 . Defini t ions3 . Loss Classification

4 Quantitative Analysis of Loss4.1 Technical Loss

4.2 Non-Technical Loss

5. Loss Targeting & Regulatory Regime

6.

Loss Reduction Measures 6.1Technical Loss Reduction Measures

6.2 Non-Technical Loss Reduction Measures

Annex A (informative) Case Study

Annex B (informative) Technical Modeling and Assumptions

Annex B-1: Guidelines for the Application and Approval of Caps on the Recoverable Rate ofDistribution System Loss (MERALCO, The Philippines)

Annex B-2: Loss Factor Calculation- B-2.1: PEA (Thailand) Loss Factor Coefficient Calculation- B-2.2: EVN (Viet Nam) Technical Losses and Non-Technical Loss Calculation

Annex C (informative) Loss Management Practices of HAPUA Members

Annex C-1: Distribution Losses in HAPUA members

- C-1.1 Technical Losses

- C-1.2 Non-Technical Losses

Annex C-2: Loss Management Practices

- C-2.1 Technical Losses Management Practice of PEA- C-2.2 Non-Technical Losses Management Practice of PEA

- C-2.3 HAPUA Member Accuracy Meter Check

Annex D (informative) Bibliography

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1.1 Scope

This guide will identify factors that contribute to energy losses evaluation and suggest appropriateenergy losses reduction measures in energy delivery in distribution system.

1.2 Purpose

The purpose of this guide is to establish the useful information for Non-Technical and Technical Lossesreduction management. The guide includes a common policy, strategy and best practice activities forminimizing losses in distribution systems.

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2. Definitions

Customer : Any person or entity supplied with electricity service under a contract with a Distributor.

Distribution System Losses or Total Losses : The energy input including those delivered to theDistribution System by the Transmission System, Embedded Generating Plants, other DistributionSystems, and User Systems with generating facilities minus the energy output (i.e., electricity deliveredto the Users of the Distribution System) for a specified billing period.

Distribution Utility : Any Electricity Cooperative, Private Corporation, government-owned utility, orexisting local government unit, which has an exclusive franchise to operate a Distribution System.

Energy : The integral of power with respect to time, measured in Watt-hour (Wh) or multiples thereof.

Energy Input . Energy delivered to the Distribution System by the Transmission System, EmbeddedGenerating Plants, other Distribution Systems, and User Systems with generating facilities.

Energy Output : Energy delivered to the Users of the Distribution System.

Load : An entity or electrical equipment that consumes electricity.

Load Loss : The electrical loss due to the resistance of conductors that varies with the square of theelectric current.

Load Model : The representation of electrical load in Load Flow simulations for the purpose ofcalculating Technical Losses.

Metering Equipment : The electrical measurement devices including instrument transformers, wiring,communications, and other auxiliary devices associated with metering.

Network Model : The equivalent electrical circuits that mathematically represent electrical systems(e.g., Distribution System) which for calculating electrical parameters or simulating its behavior or

performance. It consists of resistance and reactance of the electrical equipment, devices and conductors.

No-Load Loss : The fixed loss incurred in electrical equipment regardless of the loading level. Thisincludes the fixed loss dissipated in transformers, voltage regulators, capacitors, inductors and otherelectrical equipment.

Non-Technical Loss : The component of Distribution System Losses that is not related to the physicalcharacteristics and functions of the electrical system. It is caused primarily by human.. Non-TechnicalLoss includes the electricity loss due to pilferage, tampering of meters, erroneous meter reading and/or

billing, and unmetered customers, etc.

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Technical Loss : The component of Distribution System Losses that is inherent in the physical deliveryof electric energy including load loss and no-load loss.

Three-Phase Load Flow : The analytical tool that simulates the power flows in an unbalanced three- phase Distribution System.

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3. Loss Classification

Distribution System Losses or Total Losses in this guide shall be classified into 2 categories asfollows:

(1). Technical Losses(2). Non-Technical Losses

The Technical Losses is the component of Distribution System Losses that is inherent in the physicaldelivery of electricity. It includes the Load and No-Load (or Fixed) Losses in the following:

Group 1: Lines Loss which consists of(1) Primary Distribution Lines(2) Secondary Distribution Lines

Group 2: Distribution Transformer LossGroup 3: Loss of Other Equipment such as

(1)

Power capacitor(2) Voltage transformer and current transformer for energy measurement

The Non-Technical Losses is the component of Distribution System Losses that is not related to the physical characteristics and functions of the electrical System, and is caused primarily by human error,whether intentional or not. Non-Technical Loss includes the electricity lost due to pilferage, tamperingof meters, and erroneous meter reading and/or billing.

Distribution System Losses will be presented as this following figure.

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DistributionSyste m Lo sse s

Non- Tec hnica lLo sse s

Figure 2 : Loss Classification

Tec hnica lLo sse s

- Elec t ri c i ty the f t

- N o n - p a y m e n t b y

cus tomers

- Defec t ive Me te r ing

- Etc .

Line s, Tra nsform e rsand Other Equipm ent

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4. Quantitative Analysis of Loss

Distribution System Losses or Total Losses, in general , shall be computed as the net of all energyinputs and all energy outputs for a specified period. Energy outputs also include electricity which has to

be provided for public service obligation (PSO) and utility consumption.

4.1 Technical Losses

Technical Losses shall be the sum of the hourly load and no-load (or fixed) losses in all distributionequipment, devices and conductors.

In equation form, the Technical Loss shall be computed as follows:

Technical Losses = E [Load Losses in Lines Loss(Group 1)J + [Load and No-Load Losses ofTransformers Loss (Group 2)J (4.1)

In general, loss of other equipments (Group 3) can be negligible. However, some utilities may include

the loss of this group in the calculation for better accuracy.

4.1.1 Load Losses

Load Losses which includes line loss and transformer loss can be calculated by many methods. Ifutilities have an excellent data base which includes hourly load curves of each customers anddistribution system network configurations, hourly load Losses in lines loss can be calculated by

performing three phase load flow in every time period which depends on load curve data (one time period may be 15 minutes or 30 minutes or etc.).

If hourly load curves data of each customer are not available meanwhile feeder load data can be

prepared, Loss Factor Method may be more suitable for technical loss calculation.

Loss factor (or Load Loss Factor) is the ratio of average loss to the peak loss. It can be calculated byusing load factor as follows:

Loss Factor =A x (load factor) + B x (load factor) 2; A = 1-B (4.2)

Load Factor will be identified by load measurement. A typical value of A and B are 0.3 and 0.7[1 Buller F.H., C.A. Woodrow, Load Factor-Equivalent Hour Values Compared, Electr.World, vol.92, No. 2july 14, 1928, pp.59-60] respectively. The value of A and B depend on load characteristic andnetwork configuration. It may not be equally used for every system. A and B factors should be

performed for each type of system which may be classified by area type (such as urban, rural, orindustrial) or load density and line length.

The following table shows the other values of A and B (calculation for the values of A, B and LLF(Loss Factor) appeared in Annex B-2)

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Alternative equation: LLF = (4.3)

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Table 1: The typical values of A and B coefficient Case A BLine* 0.33 0.67Transformer** 0.2 0.8

*PEA research project [1]

** Tennessee Valley Public Power Association [2], Distribution System Loss Reduction Manual Project LR-1(Booth & Associates, Inc.Consulting Engineers, 1994)

If loss factor is already calculated, energy loss, due to load losses, will be quantified as follows:

Energy Loss (Load Losses) = Loss Factor x Peak Loss x Time Period (4.4)

Peak Loss and Load Factor Calculation:

Case 1: Load Losses of Lines

Line peak loss will be performed by three phase load flow calculation. Peak load data of each point in adistribution system for line losses calculation can be estimated by allocating a peak load (identified bymeasurement) of lines that is measured at substation. The load allocation depends on the size oftransformer.

Case 2 Load Losses of Transformer,

Peak loss will be calculated by,

Peak Loss of Transformer =

Full load loss (klf) x [Peak load (kVA) / Rated power of transformer (kVA)] 2 (4.5)

Most power transformers will be installed with power meter and load data will be recorded. In this case peak load and load factor information is easily to obtain. In case of distribution transformer, powermeter are usually not installed. Therefore peak load data can be supposed by using load data which arerecorded in the assumed peak load period. Energy delivered on distribution transformer will beidentified by energy records of every customer connected which can be found in billing system. Loadfactor will be calculated by

Load factor (Distribution transformer) = energy records of every customer connection / [Peak Load (kVA) x Time period of billing] (4.6)

4.1.2 Transformer No-Load Losses

Transformer No-Load Losses or Transformer Fixed Loss will be calculated in terms of energy asfollows:

Energy Loss (Transformer No-Load Losses) = No-Load Loss Specification x Time Period (4.7)

No-Load Loss Specification is No-Load Loss level indentified in transformer specification

To evaluate technical losses of interested areas, every network and equipment may be calculated.However, this approach cannot be possibly performed according to very large numbers of network andequipment. A sample of network and equipment will be selected for calculation to represent technical

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losses of the area. The sample selection criteria should be set carefully. Geographical data, load densityand network line length may be appropriate factors to be considered when setting selection criteria.

