Diesel generator station (EDGS) is an emergency source which provides emergency supply of NPP appliances in case of electric power loss. EDGS is adjusted to take-over the load and to perform its function anytime except the repair time. From this reason it is permanently in “hot standby“ mode.

EDGS is preferably designated for automatic start when emergency signal from superordinate safety system is actuated and for consequent electric power supply. It is set to remote control from the Main Control Room, of course it is possible to control the diesel generator from its position.

Diesel generator station consists of diesel engine, generator and support systems for its operation (diesel economy, oil economy, cooling system, air-conditioning, fire system etc.), where our team worked (more than 120 people) and in common we completed this project by putting into operation finished by functional tests and permanent 72 hours operation.

The project of designing and manufacturing of 2 sets of mobile diesel generator (mDG) JULLY 800 was implemented by own research-development, manufacturing and implementation capacities with an aim to assure electric power in case of “station black out“ (SBO), mainly for charging of accumulator sources and to assure power supply at classified appliances during the SBO, including boron water feed pumps – to enable their operation during SBO. The concept of MDG is designed in units, it means one independent MDG for each unit of MO34 power plant.

The main part of mDG in the container design is the engine and generator. Furthermore the mDG contains control switchboard, power switchboard with 3 pole circuit breaker of the generator. The engine with the generator is positioned on the common welded steel frame, secured by flexible elements. Flexible positioning is to restrict spreading of vibrations and shaking from the floor of the mobile diesel generator room. Because of flexible positioning of the apparatus all the junctions to spare source are secured by flexible connections. Except of own springing of the engine with generator also the mDG frame is positioned flexibly on the mobile chassis structure. The chassis frame is designed based on actuating frequency, total weight and position of the mDG centre of gravity.

Start-up standby power (NZZ) is by its design and power output designed to meet required parameters for “external steam“ which is necessary to start up one of any boilers of Units no. 1 and 2 of ENO B and fluid boiler FK1 of ENO A. During the start to, the mentioned big sources can be in any stage of cooling, in hot condition but also in cold condition.

NZZ from its starting up point of view an autonomous, capable to start-up without any need of external medium (except operational media) to its operational parameters and consequently it is capable of automatic operation. Steam power output from NZZ is into existing steam interconnection of ENO A with ENO B.

NZZ consists of following basic technological parts:

• Steam boiler with accessories,
• Fuel economy of engine diesel,
• Combustion products removal, stack,
• Thermal treatment of feed water, including chemical after-treatment,
• Connecting pipeline of own NZZ as well as connection of operational media in ENO A,
• System of electric power supply,
• System of inspection and control.

General characteristics:

Output medium:

superheated steam

Nominal steam output

21,20 t / h

Maximal permanent steam output:

21,20 t / h (when keeping the steam temperature of 270°C)

Minimal steam output:

5,00 t / h

Nominal pressure of superheated steam:

0,7 MPa (g)

Superheated steam temperature:

270  °C

Feed water temperature:

105  °C

Nominal heat output of boiler:

15,24  MW – at 25°C

Nominal heat input of boiler:

16,94 MW (for engine oil) – at 25°C

Combustion product temperature behind the boiler:

262 °C

Boiler efficiency at reference fuel (NM) and ambient temperature 25°C and at:

• Nominal steam power output

89,3 %

• Maximal permanent steam output

88,8 %

• Minimal output

91,3 %

Type of combustion process:

pressurized

Boiler control capability:

25 to 100 % of nominal output

Main fuel (reference fuel):

Engine diesel (summer, interim, winter)

Alternative fuel:

Natural gas

Fuel for burner ignition:

bottled gas