Azura-Edo Independent Power Plant Environmental Impact ... - IFC

• Emission levels of NOx at 20ppm, and CO at 30ppm (see Section 3.2.12).
High Voltage Switchgear
The dimensions of the high voltage switchyard are based on 330 kV air
insulated switchgear, with an arrangement of one bus section breaker and two
bus coupler breakers. The configuration allows for six incoming overhead line
circuits from the power plant ie four from the four OCGT gas turbine
generator transformers and two from the future steam turbine generator
transformers. There will also be two outgoing overhead line circuits.
3.2.4 Generator Specifications
The exact type of generator will be determined in the detailed negotiations
with the EPC contractor and will be subject to a competitive bidding process.
The generator rating would be 112.500 MW (140.625 MVA) with a terminal
voltage of 15 kV, a rated voltage of 50 Hz and a rated speed of 3000 RPM. The
rated power factor will be 0.8 (lagging) and the generator efficiency between
98.5 to 98.8 percent depending on the unit load. Each generator will have
automatic voltage regulator and a turbine speed control governor. A totally
enclosed water-to-air cooling system will be used with re-cooling by air-water
(fin fan) heat exchangers. The generators shall be equipped with a protection
scheme to protect and prevent damage to the plant.
3.2.5 Electricity Distribution from the Power Plant
The OCGT power plant will have four transformers that will step up the
voltage from 15 kV, at the gas turbine generator terminals, to the transmission
voltage of 330 kV. Electricity will then be fed over a short length of overhead
cable to an air-insulated switchyard before being exported via overhead cables
on a single tower or by underground cable, to the major new substation at
Benin North.
The switchyard will consist of circuit breakers and other high voltage
electrical equipment together with associated supporting steel structures.
At the substation there will be at least two main busbars where SF 6 (sulfur
hexaflouride) is used. The SF 6 is used to extinguish the arc caused when a
circuit breaker is opened, either by a control switch or due to a fault.
Disconnectors or isolating switches (manually or automatically operated) are
included on either side of each circuit breaker to allow for electrical isolation
during maintenance work.
The electricity will then flow either onto the National Grid or via the Benin
North 330/132 kV transformers or the Benin North 132/33kV transformers
into Benin City and surroundings.
The Project intends to contract for the supply of power at the national level.
Azura Power is currently negotiating a Power Purchase Agreement (PPA)
with the Nigerian Bulk Electricity Trading PLC (NBET), a Federal
AZURA EDO IPP
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DRAFT EIA REPORT