4.2 Non-technical Losses

Non-technical losses shall be the residual loss after subtracting the technical Loss from the TotalLosses.

Non-Technical Losses = Total Losses Technical Losses (4.8)

The errors of non-technical losses calculation from equation 4.7 consist of:

(1) Errors in accounting and record keeping that distort total losses calculation. The causes oftotal loss errors are (1) the difference of energy input collection period and energy output collection

period and (2) incorrect meter reading due to human errors. These errors can be mitigated by applyingAutomatic Meter Reading which automatically collect energy input and output information.

(2) Errors in technical losses computation . Some parts of technical losses may not be included intechnical losses calculation because they are (1) too complex to represent in mathematic model, forexample, leakage current of insulators, (2) too little and able to be negligible such as losses of energymeasurement instrument and (3) errors in technical information of the network.

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5. Loss Targeting & Regulatory Regime

5.1 Loss Targeting

As energy loss level is an important key to identify utilitys efficiency, loss targeting is one of the mostinteresting and important issues. Some regulators set loss target by benchmarking to utilities with lowloss level. Some will set by assigning utilities to identify loss level on their own. Both schemes howeverare based on past performance and the requirement by regulator/shareholder.

Although Benchmarking is a good concept for loss targeting, it can be misleading if the utilitiesselected for benchmarking are very different in characteristics, especially the proportion of electric saleat each voltage level and planning criteria. As such, this might not be a true comparison.

Loss targeting is recommended to be set separately for each voltage level as loss characteristics are

different at various voltage level. This makes it easier for auditing and management purposes.Moreover, different voltage level requires difference loss reduction measures.

Distributed Generation (DG) is another factor affecting loss level. DG will either improve or reduce thedistribution loss, depending on its capacity and the location of DG in the network.

Appropriate loss management plan is required to manage loss targeting correctly. Roadmap concept isone of the management tools to help utilities to create energy loss management plans [1]. Roadmapconsists of 4 major parts as follows:

1. Existing Loss Level .

The quantity of total losses and technical losses at each voltage level shall be evaluated.The non-technical losses can be calculated by using equation 4.7. The abnormal points and their causescan be identified by performing root cause analysis. The accuracy of loss calculation depends on theavailability of data and information.

2. Criteria of Loss Reduction Planning , which comprise budget, financial return of lossreduction project (internal rate of return, net present value or payback period).

There are many methodologies to manage the causes of losses. Loss reduction that is less costlycan be selected first. This measures will then be implemented until the funds allocated exceeds the

criteria. Financial returns for each loss reduction measure will be evaluated. Loss reduction measureswith financial returns that cannot meet the criteria will be rejected or suspended before developing theaction plan.

3. Action Plan , including lists of loss reduction projects, time schedule and responsible agencies. Action plan is based on selected loss reduction measures. Utilities shall assign tasks of loss reductionmeasures to each responsible agency and establish key performance indicator (KPI), agency

performance evaluation system, penalty and reward scheme for motivating assigned agencies.These agencies shall also implement the exact concept to their teams for effectively implementation.

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4. Expected results of each loss reduction project and Loss targeting of each period (A periodmay be one year). Loss target can be established by two approaches. The first approach is the bottomup approach when the ground staff develop their action plans. The second one is the top down approachwhere the regulator or executives of utilities set target for the utility. However, both approaches needaction plan to meet the target. In case Top-down approach, fund is usually provided sufficiently toachieve the target.

Roadmap will be revised periodically. The benefit of Loss Roadmap will help regulators to set upelectricity tariff criteria linked to loss performance to the benefit of utilities.

5.2 Regulatory Regime

The key success factors of loss control are

1. Setting appropriate target.2. Agencies that are responsible and act with integrity.

3. Have a loss performance evaluation system in place.

4. Setting up a rewards and penalties scheme.

To accomplish regulator target and maximize utility efficiency, rewards and penalties scheme will beset up to drive utility to improve loss level. Some regulators currently allow some part of energy loss to

be passed through electricity tariff. Therefore utilities are persuaded to keep energy loss level lowerthan the specified energy loss in electricity tariff structure in order to be more profitable. In the future,regulators will increasingly be more stringent to check on utilities by regularly reviewing losscompensation in electricity tariff structure.

In line with regulators intention, utility will encourage regional offices to implement loss reduction program. In general, loss reduction programs are related to many regional offices. Loss committees,which comprise representatives of all related units, are a good way to built up a strong cooperation foreffective implementation.

Funds provision is the key factor if the regulators/shareholders require loss level that is lower than itstechnical loss. The expected improvement will not occur if utilities are not allowed to invest on better orhigher quality equipment and smart devices for detecting abnormal energy usage. The criteria of lossreduction investment have to be considered directly by regulator or policy maker.

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6.1.2 Load Balancing

Load balancing is one of the low cost techniques for technical loss reduction because it does not requireadditional network equipment. It only requires load level and phasor information at each load point.

In case 3 phase 4 wires system, load balancing can reduce about 5%-23% of energy loss [2]. Thesignificant reduction occurs because neutral wire current is decreased. The loss reduction result of thistechnique can be shown as follows [ 1 ]

% Unbalance

Figure 3 : Unbalance load effect: 3 phase 4 wires system

In case 3 phase 3 wires system, load balance may not be reduce energy loss as much as 3 phase 4 wiresystem. Load balance will only distribute load current in this case. Result of loss reduction can beshown [ 1 ]

Figure 4 : Unbalance load effect: 3 phase 3 wires systemAs mentioned above, load balancing technique is the interesting loss reduction technique for 3 phase 4wire system. In general, the effect of load balancing is more obvious during the peak load period.Although this concept is simple and easy to perform, utility will not benefit much from this technique.

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To get more benefit from this technique, load information and processes of load balancing have to beconsidered. If customer can be categorized by using load characteristic, energy usage of each customeris a good choice to use for load balancing. In radial distribution system, load balancing shall be done atthe end of every lateral and energy loss of neutral wire in every lateral will decrease and utility will getmore benefit than only applied load balancing in the main line.

The main problem of load balancing is the lack of data, especially phasor information of customers.Some utility have to survey distribution network before execute this measure. This process will increaseresources and cost. However, as it is inevitable , the data collected has to be managed well. If databasesystem of this information is not shared and is inaccurate, new meters can be installed to capture thedata for load balancing but the cost will be extremely high. Geographicalll Information System (GIS)and sound database management may be required to overcome this.

6.1.3 Power Factor Improvement

In general, most of loads require reactive power which causes low power factor and high current in the

lines. Most of power factor improvement is capacitor installation that intends to compensate reactive power in power systems. The sizing and location of capacitor for loss minimization is the load point,eventhough there are many constraints to this.

Power factor improvement can be done by utility and customer. In many countries, large customerscontrol their power factor at purchasing point as required by regulation. If power factor of the customerviolate the regulation, utility will penalize (VAR-charge) that customer. The regulation of power factorwill be approved by regulator or the authority concerns.

For utility, there are two alternatives to improve power factor. The first one is to install capacitor at thesecondary side of distribution transformer. The purpose of this alternative is to reduce copper loss oftransformer. In general, the capacitor size for this is a fixed-type. The sizing of capacitor is dependenton transformer load characteristic which comprises load power factor and minimum load level. Thechosen size will compensate reactive power of minimum load level.

The second one is to install capacitor in distribution network. This is the Optimal Capacitor Placement(OPC) method. It is an optimization method and can be expressed as follows:

Objective function; Minimize {Total Cost = Energy loss Cost + Investment Cost} or

Maximize {Total Benefit = Energy loss reduction Gain Investment Cost}

Constraint; Subject to: Voltage level of all point shall not be exceeded the regulation

Power system modeling for optimal capacitor placement will be the same as load flow calculationexcept load profile is included in the calculation. It can be represented by daily load curve or loadduration curve. Load duration curve method is recommended because it is more simply and less timeconsuming. As the load level is fluctuated unpredictably, the benefit that can be derived from using thedaily load curve method will be minimal.

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for capacitor installation. Capacitor will be installed in the location which is given the minimum index.The index will be determined by the following methods:

1. Use Jacobian matrix, which is a component of Newton-Rapshon method of load flowcalculation. [2]

2. Compute loss reduction by simulating a capacitor installation in every available location. Thesize of capacitor for simulation may be chosen by using the smallest size of utility fixedcapacitor.

The fixed type capacitor will be firstly selected until it is no longer effective or when there is voltagelevel violation. The switched type will then be used. The flow chart of optimal capacitor placement is asfollows: (this flow chart is used for DigSlient Program)

Figure 5 : Optimal Capacitor Placement Flowchart [1]

The location of transformer will be chosen by using sensitivity index Ploss : k is the available location

a Qk

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6.1.4 Loss Specification Improvement

Significant loss reduction can be achieved by tightening the specification on losses reduction for majorequipments, especially power transformer and distribution transformer. No-load loss and Copper loss oftransformer can be specified more stringently but the equipment will inadvertently cost more.

