Main Generator Excitation And Regulation(MB)

Question 1

What’s the purpose of Main generator excitation?

Answer 1

•To supply DC power to the Main generator rotor, to generate a magnetic field.

Question 2

What’s the purpose of main generator regulation?

Answer 2

•To monitor main generator output voltage and current and controls the DC excitation current to the rotor.

Question 3

How is excitation provided during generator start up?

Answer 3

•By non-class 480 MCC.

Question 4

Uses DC current to excite rotor field windings

Answer 4

•Excitation

Question 5

List major equipment in the Ex2100e Excitation system

Answer 5

•Power potential transformers
•Power conversion room
•Ex2100e control system
•Mark Vle balance of Plant control system
•Support Equip.
-HVAC
-Fire protection

Question 6

Describe the purpose of the Power potential XFMR
(MBN-X01A,B,C)

Answer 6

•To step-down the 24kv from main generator to the 1050v so it can be used by the Ex2100e excitation system.

Question 7

What are the two methods of regulator control(MB) to the operator in the Control room?

Answer 7

•Automatic AC regulation
-Generator output voltage is sensed and the regulatory automatically controls the DC field current to the main Generator.

•Manual DC regulation
-Operator manual sets a specific DC field voltage.

Question 8

What kind of rectifiers are used in the Ex2100e?

Answer 8

•Power bridge rectifier’s are used to rectify AC to DC

•Each power bridge rectifier has 6 silicone controlled rectifiers to rectify 3phase ac into dc

•3 are in service, 1 is in standby
•Each one can be isolated

Question 9

Describe cooling fans for Excitation

Answer 9

•Each cabinet in the power room has two fans above them.
•The 4 rectifiers, AC input, DC output, and excitation control cabinets.
•They run in a lead-lag design so if one fails the other fan kicks on

Question 10

Describe the power source for the cooling fans in the ‘power room’

Answer 10

•Two 480v LC are supplied to the fans through a distributor panel.
•They have an ABT(Automatic bus transfer) if power from one supply is lost.
•If both power is lost then the standby rectifier kicks on.

Question 11

Describe the purpose of the Power Conversion Room(PCR)

Answer 11

•The PCR houses the equip. for the Main generator excitation and regulation system

Question 12

What sub rooms consist of the Power Conversion Room?

Answer 12

•Control room
•Power room
•Air Conditioning room

Question 13

Describe the VESDA fire detection system

Answer 13

•Alerts control room of fire on board six and plant fire protection system in the SSR room

Question 14

Describe the STAT-X fire system

Answer 14

•It’s a fire suppression system
•Electronically actuated by a local hand switch
•does NOT automatically activate
•Once the agent is activated, the ACU lose power which will lead to the exciter shutting down

Question 15

What temperature does the ACU’s keep the PCR and with how many units running?

Answer 15

•They keep the room between 75-85degrees FAHRENHEIT
•Normally with only 1 running

Question 16

What temp do the heaters keep the PCR room above in winter?

Answer 16

•They keep it above 55degrees FAHRENHEIT