1. INTRODUCTION TO K-2 & K-3 GRIDS 1.1 GRID DESCRIPTION 1.2 SAFETY-RELATED LOAD 1.3 ACCEPTANCE 2. OFFSITE POWER SYSTEMS 2.1 500kV Network 2.2 132kV Power System 2.3 LOAD FLOW STUDIES 3. AC POWER SYSTEMS 3.1 TYPE OF UNIT AUXILIARIES TO BE POWER SUPPLIED (GENERAL DESCRIPTION) 3.2 ELECTRICAL POWER SUPPLY FOR POWER STATION AUXILIARIES 3.3 DESCRIPTION OF THE 6.6KV DISTRIBUTION SWITCHBOARDS 3.4 380V SWITCHBOARD CONFIGURATION 3.5 ELECTRICAL POWER RESUPPLY DURING OUTAGE (ETR) 3.6 TRANSFER OF NORMAL ELECTRICAL POWER SUPPLIES AFTER FAULT DETECTION 3.7 EMERGENCY SUPPLY TO AUXILIARIES FROM ONSITE POWER SOURCES (DIESEL GENERATOR SETS) 3.8 TOTAL LOSS OF OFFSITE AND ONSITE ELECTRICAL POWER SUPPLIES ON A PLANT UNIT, RESUPPLY BY EMT AND EES SYSTEM 3.9 TESTS RELATIVE TO THE AC SYSTEMS 4. DC Power Supply Systems 4.1 CONFIGURATION AND OPERATION 4.2 SAFETY ANALYSIS OF DC POWER SYSTEM 5. Emergency Diesel Generator Set and Site Supplementary Power Supply Diesel Generator Set 5.1 THE SITE SUPPLEMENTARY POWER SUPPLY DIESEL GENERATOR SET (EMS) 5.2 INSTRUMENTATION, CONTROL AND PROTECTION RELATIVE TO EMERGENCY DIESEL GENERATOR SET 1
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1. INTRODUCTION TO K-2 & K-3 GRIDS
1.1 GRID DESCRIPTION
1.2 SAFETY-RELATED LOAD
1.3 ACCEPTANCE
2. OFFSITE POWER SYSTEMS
2.1 500kV Network
2.2 132kV Power System
2.3 LOAD FLOW STUDIES
3. AC POWER SYSTEMS
3.1 TYPE OF UNIT AUXILIARIES TO BE POWER SUPPLIED (GENERAL DESCRIPTION)
3.2 ELECTRICAL POWER SUPPLY FOR POWER STATION AUXILIARIES
3.3 DESCRIPTION OF THE 6.6KV DISTRIBUTION SWITCHBOARDS
3.4 380V SWITCHBOARD CONFIGURATION
3.5 ELECTRICAL POWER RESUPPLY DURING OUTAGE (ETR)
3.6 TRANSFER OF NORMAL ELECTRICAL POWER SUPPLIES AFTER FAULT DETECTION
3.7 EMERGENCY SUPPLY TO AUXILIARIES FROM ONSITE POWER SOURCES (DIESEL GENERATOR SETS)
3.8 TOTAL LOSS OF OFFSITE AND ONSITE ELECTRICAL POWER SUPPLIES ON A PLANT UNIT, RESUPPLY BY EMT AND EES SYSTEM
3.9 TESTS RELATIVE TO THE AC SYSTEMS
4. DC Power Supply Systems
4.1 CONFIGURATION AND OPERATION
4.2 SAFETY ANALYSIS OF DC POWER SYSTEM
5. Emergency Diesel Generator Set and Site Supplementary Power
Supply Diesel Generator Set
5.1 THE SITE SUPPLEMENTARY POWER SUPPLY DIESEL GENERATOR SET (EMS)
5.2 INSTRUMENTATION, CONTROL AND PROTECTION RELATIVE TO EMERGENCY DIESEL GENERATOR SET
5.3 VITAL INSTRUMENTATION AND CONTROL POWER SUPPLY
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1.INTRODUCTION TO K-2 & K-3 GRIDS
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1.1 GRID DESCRIPTION
The new Karachi Nuclear Power Plant (K-2/K-3) will be constructed at site located
near K-1, in the southern coastal region of Pakistan on Arabian Sea.