In the case of cable, there are two main types of losses;Voltage dependent losses are dielectric losses and losses due to charging current. The use of cable withlow capacitance and cable made of higher quality materials will mitigate such losses. This can beachieved with tight specifications but it would inadvertently increase the cost.Current dependent losses are conductors and sheaths losses. Conductor losses are mainly caused byskin effect and proximity effect. Sheath losses are mainly due to circulating and eddy currents,especially when single core cable is being used and sheath is bonded at both ends. The use of Milikenconductor will reduce the skin effect for large conductor size. Losses due to proximity effect can bereduced by increasing the distance between cables and management of current flowing in parallelconductors. To reduce sheath losses, single core cable are either single point bonded or cross-bonded.The effect of eddy current can be reduced by increasing the phase separation .

However, before changing the specifications, cost benefit analysis should be carried out to weigh the benefits derived from loss reduction against the higher equipment cost.

6.2 Non-Technical Loss Reduction Measures

6.2.1 Causes of Non-Technical Loss (NTL)

NTL are more difficult to measure because these losses are often go unaccounted for by the systemoperators and thus have no recorded information. The most probable causes of NTL are:

Electricity theft Non-payment by customer Defective Metering

The most prominent forms of NTL are electricity theft and non-payment, which are thought to accountfor most, if not all, of NTL in power systems. However, the majority causes of Non-Technical Loss(NTL) can be grouped into four categories as shown below.

6.2.1.1 Illegal connection from distribution line

Unscrupulous customers extract energy illegally by bypassing the energy meter or by connecting wiresdirectly to the distribution lines. In certain areas, direct tapping of power by non-customers is widely

prevalent. This kind of power theft takes place mainly in domestic and agricultural sectors.Geographical remoteness, mass basis for theft, poor law enforcement capability and inaction on the partof utility contributes to this phenomenon. Direct theft can tarnish the image and reputation of thecompany as it reflects the ineffective handling of this issue by the distribution utility. It should betackled with the highest priority.

Illegal connections may be tapped: Overhead bare conductors Open junction boxes (in cable systems) Exposed connections/joints in service cables

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6.2.1.2 Meter Tampering

In addition to the factors discussed above, theft of electrical energy causes an increment in non-technical losses. Since it is often not possible to catch the offenders, the amount of energy loss cannot

be determined and resulting in revenue loss. Stolen energy is, therefore, considered as a part of losses.Theft by the existing customers through tampering of meters is a predominant cause of utility revenueloss. Almost all categories of customers are involved in power theft. However, priority should be givento high value service customers for more effective and immediate revenue recovery. There are manyingenious way for tampering meter. New methods are constantly being discovered as shown:

Spiders : Small holes are drilled into the meters and live spiders or spiders' eggs crammed intothem. The spiders' webs slow down the metering mechanism, giving a false reading.

Needles : Pins are inserted into a hole, slowing down the meter's recording wheel to give a flashreading or even a zero usage.

Magnets: Small magnets attached to the outside of the meter casing will stop the meter from

registering, or slow it down.

Chewing gum: Gum is often used to stop the meter completely but it is taken out just before themeter reading is taken.

Bypassing: this will be power sourced illegally from underground cables and overhead wires or by passing the neutral wires in meters.

Others :

Intentional burning of meters; Changing the sequence of terminal wiring; Tampering the seals of meters;- Disconnecting Neutral wires;

6.2.1.3 Defective Metering and Meter Reading Error

Non-technical losses are also caused by some deficiencies in the functioning of the utility such asdefective metering and meter reading error. These losses are not due to any deliberate action of thecustomers. They are due to internal shortcomings of the utility and, hence, are that much easier totackle. Some of these factors are given below

Inaccurate metering system installed on outgoing radial feeders and distributiontransformers (inaccurate meters can result in errors in loss assessment).

Slow or defective meters at customer premises. Errors in the CT/PT ratios (in case incorrect ratios are considered in billing). Errors in assessment of consumption by un-metered customers (like street lights, public

amenities, traffic lights etc.). Errors in computing provisional consumption for customers with defective meters or for

customers whose meters have not been read. Over burdened CT. Wrong readings and data frauds: In many utilities the meters readers were in

connivance with the customers to record lower reading than the actual readingregistered at the meter.

Stuck up meters. No readings was furnished by the meter reader, and at times, repeatedly. Constant nil consumption cases reported without any comment.

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Progressive readings recorded in disconnected services. No relation between the meter capacity and the load. Adoption of wrong multiplication factors (MF) for billing as the change in MF is not

intimated to the billing agency. Unintentional errors in meter reading. Intentional errors in meter reading (collusion by meter readers). Data punching errors. Data punching errors by data entry operators. Lack of validation checks. Lack of management summaries and exception reports on meter reading .

6.2.1.4 Tardy Billing and Poor Revenue Collection

In addition to the external factors mentioned above, non-technical losses are also caused by billing andcollection. These losses are due to internal shortcomings of the utility and, hence, are that much easierto tackle. Some of these factors are given below

Non payment by customers, where utili ty does not have a method for timely

disconnection. Lack of a system for carrying out regular (monthly) energy accounting to monitor

losses Energy accounting errors (by not following a scientific method for energy audits). Errors in raising the correct bill. Manipulation/changes made in meter reading at billing centers lack of a system to

assure integrity in data. Lack of system to ensure bills are delivered. Lack of system to trace defaulters including regular defaulters. Lack of system for timely disconnection. Care to be taken for reliable disconnection of supply (where to disconnect).

6.2.2 Measures for Non-Technical Loss ReductionThe measures for reducing Non-Technical losses depend on the factors that cause them and these will

be discussed separately.

6.2.2.1 Measures for Controlling Illegal Connection

6.2.2.1.1 Stopping Theft by Direct TappingVarious measures can be taken by the electricity supply authorities to stop theft of energy

by direct tapping as follows: Setting up of Vigilance Squads (where these have not been set up). Carrying out surprise inspections by Vigilance Squads.

Periodic inspection of low tension (LT) feeders by the special Vigilance Squads fortracing unauthorized customers and direct tapping from line. Prosecution proceedings against persons indulging in theft of energy to secure

convictions in the Court. Therefore, the materials, wire and equipment may be kept asevidence to be produced at the court hearing to prove the criminal offences.

Imposition of heavy fines on customers found guilty of committing theft of energy. Starting a drive for regularizing unauthorized connections and simplifying procedure for

new connections.

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6.2.2.1.2 Use of Insulated ConductorsUse of modern and effective equipment, like Aerial Bunched (AB) Cables/partial

insulated LT lines in theft prone areas along with high voltage distribution system can prove to be aneffective deterrent to theft. The insulated cables make it more difficult to tap energy. The AB cables can

be installed on the same poles used for street lighting and telecommunication circuits. This would saveconsiderable cost and also avoid associated problems of communication.

6.2.2.1.3 Public Relation and Awareness Campaigns by the Utility Some change in the value system of the society is also needed. The opinion makers and

social leaders should be involved to effectively tackle this massive social issue. Some amount of public relations work by the utility is needed to tackle this menace. It can

help in publisizing widely that the effect of theft will result in tariff increase for thegenuine customers, and also resulting in poor reliability and quality of supply such ashaving unreliable voltages, burnt appliances and failed transformers.

6.2.2.2 Measures for Controlling Meter TamperingThe following steps can be taken to reduce such non-technical losses:

The energy meter could be housed in a sealed box and made inaccessible to thecustomers.

Multi-core PVC cables could be used as service mains instead of single core wires. Severe penalties may be imposed for tampering. Theft of electricity should be publicized as a social and economic crime to make the

public awared and informed of the provisions in electricity laws in this regard. Extensive checking of metering accuracy and detection of tampering should be

undertaken. Customers meters should be re-located outside of the customer premises. Potential link should be provided inside the body of the energy meter rather than inside

the thermal cover. This prevents the potential link to be disconnected by the customer. Energy variation in consumption must be regularly checked for all categories of

customers and suspected cases should be kept under close scrutiny through specialchecking.

Strict control and monitoring of meter readers to prevent malpractice. There should be provision of swapping of duties between meter readers and ledger

clerks.

6.2.2.3 Measures for Reducing Defective Metering and Meter Reading ErrorSome methods to prevent non-technical losses due to defective metering and meter reading error aregiven below

Stringent installation procedures has to be spelt out clearly and in details indicating allthe required checks and tests to ensure all checks are strictly complied with and all testsare carried out accordingly during meter installation.

Use of electronic meters with tamper and load survey logging features for all categories ofcustomer.

Use of optical port for taking the reading for all categories of customers. Sealing of meters with seals and having proper seal management system. Installation of CTs/PTs in sealed boxes so that terminals are not exposed for tampering /

bypassing. Testing of the metering system as a whole to ensure accuracy. Ensuring accuracy in meter reading and billing activities by generating exception lists and

following up on exceptions.

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Carrying out regular energy audits covering the feeder and all end customers to ensurethat there is no revenue leakage beyond the permissible technical loss.

Having clearly visible and accessible seals that can be subjected to easy inspection Setting up standards/practices/ procedures that will reduce wrong meter reading Expert training for new meter readers Promoting the use of new reading technologies (Handhelds/AMR) Introduction of prepaid meters

In addition to these measures, non-working and defective meters should be identified and replaced.There are many existing services that are not installed with meters, these services should be installedwith meters immediately. Similarly, a large-scale drive is necessary for bringing all unauthorizedcustomers on to the rolls.

