Introduction about Power System Planning in the Presence of Uncertainties

Introduction about Uncertainties

Power System Planning in Presence of

Uncertainties

Content :

is a term used in subtly different ways in a number of

fields, including physics statistics economics engineering

and information science. It applies to predictions of future

events, to physical measurements that are already made, or

to the unknown. Uncertainty arises in partially observable

on different environments,

Introduction Uncertainty

1.Measurement of Uncertainty: A set of possible states or outcomes where

probabilities are assigned to each possible state or outcome – this also

includes the application of a probability density function to continuous

variable

2.Measurement of Risk: A set of measured uncertainties where some

possible outcomes are losses, and the magnitudes of those losses – this also

includes loss functions over continuous variables

Uncertainty in Calculations

to determine the uncertainty for a quantity that was calculated from

one or more measurements ,There are complicated and less

complicated methods of doing this.

The simple one The Upper-Lower Bounds method of uncertainty in

calculations is not as formally correct, but will do. The basic idea of this

method is to use the uncertainty ranges of each variable to calculate

the maximum and minimum values of the function.

measurement = best estimate ±

uncertainty

the area would be:

A = l * w = 1.2 * 1.3 = 1.56 m^2

Area Presence of Uncertainties

The minimum area would be using the "minimum" measurements so

l = 1.2 - 0.2 = 1.0

w = 1.3 - 0.3 = 1.0

So the "minimum' area is A-min = 1.0 * 1.0 = 1.0 m^2

Likewise for the maximum area, l = 1.2 + 0.2 = 1.4 and

w = 1.3 + 0.3 = 1.6

So the Maximum area is A-max = 1.4 * 1.6 = 2.24 m^2

We can say ¥ = ±(0.2)(0.3) = 0.6 the area is A = 1.5 +/- 0.6 m^2 

For example you want to find the area of a square and measure one side as a length of 1.2 +/-

0.2 m and the other length as 1.3 +/- 0.3 meters,

power system planning namely,

• Base on Load forecasting (LF)

• Generations expansions planning (GEP)

• Substations expansion planning( SEP,)

• Network expansion planning (NEP)

• Reactive power planning (RPP)

We assumed, implicitly, that all decisions are made by a single entity

and the information used lacks any uncertainty. None of the above is

strictly true.

If Generations expansions planning is decided by some entities

based on the other entities cannot proceed towards the other

steps (SEP, NEP and RPP) if they cannot make sure what the GEP

players do in actual life. Still, there are more uncertainties

involved for their various decision makings .

The uncertainties play major roles in power system planning

issues of the new environment.

Power System regulating industry

In the regulated industry, power system structure consists of

generation, trans mission and distribution owned by a single entity;or owned by

different owners, controlled or regulated by a single entity.

the single entity decides on where and how to allocate generation and/or

transmission facilities. The investment and the operational costs as well as an

appropriate level of profit for the owners are compensated by regulated tariffs

imposed on the customers.

Power system in de-regulated In de-regulated environment,

The electricity is provided by some suppliers known as generation companies (

Gen.Co)$

The customers may wish to buy this commodity either from the high voltage or

low voltage (through distribution companies also called (Dis.Cos),may be

Owned by transmission company

electricity should be transferred from the suppliers to the customers through

the available transmission facilities (transmission lines and/or cables, ) That

owned by the transmission company and also called (TransCo)

The other facilities have to be owned investments or (owned

by the transmutation companies (TransCo ) is still fully or

partially

The electricity price is determined based on by suppliers from

one side and customer from other

de-regulated environment,

Generation company

Transmission line company

Distribution company

customers

Reactive power

Two terms of uncertainty and risk are widely used in power system planning

. There are no fixed definitions for these terms. Some believe that they are

the same, while some believe one is the result of another. Still, some think

of these to be quite independent..

we assume that the uncertainties involved may result in risk. For instance,

as GEP, SEP and NEP are based on the forecasted load,

any uncertainty in the forecasted load may result in risk so that the

network planned may be unable to fulfill its functions properly to supply all

loads

On the other hand, the uncertainties affect all short- power system

planning and long- power system planning deci sions.

Power System Uncertainties

1 Uncertainties module in a Regulated Environment power system planning is depend on load fore casting (LF)

and consists of GEP, SEP, NEP and RPP, input parameters.

The studies are to be carried out for some years in the

future depended on historical information so the input

parameters should be, accordingly, predicted

these parameters are in turn, dependent upon some other

parameters. As a result,

the input parameters to power system planning modules

may face uncertainties which obviously affect our decisions

Power planning modules input parameters are

Economic growth load forecasting (LF)

Economic parameters, such as inflation, depreciation and interest rates of

• Load forecasting (LF)

• Generations expansions planning (GEP)

• Substations expansion planning( SEP,)

• Network expansion planning (NEP)

• Reactive power planning (RPP)

• The Fuel cost (directly on GEP and indirectly on SEP, NEP and RPP

Technological developments (LF, GEP, SEP, NEP and RPP)

Environmental limitations (directly or indirectly)

Investment costs (GEP, SEP, NEP and RPP)

Demand side management programs (LF)

Operation and maintenance costs (GEP, SEP, NEP and RPP)

Resource (such as fuel and water,) availability (GEP)

Mane company or entity

trans mission line

Generations Distribution

regulated environment

2-Uncertainties module in De-regulated Environment

The power system de-regulating has resulted in appearing new independent

entities such as (GenCos, TmnsCos, DisCos,.)

The single-player environment has replaced by a multi-player, with its

risks and uncertainties involved.

each aiming at making, the maximum profit (revenues minus costs) from

its properties.

The de-regulation of the power industry leads to separation of the

transmission planning from the generation expansions. This will increase

the uncertainties and challenges

Each entity now should make its own decisions. And how to behaviors

with the other players into consideration in this new situation,

The electricity price is determined based on the supply-demand rule.

We discuss differentiate between the uncertainties involved in GEP

from one side and, TEP) from the other side.

Uncertainties in Generations expansions planning GEP This uncertainty introduced for the regulated environment, as

an owner should now make its own decision in investing on a

power plant, it new uncertainties.

The electricity price is the most important If investor may

invest in a location with an anticipated high electric price.

However, the behaviors of the other players should also be

predicted and taken into account. This prediction is not an easy task

at all

uncertainties more effects in the de-regulated environment For example ,

the costs of primary resources (such as gas, oil, etc.) may make an owner

to defer its investment in a place or changes its decision and invests in

another place.

In a regulated environment, although these costs are still effective, the

investor may still invest at the same place and time; as the money is

guaranteed to be back by some appropriate tariffs.

Uncertainties in transmission line expansion

planning TEP• This uncertainties in a regulated environment,

• Deal with how transmission line expansion planning may be properly

performed

• the most important uncertain factor which influences TEP ,the

uncertain GEP output.

• If GEP is decided upon by the other market players As the costs of

TEP should be recovered from the market par ticipants (both the

suppliers and the customers)

• an over design may result in players dissatisfactions or uneconomic decision .

• Under design can result in similar effects as the suppliers may be unable to sell

or cover the loads of the customers

Advanced of calculate Uncertainties in power planning

Reduced the risk and error

more accuracy Measurements for planning

Give robust power planning

Give more reliably for power system for short and long planning

Thank for listing

Reference1- Hossein Seifi • Mohammad Sadegh Sepasian electric power planning Issues, Algorithms

and solution chapter 11 section 11:1 -11:4

2- http://www.ivsl.org/?language=en