Black Start Generators Wiring Diagram/s 7

[Crie]

I am doing a small diesel power plant with 1.25MVA capacity. It is stated in the specifications to provide black start generator. Do anyone here advice me on how to size the black start generator and provide reference on how it will be installed? Is it really important to the system? I'm not really familiar with this type of generator.

 

[mgtrp]

A black start generator for a 1.25 MVA diesel generator? Your diesel generator almost could be a black start generator for a larger power station! We typically use either compressed air or batteries to start the generator, not a black start generator.

 

[burnt2x]

Example: One of our remote diesel power plant is composed of 4 X 11.25 MW units. The blackstart generator is a 400 kW Detroit 480V generator. The blackstart generator loads are mostly air compressors, lube oil pumps, cooling water pumps, air cooler fans, main fuel pump and an electric fuel oil heater! You can include the lighting fixtures of the power house as loads as well.

 

[rcw retired EE]

A 1250 kVA unit should be able to blackstart it self off batteries.

 

[DTR2011]

You need to verify the settings on the sync check relay to allow closing the breaker on a dead bus.

 

[gvasiliou]

Black Start Generators (BSG) are used in power plants to provide the "first" source for the auxiliaries subsystems of bigger engines/turbines to work.

For sizing
You need to know from customer what is the load/s that Generator is going to get, in how many steps. Also is good to know if the loads have some particular "limits" on Voltage/Frequency. This data will affect the BS generator selection.
For example assume that the plant has completely stopped - black out.The first source will be the black start generator of 1,25 MVA, providing electricity to a part of the power plant.
Assume that the first turbine oil pump will be coupled to the BSG. If this oil pump is rated at 600kW and starting method is DOL then for sure you will not be able to start the pump with 1MW BSG. The reason is that the impact of the 600kW motor to your BSG will be that much that will cause voltage and frequency to drop too much, that most probably will exceed the motor under frequency/under voltage limits.
PS : In some very bad cases , the BSG may be shutdown at once...

On the other hand if you plan to couple smaller loads in a lot of steps , 1MW is fine. It is all related to the load/s you plan to couple.

For automation , is just like the smallgreek said.
You just need to allow closure of BSG breaker bypassing the synchronizer circuit. You have to be careful on this to ensure that you will not close the BSG breaker on a live bus without synchronizing. Usually we allow "bypass" of Synchronizer and we force BSG breaker closure ONLY when the bus behind is dead (black). You need first to check if the bus is dead , and then to allow closure of circuit breaker without synchro check.

 

[FreddyNurk]

Are you sure the specification doesn't say that the 1.25MW station is capable of black starting?

What is the station itself for? Peaking? Supply to a remote community? This may help indicate what is meant in the specification.

All of our (remote, isolated network) stations have the capability to bring the station up from a black start, a few of them have installed capacity of 1.25MW.

 

[waross]

The black start capability of our old pland 3 x 350 KW and 2 X 600 KW was a small diesel engine driving an air compressor. Normally an electric pump maintained the air reservoir but if for some reason we lost our starting air we could rebuild starting air pressure with the diesel engine driven compressor. Those sets have since been replaced with 1.2 MW battery start units.
Who makes you diesel engines?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[abo2eyes]

what about the manufacturer of your generator recommendation it is not standard it differs from one type to another so u specified your load with 1.25MVA select your manufacturer and see the recommendation

if u are making a new design of diesel generator u have to calculate your emergency loads

 

[abo2eyes]

what about the manufacturer of your generator recommendation it is not standard it differs from one type to another so u specified your load with 1.25MVA select your manufacturer and see the recommendation

if u are making a new design of diesel generator u have to calculate your emergency loads



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