Besides, utilities should purchase adequate quantity of meters both for fresh services and forreplacement of the defective meters in the existing services. Metering facilities should be installed notonly for measuring the electricity sold to the customers but also for monitoring the energy consumptionat different voltage levels.

The electromechanical meters tend to get sluggish over a period of time. Old meters should be replacedin a phases and in a timely manner with high accuracy static meters, especially for high value servicescustomers and at places where the load varies substantially. Electromechanical meters should bereplaced with electronic meters having ultrasonic welding. CT meters should be adopted instead ofwhole current meters for LT high value services. Advanced metering technologies, viz. prepaidmetering and remote meter readers should also be used.

6.2.2.4 Meter InstallationMeter installations have often been considered as a low skill, labour oriented activity. The quality ofinstallations must be given due importance to guard against non-technical losses. The installation

practices should take into account various classifications of meters Type of meter: These cover meters of different accuracy classes used for residential,

commercial and industrial purpose. The different types of meters are as follows: single phase meters, 3 phase 4 wire Whole Current meters, 3 phase 4 wire CT connected meters, 3 phase meters for HT supplies (CT/PT connected meters), For the HT customers meter with tamper logging features should be used.

Nature of application: The metering applications can be categorized under the following broadheadings:

Tariff metering (for customers), Inter utility tariff metering, and

System metering (for feeders and DTs). Location of metersIt is important to recognize that different applications require different installation practices

and functional specifications for the meters. Mere focusing on the installation practices alone without proper functional specifications will not serve the purpose. The location of meters, i.e., type or nature ofsite where meters are to be installed is equally important, as installation practices differ as per thefollowing types of site:

Indoor Installations, Outdoor installations at/near transformers, and Outdoor installations on poles.

The major cause of loss of revenue has been due to improper installations practices that allowed

tampering of the metering systems. Certain installation practices to prevent this are given below

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A Visually Traceable and joint free incoming cable, or shrink wrapped sealed jointhelps to prevent tampering.

Have a clear and visible seals that can be easily accessible for inspection Mount the meter and CTs inside a box with a clear window, where the internal

terminations and connections cannot be accessed without breaking through the seal Ensuring height and location of the installation for easy readability of meters Locating meters in public domain an alternate location for the meter can be on the

poles from where service cables are laid. With this installation, the meters are positioned at a height in full public view. This makes tampering work such as bypassing the meter and direct connections difficult.

6.2.2.5 Measures for Reducing Tardy Billing and Poor Revenue CollectionCorrect billing and timely delivery of bills will go a long way in improving the collections. The normalcomplaints in the billing process are: non-receipt/ late receipt of bills, receipt of wrong bills, wrongreading/ status, table readings and wrong calculations. All these can be avoided by going forcomputerized spot billing as is already done in some countries. A thorough understanding by the

readers on the status of the meter is a main factor for the success of the system.Common billing software must be adopted to exercise meaningful control, for review, storage andretrieval of the customer database. Efforts have to be made to minimize the bill processing time. Bill

processing time is the average number of days that transpire from the meter read date until bill issuance.Monthly billing should be achieved for the convenience of the customer and also for psychologicalreasons. Stringent checks must be adopted in the billing process in order to plug the leaks. The billingdepartment should detect the majority of billing errors internally before a bill is issued (e.g., based on aconsumption reading that does not follow a customers billing history). This will greatly reduce theerrors.

In some Distribution Companies, bill delivery is problematic, particularly, in the zones where powertheft is prevalent. The utility must have an effective bill delivery system with penal clauses for non-delivery of bills.

The power distribution companies have a unique advantage of contacting millions of citizens at leastonce in a month. This should be utilized to the full advantage to explain the latest initiatives and seekthe customers support in their own interest and in the interest of the company.

In most power distribution utilities, delays in payments or non-payment are the major cause of non-technical loss. Collection effectiveness refers to the Distribution Companys ability to collect paymentin a timely manner against the bills it issues. Performance on this front is affected by the limitedutilitys recourse for non-payment and delayed payment and the inability to write-off bad debts ornegotiates payments with customers. The utilities should have a system where defaulters are short-listedimmediately after nonpayment within due date with amount and time, etc.

Special collection drives, coupled with intensive inspections, in the areas where the payment history is bad, brings positive results. For recovery of arrears, the utility should

list defaulting customers; send reminders / notices; initiate legal proceedings; and Resort to disconnection, if need be.

Enhanced customer convenience should be the guiding factor for smooth collections. This can be done by introducing multiple payment locations and not restricting them to a particular division/subdivision.Other steps that can be taken are:

Provision of additional counters, depending upon the crowd, having Flexible Timings. Providing comfort to customers, e.g., drinking water, toilet, sitting arrangement at

collection centers.

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Installation of electronic cash register machines for collection and counting cash. Drop box facilities and roping in more collection agencies to eliminate lengthy queues.

The following are summary of the measure to reduce the tardy billing and poor revenue collection Setting up standardised practices and procedures that will reduce inaccurate billing.

Introduce meter readings verification report from the billing system. Define meter estimation procedures. Setting up standards/practices/ procedures that will reduce meter estimations. (e.g. billing

system locks the account for more than three estimations). Introduce prepayment, AMR (Automatic Meter Reading). Disconnect where the premises cannot be accessed after two reminders. Setting up standards/practices/ procedures that will reduce delayed billing for new

customers. Introduce intelligent billing that will pick up all un-billed customers. Introduce door to door delivery service for bills. Setting up standards/practices/ procedures that will reduce cases of un-billed customers. Verify if all dormant customers/ accounts in the billing system are not supplied.

6.2.2.6 Additional MeasuresUtilities can adopt Management Information System (MIS) and carry out energy accounting and auditfor preventing non-technical losses.

De ve lo pm en t of MI S Effective use of Information Technology(IT) can play a major role in loss reduction and ensure

better management efficiency of distribution utilities. Distribution utilities should institute MIS foreffective monitoring and control. The reports that can be generated from MIS are given below:

Feeder-wise/Distribution Transformer-wise loss, this could be done through by installingmeter at the secondary side of transformer in order to detect NTL;

Equipment failure and interruption analyses for the feeder; Customer analyses (kWh/kW); Realization Index ($/kWh) for each category and feeder as a whole; Consumption rise or drop by more than 20%; Payment update; Day-wise and amount-wise payments received from the customers; Communication with banks regarding payments realized; Identifying the defaulters; Recovery of arrears; Listing of defaulting customers; Sending reminders/notices; and Disconnections due.

The asset and customer database of the Utilities often gets outdated over a period of time. It is therefore

necessary to keep the database updated on a regular basis. The outdated information of the customersuch as contract demand, multiplication factor (CT/PT) can be a source of error contributing to non-technical losses. The utility should also have past track records on customers tampering their meters.This information is available from the analysis of the meter. (MIS can be effectively used for this

purpose.) Energy Accounting and Auditing

To tackle losses effectively it is necessary to compute the losses accurately, identify high loss areas andsegregate these losses into losses due to commercial as well as technical factors. For this, utilitiesestablish an Energy Accounting System area-wise to establish the losses on a continuous basis.Experience in many parts of the world demonstrates that it is possible to reduce the non-technical lossesin a reasonably short period of time by carrying out energy audits, prioritizing the results and focusingon high loss areas. Energy accounting helps in devising a systematic plan for handling the non-technical

loss in the system and in finding out whether the purpose has been adequately served.

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Accounting and auditing in the electricity sector involves evolving procedures and checks to accountfor energy from the generating stations down to the customer level. In the present scenario, the focusshould be from grid substations at sub-transmission levels to supply power to customers at variousvoltage levels. The objective is to prepare an energy account so as to establish the energy input andquantum consumed by/billed to various categories of customers. This leads to identification of high

loss areas, which, in turn, would help in finetuning strategies and action plans to reduce losses. Theaccounting system should ensure that the energy made available at substation, distribution feeder,distribution transformer and units utilized by customers, respectively, are checked to ensure thedifferences is reasonable and within the permissible limits.

For proper energy accounting, metering equipment must be installed both at the sending and receivingends. This activity should cover review of the existing energy accounting system, replacement ofdefective meters and installation of meters at appropriate locations for proper energy accounting.Important services, feeders, distribution transformers and towns should be taken up for this exercise.

Installation audits are a short-term measure for preventing non-technical loss. These audits cover theinspection of the site and a detailed testing. Installation audits are needed to detect and correct any

problems that may have resulted from poor installation practice or by unscrupulous acts by thecustomers.

During the installation audits, aspects such as accuracy of the meters, accuracy of CTs and PTs, presentload on the meter, fuses, ferruling of wires, evidence of tampers, etc. are checked. In addition, theterminals are opened for inspection and the connections re-tightened. Thus, the installation audits alsocover the preventive maintenance aspects of meter installation.

