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Hi, this is the reply from the supplier:- translated from Chinese (Mandarin ) to English. The terms not very correct I guess since I cant read Chinese Mandrarin. "The CT connection shows on the pictures is not for neutral point connection or for CT coil grounding . It is for equal potential...

Hello, We have current transformer at neutral point of the generator. Strangely there is a metal braid connection from the body (cast resin) to neutral point phase conductor of the generator. (I assume its for the CT iron core) We have this metal braid from all CTs to its respective phase...

Hello, In our Micom P633 transformer relay, we could not get the "Idiff" and "Irestain". The rest of the measurements are ok. I could be looking as the wrong group as it is on 'FT_DA' (which is fault recorder). If I extract setting in the setting file than I could see the actual reading of...

Hi ZabSib, Sorry for very late reply. Yes, it is as what you said. Modification on PSL has solved the problem. Further mode we have also Lorck Our Relay. We also make use of this contact as an Input to give have the trip active. Thanks for the feedback.

Hello Guys, Now the client have new request about the tripping sent via fibre optic. They wanted the trip to be latched. From ourside we made the trip send to be latched (intertrip CH 1) is active until we reset at ourside. I am trying to figure it out how to make the trip via Fibre Optic...

Hi DiscoP, Thanks for the feedback. The relay address were wrong. We established connection and we did as well send trip to the remote relay. Thanks for the tips.

Hi DiscoP, Thanks for the clarification. The transformer rated current current is 794 Amp. CT ratio is: 1200/1 Amp CT secondary rated current 794/1200= 0.66 pu Is1 setting is 0.3xIrated = 0.3x0.66= 0.198 pu I was mixed up. 0.66 amp is the transformer secondary rated current. In the test...

Hi DiscoP, Thanks for the feedback. Yes. You are correct the DDB was wrong. I was looking at the manual for Micom P543. After assign the correct DDB the relay tripped for Diff B,C and later A as expected. The thing I tried to understand is when I inject in Phase A, the relay tripped (Idiff A)...

Hi All, I have been trying to inject current for Micom P542 and the setting of the relay is: Is1= 0.2 pu Ki= 30% