Synchrocheck relay protection 1

[MartinBEng]

I am using a Crompton Synchrocheck relay 244-14hg to synchronise 2-3 generators in my factory. The relay blew some time ago and was replaced, it has blown again. I believe transients may be causing the relay to be damaged. Does anybody know of suitable voltage suppression units or any other ideas for additional protection?

 

[busbar]

Given grounded-secondary PTs, if the generators are of any significant value, it may be funds well spent investing in a simpler, more rugged induction-disc relay, like an IJS-type device.

Aftermarket transient protection for somewhat essential supervisory devices seems to have a very limited success record; id est, why has that not been built into the device at the design stage?

 

[peterb]

I'm not familiar with the particular device, but I am aware that Crompton has a line of DIN rail-mounted protective devices that are what is referred to as "industrial grade", as oppsed to "utility grade".
The main question here may be whether or not the device is qualified for use in substation environments (to ANSI C37.90). If not, then I suggest checking with Basler, Beckwith, ABB for appropriate synchrocheck relays.

 

[jklf12]

The following relays can be incorporated which can suppress the harmonics or transients

1) SCM21 of Micro Italia
2) MAVS 01,02,03 Alstom Make
3) 7VK512 Siemens Make

Try you will find better solutions.

 

[jbartos]

Suggestion: It may pay off to troubleshoot the existing relay wiring, connections, add TVSS, etc. A little analysis of the relay incorporation may be found useful for other types of relays since the basic synchronism-check relay (25) principles and functions will stay.

 

[ScottyUK]

Have numerous MVAS relays as made by GEC prior to being absorbed into Alstom on site, and have never known one fail to date. I would therefore recommend them as a satisfied user.

Relays are on our internal 11kV and 3.3kV networks fed from our own output and NGC transmission system. VT's have normal grounding arrangement.

As you running up to three generators on site, how stable is your site voltage? Could it be that the relays are gently cooking themselves over a period of time?

 

[sandipsvaid]

is there any control scheme such that synchro-check relay gets disconnected when it's operation is over .

either relay may remaining in serivce continously that may leading to damage to the relay.

kindly confirm

 

[busbar]

sivaramen, as to the differences between utility and industrial grade, an example of a utility-grade device 25 would Basler BE1-25

http://www.basler.com/downloads/ubp5bull.pdf

where “industrial” would be BE3-25

http://www.basler.com/downloads/ula1bull.pdf

There are major differences between the two for support documentation, reliability, stability and serviceability. The “industrial-grade” assembly is typically discarded if problems develop. In most cases, US electric utilities will not permit use of non-utility {industrial} grade components in interconnection gear.

 

[ohhn]

I've never had a syncrocheck relay blown in any installation I've commissioned, with the exception of one that we burned in a new installation because it was wrongly wired.
Please check the wiring and/or if this equipment utility graded as was recommended.
Please advice when you find the problem since I may find it in the future.
I ask for the advice since I hadn't come to this forum lately due to lack of response from the people who ask originally, even when asked.

 

[jbartos]

Suggestion: Visit

http://www.platts.com/engineering/issues/Power/0107/0107pwr_srhydro.shtml

for a distinction between industrial grade and utility grade. The former tends to be less reliable and often breaks.

 

[jbartos]

Small encore: Visit

http://www.pge.com/002_biz_svc/gen/pdf/wi_handbook/g2.pdf

for G2.3 Relay Grades