The frequency of installation audits have to be determined objectively and appropriately based onobservations and conditions from the field and other data generated through energy audits. Typicallyinstallation audits need to be carried out at least annually for 3-phase or HV customers and at least oncein 3 years for single phase customers. Most Regulatory Commissions have already specified the

frequency for meter testing.

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Annex A (informative) Case Study

Case Study of PLN Bali

1. Introduction

The milestone of PLN Bali to become a World Class Service Company started in 2003 when the

management of PLN Bali realized that PLN Bali must have a long term vision i.e. to become aworld class services PLNs regional office by 2007. This vision was considered too optimistic andeven impossible to realize at that time considering that it was the first time that PLN regional officedeclared that they want to achieve a world class services. Nobody would have thought that suchvision was achievable.

PLN Bali started its mission by mapping out its performance and compared it to Hong KongElectric Company, which was considered as one of a World Class Company. One of criteria wasthe distribution losses must not exceed 7%. At 2003, distribution loss of PLN Bali was 12.14% and

by 2007, the distribution loss has gone down to 6.86% and it did not stop there. By July 2009, thedistribution loss has lowered further to 4.9%. The success of Bali has become a trigger for otherPLNs regional office to realize that such a low loss is achievable.

2. Major operational statisticsUnit 2003 2004 2005 2006 2007 2008

Rated capacity MW 550 550 550 550 580 580 peak loadno. ofcustomers

MW

customers

372

659,971

385

673,233

401

683,419

422

698,725

456

717,428

482

738,654

energy saleselectricitytariff

distributionloss

GWh

Rp/kWh

%

1,981

672

12.14

2,079

678

9.72

2,165

683

8.61

2,211

691

7.53

2,387

696

6.86

2,563

712

5.92

3. Strategy of Loss Minimization

Loss minimization strategy began with identifying source of losses in both technical and nontechnical losses. Technical losses depend on construction and configuration of distribution networkwhile non technical losses depend mainly on the accuracy of energy transaction point. In terms ofinvestment cost and time, minimizing technical losses require high investment and long period,while non technical losses incur lower cost and shorter period of time.

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Technical loss minimization started with strengthening distribution network through planning,construction, and operation and maintenance activities. At the same time, non technical lossminimization program was carried out by ensuring accuracy of meter and meter reading, andminimizing illegal tapping of supply.

Theoretically, distribution losses could easily be identified and managed. However, experienceshowed that one important factor as to why the loss came down very slowly was because people isnot awared of the significance of losses. Thats why one of the main strategies was to educate andto campaign against high losses. It was also realized that since the loss had become an importantKey Performance Indicator for Regional Office, loss reporting must be guided to reflect realcondition. Otherwise, the real loss could never be specified and people tended to report what theythought good enough to deliver. Once the reporting mechanism has been agreed, the lossmanagement could be monitored and evaluated periodically to reveal the real condition.

In line with the campaign to raise awareness on the importance of loss minimization, PLN Bali declared loss minimization action plan each quarter with branch office recognising the lossimprovement of each branch office and reward them through a simple ceremony. Branch offices areranked according to their loss level improvement for the award.

4. Loss minimization Activities

a) Technical Loss activities

No Activities unit 2004 2005 2006 2007 2008

1 Uprating MV line 150 mm2 Kms 15.6 218 65.2 138 64,64

2 Uprating LV line 3x70, 1x50 mm2 Kms 12.8 107 6 141 34

3 Extension of LV line with inline > 5 Kms 13.3 61 50.1 49 23,58

4 MV line reconfiguration Kms 0 37 8 7 15 New MV Line construction feeder 6 0 0 0 5

6 Replacement of inline BC >> TC 10-16 mm customers 17.079 3.375 0 1.225 0

7 Pressing connector MV/LV pts 59.076 12.00476.30 130 39.865

8 Pressing connector MV pts 0 1.299 92 0 3669 Pressing connector LV pts 0 430 4.250 0 4.187

10 Pressing connector inline pts 0 10.27571. 95 0 35.312

11 Poor bare conductor replacement kms 10,7 0 0 0 012 LBS Lost Contact maintenance s/s 0 194 32 0 0

No Activities unit 2004 2005 2006 2007 2008

1 Inserted s/s < 160 kVA s/s 114 169 57 169 1302 Trans load management s/s 60 0 0 0 343 Transf. load balancing s/s 21 210 48 51 84

4 Maintenance of main fuse Contact s/s 49 194 33 171 48

5 Maintenance of Fuse Holder s/s 0 592 33 100 486 Replacement of transf. Jointing s/s 0 116 0 0 0

7 Replacement of Inlet / Outlet cables s/s 0 79 189 0 0

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b) Non Technical loss activities and energy saving

Activities 2004 2005 2006 2007 2008 Saved Energy(MWH)

Illegal use of MV Customers - 1,530 2,550 - - 4,080 Illegal use of LVV Customers 11,667 9,431 11,992 10,224 6,682 49,996 Total 11,667 10,961 14,542 10,224 6,682 54,076 Ilegal public lighting 1,300 446 - - - 1,746 Meter reading corrections 3,240 3,021 1,501 - - 7,762 Multiply factor corrections 2,340 68 - - - 2,408 Meter validation 95 608 1,458 1,990 357 4,508 Stucked Meter 133 97 182 28 15 455 Replacement of LV CT 9 51 128 201 149 538 Replacement of MV CT 166 439 1,066 143 212 2,026

Total Saving 18,950 15,961 18,877 12,586 7,415 73,519

5. Conclusion

The success of PLN Bali Loss Minimization program shows that it takes full commitment frommanagement and all members to fight against loss. Once the awareness has been raised, themanagement set up strategic plan with monthly action plan which can be verified and monitoredregularly. It is important that the strategic plan is translated into action in a systematic manner anddivided into stages for ease of monitoring and evaluation.

Management must design reporting mechanism to ensure that the loss minimization progress wasreported periodically and accurately. The rewarding system was also carried out to encouragecompetition amongst Branch Offices as well as a updating of loss targeting declaration which isdone during regional office 3-monthly meeting.

After 5 years of implementation, the significance of loss minimization movement has beeninternalised into PLN Bali personnel. Now is the time to search for a new method of lossminimization program instead of continuing with the same method. By constantly looking for newmethod, it is expected that the continuous improvement spirit will be maintained and refreshed, soas to meet future challenges with confidence.

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Graph-3: Staging towards Vision 2012

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OrganizationalStructure

T : 5,50%

Honesty and Transparency Building

2009

HR and ITpreparedness

Declaration of Target & Program

T : 5,00%

Reporting Application

2010

Focused and measurabletarget

Standard Design and Material

T : 4,50%

Accuracy in Meter Reading

2011

Consistent andSustainable

Prioritizing low costand high impact

T : 4,00%

2012 OfDISTRIBUTION

VISION

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Annex B (informative) Technical modeling and assumptionsAnnex B-1: Guidelines for the application and approval of caps on the recoverable rate ofDistribution System Loss (MERALCO, The Philippines)

Distribution Network Models

For purpose of calculating the Technical Loss, the Distribution System shall be represented byDistribution Network Models that are appropriate for Three Phase Load Flow simulations. Allequipment, devices and conductors of the Distribution System shall be characterized to capture theunbalances due to equipment construction, installation configurations, and connection and due to theunbalanced loading. In addition, the models must capture the Load-Losses and No-Load (or Fixed)Losses of all Distribution System equipment, devices and conductors except for metering burdenswhich are estimated separately.

The Distribution System shall be modeled by an interconnected network represented by series and shuntimpedances and/or admittance-parameter network in which a common node is used as a reference as

illustrated in Figure A-1. Self and mutual impedance and/or admittances of each Distribution Systemelement (e.g., line, transformer, etc.) shall be included.

Line Mode

Overhead Sub-transmission and Primary Distribution Lines shall be represented by a three-phase pi ()equivalent network with the corresponding self and mutual impedances of the phase and groundconductors as shown in Figure A-2.

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The series self- and mutual-impedances of conductors are given by the Carson equations for the series parameters:

The shunt parameters consist of self- and mutual-capacitive reactance due to the voltages (potential)and electrical charges of the conductors and their images below the ground as illustrated in Figure A-3and can be obtained from the following equations:

If conductor w represents the overhead ground wire or grounded neutral wire, then v w is zero, and thematrix in equation (8) can be reduced using kron reduction technique and then inverted to obtain thefollowing self- and mutual-capacitance of the lines:

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The admittance parameters (Y) can be obtained from the inverse of the capacitive reactawhere w and f are frequencies in radians per second and cycles per second, respectively.

Underground and Submarine Cables shall be modeled similar to the overhead lines with considerationsto the self and mutual impedances of the core, sheath and armor conductors.

Secondary Distribution Lines and Service Drops are similarly modeled except for the shuntcapacitances and mutual reactance which may be neglected.

Transformer and Voltage Regulator Models

Transformer and Voltage Regulator Models shall be developed based on the structure of magneticcircuit and connections of the windings. The leakage (series) impedance and the magnetizing (shunt)admittance shall capture the self and mutual impedance or admittance parameters of the transformer orvoltage regulator coils.

