remote synchronization

[odlanor]

In a system restoration after a black-start, it is necessary that the power plant will be connected to a system substation through a transmission line of 110km.
The synchronization equipment and synchronization circuit breaker are installed in the system bus running distant 110 km away from the generator bus incoming.
How to make an automatic synchronization knowing that the TPs are distant from governor/voltage regulator?

 

[davidbeach]

A perfect application for syncrophasors.

 

[odlanor]

-how to use syncrophasor to send signals to the voltage terminals of governor and voltage regulator?
-please suggest the necessary equipment.

 

[slavag]

Do you have some safety communication link between substations?

 

[odlanor]

David Beach
Attached is an example with GE synchronizer:
-bus running is at the substation system
-for simplicity, assume only GE4-T4 circuit. Bus incoming is at the power plant.
-GE synchronizer is installed at power plant.
- power plant is distant 110km from substation.

Slavag,
All communication link is by OPGW cables over 3 transmission lines.

How to connect:
- 25 at power plant to trip circuit breaker at substation?
- VT Busbars at substation with 25 at power plant?

 

[slavag]

option:
in the substation install local synchronizing panel with four push buttons (f+, f-, U+, U-), double voltmeter, double frequency meter, synchronoscope and push button for close command, of course any rotated switch local/remote or emergency operation and two pcs of binary to FO converters.
four signal (f+, f-, U+, U-) send to GE control panel via OPGW.

 

[86ed]

Odlanor,

Can you send a single diagram of your power plant? Typically BSDG sets are connected to a MV (4.16kV, 6.6kV, etc.) within your power plant. In my experience I have seen BSDGs synchornized accross the MV incoming breaker which is connected to the grid via a UAT-->GSU transformer--PTs were available on both side of the MV incoming breaker. I actually spoke with a SEL rep at a conference about a remote auto-synhchronization scheme using synchrophasors one time and he said it was possible. You may want to contact SEL.

 

[odlanor]

slavag,
good idea!

Could you explain better? : two pcs of binary to FO converters.

86ed,
what is BSDG?
where is remote synchronization in your example?

 

[davidbeach]

I've personally never done it, but SEL has papers on the process. A Phasor Vector Processor can do the math to produce your raise/lower pulses. You can have a virtual synch scope between any two point that can supply voltage phasers.

 

[odlanor]

slavag,

at local synchronization with the generator circuit breaker opened, the governor works with speed regulation. In this case, with the generator circuit breaker closed, the governor works with the power regulation.
Is this option a design practice remote synchronization?
Have you done this?

 

[rcw retired EE]

We have done it using RFL IMUX-2000 T1 Multiplexors with telemetry input cards for voltage and Model 6850 Remote Synch chassis at teh receiving end. The system transmitted the signals over fiber. Linear amplifiers at the power plant receiving equipment boosted the voltage signals to the 120V inputs to the turbine autosynchronizer. Local 25 synch check relays at the breaker location supervised closing.

 

[odlanor]

rcwlson,

Is closing command of circuit breaker originated from
automatic, remote,by autosynchronizer
or
manual,local, by substation operator?

 

[rcw retired EE]

Closing command was from auto-synchronizer that was adjusted for the signal transmission time delay. The system had dedicated fiber optic communications without multiplexors or switches so the signal transmission delay was almost negligible. The scheme also allowed manual closing from the power plant.

The line was a short 115 kV line (1.5 miles). There may be other issues to worry about on a longer higher voltage line.

 

[slavag]

I'm not done such system, but is not so important.
is not autosynchronization system, is manual control.
You will close breaker manually too.
Issue is sent 4 outputs via FO, 25 function is included in the local cubicle for safety issue.

4 outputs are like to any trip or block/enable commands (DTT, PUTT or POTT) .

Again, it's same as manual control from control room, only instead wiring, fiber optic.

 

[odlanor]

I guess slavag solution is more efficient. Teleprotection equipment permits 4 or 8 independent commands. We can use 4 command to DTT, PUTT or POTT and 4 commands to U+-,V+-.
Thank you guys!

 

[breadboard]

This might be a dumb question but can't the far end of the 110km line synch with the system first then the local end after that?

 

[odlanor]

Yes. Living bus incoming-dead bus running is a mode of synchronization we hope be the mode adopted.