HV Switchboards Flashcards
Name 5 reasons for IEP
- Economical
- Flexible
- Load diversity
- Ease of control
- Low noise & vibration
The switching of IGBT causes harmonic current which causes what?
- Voltage distortion
- Zero crossing noise
- Unbalanced line currents
- Overheating
Neutral earthing resistors
What does NER do?
Limit earth fault current to 10Amps
Where is the NER connected to?
Star point
On a T45 what 5 items are within in the HV swbd room?
- 7 HV VCB’s
- DG AVR
- GTA AVR
4.Prop converters
5.HV Harmonic
WHat do HV harmonics filters do?
reduce the heating effect caused by harmonics & corrects the power factor
What is steady state voltage?
Where V & I aren’t changing
Active
Where does LV harmonic distortion come from?
- Prop converters
- non linear consumers
What 3 modes can the Emgen run in?
- Auto
- manual
- Test
T23
What do the Air breakers & all other breakers on the swbd do?
- Over I protection
- Under V protection
- Reverse I protection
- Fault discrimination
- Open & close safely
Name the 5 main breakers/switchgear on t23 LV swbd
- Supply (Gen to swbd)
- Feeder (Power to EDC’s)
- Interconnecting (Fwd & aft swbd)
- Linking (Links swbd section)
- SS/Ship alongside
On a t23 what does the emergency swbd supply?
- 5 HPSW pps
- 5 Smoke clearance fans
- Portable damage control sockets
- Sick bay
- Emergency lighting
- Steering gear
What is a converted supply?
Any supply derived from 450v,60hz ,3 phase that has changed it’s Hz or V
What equip is on T45 IEP?
- 2 WR21 GT 21.8MW
- 2 diesel engines 4160V/2MW
- 2 x 2MW tx
- 2 HV harm fil
- 2 LV harm fil
- 2 Hv swbd
- 2 LV swbd
- 4 NERS
- 6 DBR,s
What is a converted supply?
Any supply derived from 450v,60Hz,3 Ph & had Hz or V changed
(except 115 v, 60Hz,1 ph lighting)