Shunt Capacitors and Inductors

Shunt Capacitors shall be modeled as lumped loads that are connected to a Bus with either constantresistance and reactance or constant real and reactive power demand as illustrated in Figure A-4. Thereal component of the power represents the Fixed Losses in the capacitors while the reactive power isinjected into the Bus that is required for power quality improvement.

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Shunt Inductors shall be modeled as lumped impedance (i.e., series resistance and reactance) parameters that are connected to a Bus as shown in Figure A-5. The inherent resistance of the inductorshall account for the losses which vary with the square on the current drawn by the inductor.

Series Inductors shall be modeled as series impedance like a Distribution Line without the shuntcomponents and mutual reactances as illustrated in Figure A-6. The inherent resistance of the inductorshall account for the losses which vary with the square on the current through the inductor.

Typical Load Curves for different types of customers and customer monthly energy billing are the basicinput to the Load Models. The total energy consumed by each customer is convolved to the normalizedload curve for the type of customer to determine the hourly power demands as illustrated in Figure A-7.Power factor of the load are specified based on measurements or reasonable assumptions.

Figure A-8 shows the step-by step procedure of converting energy consumption (kWhr in one billingcycle) to 24-hourly kW demands. The real power demand P t for time t is obtained from the per unit(p.u.) demand P t divided by the total area under the normalized load curve. Another set of dataspecifying the hourly demand is the hourly power factor (pf t) to compute for the hourly reactive powerdemand (Q t). These real power and reactive power may be divided into three components to representconstant power, constant current and constant impedance loads if their coefficients are known. For

purposes of segregating Distribution System Losses, Constant P and Q load models shall be acceptable.

Figure A-9 shows the complete hourly real and reactive demand for a typical residential customer.

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Distribution Utility may develop more accurate load models by preparing as many load curves as possible through a load survey for each type or even sub-type of customers that can capture seasonalvariations. Also, different load curves may be used for weekdays and weekends.

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Annex B-2: Loss Factor Calculation

Annex B-2.1: PEA (Thailand) Loss Factor Coefficient Calculation

Table A: Load Measurement Data

Time I (A) I 2

0:00 100 100001:00 90 81002:00 85 72253:00 80 64004:00 70 49005:00 75 56256:00 90 8100

7:00 130 169008:00 160 256009:00 200 40000

10:00 190 3610011:00 190 3610012:00 185 3422513:00 180 3240014:00 190 3610015:00 195 3802516:00 185 3422517:00 180 3240018:00 190 3610019:00 190 3610020:00 195 3802521:00 190 3610022:00 160 2560023:00 120 14400

Total 3620 598750

Step 1# Calculate Load Factor (LF).

Load Factor = Y_ Load Current / ((Maximum Load Current) x 24)= 3620/(200 x 24) = 0.75 Step 2# Calculate Loss

Factor (LLF). Loss Factor = ( Y_ Load Current 2)/((MaximumLoad Current) 2x24)

= 598750/(200 x 24) = 0.62

Step 3# Calculate A and B coefficient by analyzing the loss factorequation.

Loss Factor = A x Load Factor + B x (Load Factor) 2 , A+B =1

0.62 = A x 0.75 + B x 075 2 = (1-B) x 0.75 + B x 0.5625

B = 0.69

A = 0.31

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Annex B-2.2: EVN (Viet Nam) Technical Loss and Non-Technical Loss Calculation

1. Background

Electrical Energy Losses - A A (kWh) are the losses incurred in the transfer of electricity over aTransmission and distribution network includes Technical loss - A AT (kWh) and non technical loss -A AC (kWh).

A AT Losses vary with line length and depends on the amount of power being transferred. Overall lossescan vary from year to year as they depend on factors such as network configuration, conductors,transformers, utilization level, load profile and power factor of the system (level of reactive powersupport), etc.

To implement losses mapping and bring out suitable measures to reduce power losses, annuallycalculate technical losses and non technical losses are very importance.

2 . Technical losses calculation There are two components oftechnical losses on a distribution network.

a. Load Losses: These losses depend on the electricity being supplied through the distribution network.These losses are proportional to the square of the current being supplied through the network equipmentsuch as sub-transmission, distribution and, LV lines and distribution transformers.

Load Losses are calculated on the relevant part of the network under peak demand condition usingPSS/ADEPT software. Peak Losses are modeled in PSS/ADEPT using peak demand measure orcalculate from daily load curve and energy consumption for each bus (i) in the network.

A feeder has n buses, operation in duration T (hrs), energy consumption is A (kWh) and max demand isP (kW). Load at each bus can be calculated as follows:

Pmax i = 3. U. I max . cos orPmax i = P . (A i /A)Qmax i = [ (P max / Cos T )2 - P max2 10.5S .S i = (P max i / Cos T )2 J

The result of load losses is collected from report using PSS/ADEPT.

Load losses of transformers can be calculated separate as follows:

Load Losses = (Losses at Rated MVA) x ( S max /SRated MVA )2 The load current is not constants which is vary as a function of times

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The energy losses are calculated:

The energy losses are calculated using Load Losses and appropriate Load Loss Factor (LLF) as follows:

Load Energy Losses (kWh) = Load Losses at Peak Demand (kW) x T (hrs) x LLF

LLF is load loss factor or load curve factor is calculated as follows:

LLF = 2 S i2

X 1

24

b. No-load Losses: These losses are fixed and do not depend on the load. These losses arise fromtransformers, capacitors etc.

The No-load Losses for transformers, capacitors are obtained from manufacturers data and test sheets.The associated energy losses are calculated as follows:

No-Load Energy Losses (kWh) = No-Load Losses (kW) x T (hrs)

c. Technical losses: These losses is included load losses and No-load loss and calculated as follows:

A AT (kWh) = Load Energy Losses (kWh) + No-Load Energy Losses (kWh)

Technical losses (%) A AT % = (AAT / A ) * 100%

3. Non technical losses

Total losses (%) A A % = [(A INrUT A OUTrUT )/A INrUT ] 100% = ( AA / A ) * 100%

Non technical losses (%) is calculated as follows A A C % = A A % - A A T %

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The methodology can show as the figure follows:

8 is disturbances cause by practical data and methodology so AA A % and AA A % are approximateresults but they are very valuable to bring out treatments power losses.

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Annex C (informative) Loss management practices of HAPUA member

Annex C-1: Distribution Losses in HAPUA member

Annex C-1.1 Technical Loss

PART A: Overview of Power System (2008)

Member Country Voltage Level(kV)

Max.Demand

(MW)

Gen.Capacity

(MW)

EnergyBuy

(GWh)

EnergySales

(GWh)

TotalSystem

Losses (%)

Brunei Darussalam

Cambodia230,115,22,

0.4/0.23 293 300 1618 1460 9.78%

Indonesia 500,275,150,70,20,

0.38/0.22 21,120 21,580 144,367 128,810 10.78

Lao P.D.R 115,35,34.5,25,22,12.7,0.4/0.23401 308.74 509.95 1,969.64 13.17%

500,275,132,33,22, HV: 2.17%Malaysia 11,6.6,0.415/0.23 14,007 19,722.6 - 90,650.2 MV and LV:8.69%

Myanmar 230/132/6633/11/6.6/0.4

1203 6621 6621.76 4847TL : 6.8%DL : 20%

1 15/ 69/ 34.5/ 13.8/ 4,790 - 29,623 26,873 9.28%The Philippines 13.2/ 6.24/ 4.8/ (Includes(MERALCO) 0.460/ 0.230 74GWh

own-use)

Singapore400,230,66,22,

6.6,0.4 5,946 10,493 41134 3

230, 7,584.42 - 43,604 42,002 3.14%

Thailand (MEA) 115,69,12,240.4/0.23

Thailand (PEA) 115,69,33,22,0.38/0.22 14,089.58 -95,540 91,145 4.66%

Vietnam 500/220/110,35,22,15,10,6, 0.38/0.2212,636 15,213 65,890 TL: 2.5%

DL: 6.7%

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Member Country Number of

CustomersEnergy Sales

(GWh) / Voltage levelCircuit Length

(km)Number

ofEmployees

Remark

Brunei DarussalamCambodia 324,069 MV=136

LV=1017

HV=265

MV=816LV=1,697

2,354

Indonesia 38,844,086 HV: 11,628MV: 44,875LV: 71,251

Total: 127,754

EHV: 5,874HV: 28,310MV: 261,163LV: 353,762

42,626 EHV: 500kV & 275

kVHV: 150kV & 70

kVLao P.D.R 629,213 HV: 1,861.62

MV: 12,653LV: 11,070.71

3,040

Malaysia 7,329,727 HV: 19, 552

circuit-kmMV & LV:548, 981 km

29,210

Myanmar 1,969,862 4847.03HV-969.42MV-1841.87LV-2035.85

HV-6140.47MV-20699.25LV-13591.95

14433

The Philippines(MERALCO)

4,570,646 115 kV: 184.52734.5 kV: 8,011.88013.8/13.2 kV: 167.943Below 13.2 kV: 17.053