The power plant is connected with two different power sources:
i. 500kV for the power transmission and normal plant startup or shutdown.
ii. 132kV for the auxiliary supplies of the auxiliaries necessary for shutdown and
safety.
These two plants will deliver the generated power to WAPDA system through a common
switchyard (for K-2 and K-3), connected to Matiari grid by two 500kV double circuit
transmission lines.
The following interconnection scheme has been proposed for reliable dispersal of power
from future coastal power projects (K-2 & K-3) to the National Grid System under normal
and single line contingency conditions:
i. Two 500kV HVAC D/C transmission lines, approx. 200 + 200 =400 km long, on
twin bundled Greeley conductor from K-2/K-3 power plants to Matiari;
ii. ±600 kV H\TDC bipole (2x 2000 MW capacity), approx. 1000 km long, on six
bundle Bitterroot conductor from Matiari to Lahore South with HVDC convertor
station on both ends.
It is important to highlight that the interconnection of 1200 MW imported coal plant, lying
in coastal area nearby, has been proposed in one of the four 500kV circuits from K-2/K-3
power plant to Matiari.
Gross and Net Capacity of proposed Coal Plants
The gross and net capacity of these projects is given as under:
i. Gaddani Imported Coal project (Gross Capacity: 5x1320 = 6600 MW & Net
Capacity: 5x1200 MW = 6000 MW);
ii. Bin Qasim Imported Coal Project (Gross Capacity: 1320 MW & Net Capacity:1200
MW);
iii. Jamshoro Coal fired project (Gross Capacity: 1320 MW & Net Capacity:
1200MW);
iv. Thar Coal project (Net Capacity: 1200 MW);
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v. Maximum generation of the existing thermal power plants at Hubco, Jamshoro,
Kotri, Uch- 1, Uch-2 and Guddu power plant in south;
vi. Wind power plants generation with total gross capacity of 1756 MW in the
southern part of the system. The wind power has been planned to be evacuated to
the 132kV and 220kV network underneath Jamshoro. 8.1.2 Onsite Power Supply
Three sources of offsite power are provided to supply preferred power to the onsite
Class 1E systems through 500kV switching station and 132kV auxiliary switching station.
The main features of the distribution network are as follows:
i. The generator circuit breaker connections between the generator and the main
transformer enables to cut off fault current.
ii. The auxiliaries for each Unit are divided into groups depending on their safety and
operational function, including consideration of all the different operational
situations and foreseeable abnormal situations.
iii. The two Units are electrically independent. In case of an accident, the faulty Unit
must be able to respond to the accident regardless of the condition of the other Unit.
For this reason, each Unit has two independent diesel generator sets.
1.2 SAFETY-RELATED LOAD
Power supplies to the auxiliaries are designed to meet requirement of Unit availability
and, more importantly, of nuclear safety. Nuclear safety depends upon various factors on
the electric supply conditions of certain auxillary systems of NSSS.
The design of the electric power system has following features.
i. Electric power sources
The electric sources include two offsite power sources separately routed from the
main grid with common routing near the power plant due to the geographical
arrangement. Two onsite sources consisting of 100% redundant diesel generator
sets.
ii. Electric power supplies
The electric power supply system consists of two identical trains. These trains are
independent and are normally supplied by one of the offsite sources (the second source
ensures redundancy) and are backed up by the onsite sources in the event of main grid
failure.
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1.3 ACCEPTANCE
Power supplies have been designed based on the following criteria:
- They comprise two physically independent systems (not necessarily separately
routed) to ensure that simultaneous failure is minimized.
- The 132kV auxiliary power source is supplied by substation nearby;
- The quality of both sources is such that the auxiliaries supplied can be operated
or be started as soon as they are transferred from one source to the other.
- One supply for each of the two safeguard trains;
- No interconnections between trains of separate Units;
- Each power train supplies the electrical auxiliaries of each independent train of
the redundant mechanical systems (physical separation), so that loss of one
train does not lead to a loss of functions.