460/230 V: 18,491.751Total: 26,873.155

15,606 ~ 6,000

Singapore 1.25 million 41134 Transmission:5800

Distribution:22600

1574

Thailand (MEA) 2,797,513 HV: 3,927MV: 19,304LV: 18,771Total 42,002

HV:42.84(230kV), 1,491

(115/69)MV: 15,600LV: 24,807

8,648

Thailand (PEA) 14,600,420 H.V: 20,419M.V: 40,782L.V: 26,506Total 87,707

(2007)

H.V: 8,701M.V: 289,328L.V: 450,424

27,521

Vietnam 11,876,913 EHV: 3455H.V:

220kV: 7988110kV: 11786MV: 124910LV: 142652

85000

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PART B: Please specify Equipment Specification related to Technical Losses Calculation

Utility Name : EDC ( Electricite Du Cambodge ), Cambodia

Power TransformerTransformer

Rating

(MVA)

kW Loss Short-circuitImpedance

(Percent at 75C)

No-loadloss

Load loss

at 75 C

22 kV50 39 200 10

Distribution Transformer: Three phase transformerTransformer

Rating(kVA)

Watt loss Short-circuit

Impedance(Percent at 75 C)

22 kVNo-load loss Load loss

50 230 1200 4100 300 1750 4160 420 2500 4250 600 3400 4320 650 4000 4400 780 4700 4630 1200 6300 4.5

1000 1400 10800 61250 2050 1500

1500 2300 170001600 2300 170002000 2700 22500

CapacitorCapacitor

Sizing(kVAR)

Watt LossNo-load loss Load loss

150 - 3W/kVAR200 - 3W/kVAR 275 - 3W/kVAR

288,75 - 3W/kVAR 412,12 - 3W/kVAR

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Utility Name: PT. PLN (PERSERO) INDONESIA


Rating(MVA)


(Percent at 75 C)No-load

lossLoad lossat 75 C

5 6 32 7.510 8.5 42 10153060

142338

75103220

1012.512.5


Rating(kVA)

Watt Loss Short-circuit

Impedance(Percent at 75 C)

No-load loss 20kV

Load loss at 75 C

NewStd OldStdNewStd OldStd25 75 75 425 425 450 125 150 800 800 4

100 210 300 1420 1600 4200 355 480 2350 2500 4250 420 600 2750 3000 4315 500 770 3250 3900 4400 595 930 3850 4600 4500 700 1100 4550 5500 4630 835 1300 5400 6500 4800 1000 1750 6850 9100 4,5

1000 1100 2300 8550 12100 5

1250 1400 2500 10600 15000 5,51600 1680 3000 13550 18100 62000 1990 3600 16900 21000 72500 2350 4000 21000 25000 7

Notes: New standard applied since 2009

Distribution Transformer: Single phase transformerTransformer

Rating

(kVA)

Watt LossShort- circuit

Impedance(Percent at

75 C)No-load loss

NewStd/OldStd

Load loss at 75C

NewStd/OldStd10 40/60 185/220 2,516 50 265/275 2,525 70/105 370/385 2,550 120/170 585/585 2,5

CapacitorCapacitor Sizing

(kVAR)Watt Loss

No-load loss Load loss300 NA NA600 NA NA

900 NA NA1500 NA NA

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Utility Name: Electricite Du Laos (EDL), Lao P.D.R


Rating

(MVA)


(Percent at 75C)No-loadloss

Load loss

at 75 C

18

1012.51620222530


Rating(kVA)

Watt Loss Short-circuitImpedance

(Percent at 75 C)No-load loss Load loss

at 75 C22 kV50 210 1,050 4

100 340 1,750 4160 480 2,350 4250 670 3,252 4315 900 3,900 4400 980 4,600 4500 1,150 5,500 4630 1,350 6,500 4800 1,600 11,000 6

1000 1,900 13,500 61500 2,800 19,800 62000 3,250 24,000 62500 3,700 28,200 6


Rating(kVA)

Watt Loss Short-circuit

Impedance(Percent at 75C)No-load loss

Load lossat 75 C

10 60 145 220 90 300 230 120 430 250 150 670 2.2

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Utility Name: TENAGA NASIONAL BERHAD, MALAYSIA

Power TransformerVoltage

(kV)Transformer

Rating(MVA)

No-load loss(at ratedvoltage)

kW Loss

Load loss

(at CMR)Auxiliary loss

(at CMR)

Short-circuitImpedance

(Percent at 75 C) atnominal tap

132/33 90 RM 17,070 RM 6,385 RM 11,219 13.5%132/11 30 RM 17,070 RM 6,385 RM 11,219 13.5%* CMR = Continuous Maximum Rating

MVA

33/11kV 11/33KV

No-loadloss (W)

Load lossat 75 C

(W)

Shortcircuit

Impedance

No- loadloss(W)

Loadloss at75 C(W)

Shortcircuit

Impedance

1.5 16500 1600 5 14500 2400 169002 - - - - - -

7.5 39000 9000 8 to 10 - - -12.5 80000 12000 8 to 10 - - -15 82000 12000 10 to 12 80000 12000 9200030 120000 15000 10 to 12 - - -

MVA

22/11kV 22/6.6kV

No-loadloss (W)

Loadloss at 75

C (W)

Shortcircuit

Impedance

No-loadloss(W)

Loadloss at75 C(W)

Shortcircuit

Impedance

1.5 - - - - - -

2 19500 2500 7.5 - - -7.5 47000 5000 42000 6000 9 to 10

12.5 80000 12000 75000 10000 9 to 1015 - - - - - -30 - - - - - -

Distribution Transformer

kVA

33/0.433kV 6.6/0.433kV and 11/0.433kV 22/0.433kVNo- loadloss(W)

Load lossat 75 C

(W)

Shortcircuit

Impedance

No- loadloss(W)

Loadloss at75 C(W)

Short circuit

Impedance

No- loadloss(W)

Loadloss at75 C(W)

Shortcircuit

Impedance100 1500 300

5.00

1500 300

4.75

1600 240

5.00300 4500 730 2800 600 4400 700500 7180 1020 4100 1000 7300 900750 9200 1385 6000 1200 9200 1200

1000 11850 1665 7000 1400 11700 1500

CapacitorCapacitor Sizing

(kVAR)Watt Loss

No-load loss Load loss160 at 525 V NA 2.33 kW

900 at 11 kV NA 122 kW

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Utility Name: Ministry of Electric Power No. 2, Myanmar

Power Transformer

Transformer

Rating (MVA)

kW Loss Short Circuit

Impedance

(Percent at 75C)

RemarkNo Load Loss Load Loss at 75C

10 9.8 72 10 Local

20 19.6 135 11 Local

30 20.3 30.0 143 175.5 12 12.5 Local

60Single(20 x 3)

19 20 100 111 18.81 Purchase

100

Single(33.33 x 3)

26 28 110 146 23.03 Purchase

Distribution Transformer

Transformer Rating

(kVA)

kW LossShort Circuit Impedance

(Percent at 75C) No Load Loss Load Loss at

75C11/6.6 kV 33 kV

50 230 230 1050 4.5

100 350 350 1750 4.5

160 500 500 2350 4.5

200 590 590 2850 4.5

250 700 3250 4.5

315 850 3900 4.5

400 950 4600 4.5

500 1100 5500 5

630 1300 6500 5

800 1500 9900 5.5

1000 1800 12500 6

1250 2100 14500 6.5

1500 2300 17500 6.5

2000 2900 22500 7

2500 3150 24000 7

3000 3800 28000 7

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Utility Name : MERALCO ( Manila Electric Company), The Philippines

Power transformers

MERALCO, currently, does not specify load loss and no-load loss limits for new power transformers,since these are evaluated based on Transformer Life-cycle or Total Owning Cost (TOC), which takes

into account not only the initial transformer cost but also the cost to operate and maintain thetransformer over its life with the energy costs associated with load and no-load transformer lossesconsidered as part of the operating costs. The TOC is composed of the purchase cost of the transformer

plus the cost of load and no-load losses over the expected life of the transformer. However,MERALCOs procurement policy specifies monetary penalties for transformers whose actual load andno-load losses exceed the values guaranteed by the winning bidder.MERALCOs requirement for short circuit impedance is 10% at OA rating and 85 C (ANSI standard).

Distribution transformersThe TOC methodology is also used when evaluating distribution transformers from different suppliers. However,maximum allowable total loss in percent of the transformer rated kVA are also set, as shown in the followingtables:

Pole-mounted distribution transformers

kVA RatingTotal loss in % of

transformer rated kVA

25 1.5037.5 1.5050 1.2075 1.20

100 1.20167 1.20250 1.00

333 1.00

Padmount distribution transformers

kVA RatingTotal loss in % of

transformer rated kVA

75 (1 ph) 1.2167 (1 ph) 1.2500 (3 ph) 1.0750 (3 ph) 1.01000 (3 ph) 1.01500 (3 ph) 1.0

2000 (3 ph) 1.0

Line capacitor banks (three-phase)Bank Size Voltage Level Watts Loss

1800 kVAR 34.5 kV --600 kVAR 13.8 kV and below --

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Utility Name: Metropolitan Electricity Authority (MEA), THAILAND

Power Transformer (230/69,115kV) Transformer

Rating

(MVA)


(Percent at 75C)No-loadloss

Load loss

at 75 C

180/240/300 160 210 >= 15.2Remark: Cooling loss 15 kW

Distribution Transformer: Three phase transformer (69,115/12,24kV)Transformer

Rating(MVA)



lossLoad loss

at 75 C30/40 20 75 10

36/48/60 20 85 12Remark: Cooling loss 3.5 kW

Distribution Transformer: Three phase transformer (12,24/0.4,0.23kV)Transformer

Rating(MVA)



lossLoad loss

at 75 C15 70 160 1.2 - 4.445 160 360 1.2 - 4.475 220 580 1.5 - 4.4

112.5 255 840 1.6 - 4.4150* 300 1,000 2.1 - 4.4225 420 1,530 3.2 - 4.4

300* 480 1,860 3.9 - 7.0500* 670 3,030 >= 6.5750* 840 4,370 >= 6.5

1,000* 1,000 6,400 >= 6.51,500 1,200 10,000 >= 6.5

Remark: * Typical ratings

Distribution Transformer: Single phase transformer

TransformerRating

(kVA)


(Percent at 75C)No-load loss

Load loss

at 75 C5 35 70 1.2 4.4

15 65 150 1.2 4.425 100 250 1.2 4.4

37.5 130 375 1.2 4.450 145 420 1.5 4.475 200 540 1.6 4.4

100 240 700 2.0 4.4167 320 1,170 2.0 4.4333 500 2,340 3.9 5.0

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Utility Name: Provincial Electricity Authority (PEA), THAILAND

Power Transformer Transformer

Rating(MVA)



loss

Load loss

at 75 C25 15 100 8.5%-9.5%50 25 150 15% @ 50 MVA

Distribution Transformer: Three phasetransformer

TransformerRating(kVA)



at 75 C22 kV 33 kV50* 160 170 950 4

100* 250 260 1550 4160* 360 370 2100 4250* 500 520 2950 4315 600 630 3500 4400 720 750 4150 4

500** 860 900 4950 6.5 or more630 1010 1050 5850 4800 1200 1270 9900 6

1000 1270 1300 12150 61250 1500 1530 14750 61500 1820 1850 17850 62000 2110 2140 21600 6

Remark: * Typical ratings* * Allow for high density area

Distribution Transformer: Single phasetransformer

TransformerRating

(kVA)



Load loss

at 75 C

10 60 145 2.020 90 300 2.0

30* 120 430 2.050 150 670 2.2

Remark: * Typical ratings

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Utility Name: EVN Vietnam (Distribution network)


RatingkW Loss Short-circuit

ImpedanceLoad loss

No-load (Percent at 75(MVA) loss at 75 C C)25 15 108 10-14%40 23 160 12-14%63 39 230 14-16%


Rating(kVA)



at 75 C22 kV 35 kV50 135 140 650 4

100 205 215 1250 4160 280 290 1940 4250 340 360 2600 4320 390 410 3330 4400 433 460 3810 4560 580 610 4810 4.5630 787 820 5570 4.5750 880 920 6920 6

1000 980 990 8550 61250 1020 1050 10690 61600 1300 1340 13680 620002500

15002870

1550-

1710021740

66


Rating

(kVA)



Load loss

at 75 C

10 - - -15 52 210 225 67 330 2

37.5 92 420 2

5075100

108148207

5709331403

2 4

CapacitorCapacitor

Sizing(kVAR)

Watt LossNo-load loss Load loss

100 8200 16300 21600 42900 63

1500 105

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PART C: Role of Planning Criteria related to Technical losses

Utility Name : EDC ( Electricite Du Cambodge ), Cambodia

1. Voltage Criteria (VoltVoltage Rating Normal Contingency

Min Max Min Max230000 215000 245000 205800 239000115000 107500 123000 115000 11900022000 20002 24000 21000 22500

380 360 424220 207 244 212 230

2. Distance & Loading Criteria

EquipmentsDistance

(km)Capacity(MVA)

Percentage LoadingNormal Contingency

HVLoop 93 300 80% 100%MVRadial 20 7 80% 100%LV 1 1.6 80% 100 %Power Transformer - - 80% 100%Distribution Transformer - - 80% 10 0%

3. Regulations related to Customer size connecting to Power network

L.V. connecting:M.V. connecting: > 80,000 kWh/monthH.V no connecting:

4. Typical L.V. conductor sizingAl 3x70 + 1x70 mm 2 Al3x150 + 1x70 mm 2 Al3x240 + 1x70 mm 2

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Utility Name: PT.PLN (Persero) Indonesia


Min Max Min Max500,000 - 5% + 5% - 5% + 5%150,000 -10% + 5% -10% + 5%70,000 -10% + 5% -10% + 5%20,000 -10% + 5% -10% + 5%

400 -10% + 5% -10% + 5%


Equipments Distance(km)

Capacity(MVA)


MV Lines (main feeders) 5 - 20 6 10 50 70 100MV Lines (laterals) 2 - 10 3 - 5 50 - 70 100LV Lines 0.25 - 0.7 0.14 0.2 50 - 70 100Distribution Transf. - 0.025 1.0 50 80 100Power Transf. - 10 60 70 140


HV connected customers (150 kV) : 30 MVA and above MV connected customers (20 kV) : 200 kVA and above, traction. LV connected customers (400/ 230 V) below 200 kVA

4. Typical L.V. conductor sizing: 50, 70, 95 mm 2 , Al twisted XLPE insulated cable

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Min Max Min Max115,000 111,550 118,450 103,500 126,50035,000 33,250 36,750 31,500 38,50034,500 32,775 36,225 31,050 37,95025,000 23,750 26,250 22,500 27,50022,000 20,900 23,100 19,800 24,20012,700 12,065 13,335 11,430 13,970

400 376 440 360 440230 207 243.8 207 253


Equipments Distance(km)

Capacity(MVA)


Radial SystemLoop Line System

M. V. System

Radial SystemLoop Line System

L. V. System

Power Transformer - - 80% rating 100% (no time limit)- - 120% (with in 4 hrs)

Distribution Transformer - - 85% rating 100% (no time limit)


4. Typical L.V. conductor sizing AAC25,AAC30, AAC50, AAC70,AAC120,AAC150

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Utility Name: TENAGA NASIONAL BERHAD, MALAYSIA1. Voltage Criteria (Volt)

Voltage Rating Normal Contingency

Min Max Min Max

500 000 -5% +10% -10% +10%275 000 -5% +10% -10% +10%132 000 -5% +10% -10% +10%33 000 -5% +5% -10% +10%22 000 -5% +5% -10% +10%11 000 -5% +5% -10% +10%6 600 -5% +5% -10% +10%4 00 -6% +10% -10% +10%


Equipments

Distance(km)

Capacity(MVA)

Percentage Loading

Normal Contingency

Transformer 11/0.4kVTransformer 33/0.4kVTransformer 22/0.4kV

100kVA -1000kVA

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Utility Name: Ministry of Electric Power No. 2, Myanmar

1. Voltage Criteria (Volt)

Voltage Rating Normal + 5 % Contingency

Min Max Min Max

230,000 218500 241500 180000 250000

132,000 125400 138600 103300 140000

66,000 62780 69300 51600 68000

33,000 31350 34650 26000 34000

11,000 10450 11550 8600 12000

6,600 6278 6930 5300 6900

400 360 440 130 440

3. Regulation related to Customer Side Connecting to power network

HV

MV connecting > 403919.2 MWh/month

LV

4. Typical L.V Conductor Size

- HDBC No. 8,6,4,2,1,1/0,2/0

- SC 60 mm 2, 100 mm 2

- U/G Cable 35/50/70/95/120/150/185/240/300 mm 2

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Utility Name: Manila Electric Company (MERALCO), The Philippines

1. Voltage Criteria (Volt)Voltage Rating Normal Contingency

Min Max Min Max

220,000 -5% +5% -10% +10%

110,000 -5% +5% -10% +10%

69,000 -5% +5% -10% +10%

34,500 -5% +5% -10% +10%

13,800 -5% +5% -10% +10%

480 -5% +5% -10% +10%

230 -5% +5% -10% +10%


Equipments

Distance(km)

Capacity(MVA)


H.V. System

Radial System -171 (110kV)108 (69kV) 90% Line rating 100% Line rating

Loop Line System-

343 (110kV) 108 (69kV) 90% Line rating 100% Line rating

M.V. System

Radial System- 32 (34.5kV)

13 (13.8kV)

70% Line rating (OH)

50% Line rating (UG)

90% Line rating (OH)

70% Line rating (UG) L. V. System - 0.17 (230V) 80% Line rating 130% Line rating

Power Transformer -

33 (115-13.8kV)50, 83 (115-34.5kV) 70% rating 100% (no time limit)

150, 300 (220-115kV)150 (220-69kV) 90% rating 100% (no time limit)

Distribution Transformer -.010,.025,.050,.075

(34.5kV-240V)(13.8kV-240V)

80% rating 130% (no time limit)


L.V. connecting: Demand < 2 MVAM.V. connecting: 2 MVA :5 Demand < 10 MVAH.V connecting: Demand > 10 MVA

4. Typical L.V. conductor sizing secondary line3/0 AWG ACSR

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Project No 11

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