References
[1] HAP 102-2004, Safety Code on Nuclear Power Plant Design
RCC-E Design and Construction Rules for Electrical Components of nuclear Island
2.OFFSITE POWER SYSTEMS
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The Nuclear power plants (K-2/K-3) will be connected with two independent offsite power
sources, one at 500kV and other at 132kV in National Transmission and Dispatch Company
(NTDC) and Karachi Electric Supply Corporation (KESC) System respectively.
Each Unit (K-2/K-3) will generate power at 24kV and this power will be stepped-up to
500kV by the Main Transformers (MTs) independently. The 500kV network will also
supply power for normal plant startup or shutdown.
The 132kV network will be used as a standby power supply source.
2.1 500kV Network
The power generated by the plants (K-2/K-3) will be delivered to NTDC System through a
500kV switchyard (common for K-2 and K-3), connected via two 500kV double circuit
transmission lines from K-2/K-3 to Matiari.
For dispersal of power from K-2/K-3, 3x500kV circuits to Matiari will be installed, which is
about 200 km from plant site and lx 500kV circuit for looping in and out on Bin Qasim
Power Project which is about 140 km from plant site will be installed. The 500kV
electrical system is classified as Non-Class 1 E System.
The 500kV system constitutes a preferred source (offsite) for supplying power to plants
auxiliaries including Class 1E loads. The system will supply electrical power for start up,
safe shut-down as well as operation of emergency systems and the engineered safety features,
in accordance with IEEE 765-2006 standard.
The 500kV transmission lines from Matiari and Bin Qasim Power Project, and the 132kV
system will be physically separate and independent from each other, and designed in such a
way that the probability of simultaneous faults in the offsite power supply circuits (500kV
and 132kV system), due to operating conditions, postulated accidents and atmospheric
conditions is reduced to minimum.
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The 500kV system will supply power for start-up, emergency reactor shut-down,
containment isolation, reactor core cooling, and containment and reactor heat removal and all
those services required for preventing significant release of radioactive material to the
environment in accordance with IEEE 765-2006 and GB/T 13177-2008 standard.
The 500kV system will be provided with the instrumentation necessary for the
indication and continuous monitoring of its operational status, to ensure that any change in
the system, which could impair its functions is detected by the operator in the control room
in accordance with IEEE 765-2006.
All the circuit breakers of the 500kV system will operate manually/automatically from the
grid control building of K-2/K-3.All the components of the 500kV system will be designed
and installed in accordance with the requirements of latest applicable IEEE/ANSI, IEC and
other applicable standards .The limiting conditions for operation (LCOs) will be met in
accordance with USNRC Regulatory Guide 1.93-2012.
2.2 132kV Power System
The 132kV power system will act as a standby offsite power source and provide power
to the required plant emergency loads for safe shut-down of the plant(s) in case of
unavailability of 500kV network and outage of main generator(s).
The 132kV power system is classified as Non Class-i E System .The system will be
designed to be available within a few seconds following a loss of coolant accident to assure
that the core cooling, containment integrity and other vital safety functions are maintained.
The 132kV system will be designed to facilitate the periodic inspection and testing of
important areas and features - such as wiring, insulation, connections and switchboards to
assess the continuity of the systems and the condition of their components in accordance
with 1 OCFR5O Appendix A, General Design Criteria No. 18.
The 132kV power system will have sufficient capacity to provide the required loads during
start-up and the normal operation of the plant .A 500kV switchyard will be constructed
with all the required auxiliaries for dispersal of power from Units K-2/K-3 to Matiari and
Bin Qasim Power Project as shown in Figure.
The criterion of operation is as under:
a) Voltage Limits: ±5% under normal and ±10% under contingency conditions.
b) Transmission: 100% under normal and N-i contingency line loading conditions
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2.3 LOAD FLOW STUDIES
2.3.1 Peak Load January 2021
Load flow study for the peak load of January 2021 under normal system condition has been
carried out with the induction of 2x 1100 MW, K-2 and K-3 nuclear power plants and is
attached as Exhibit #1. As per load flow study, the power flows on the circuits emanating
from K-2/K-3 plants and in their vicinity are as under: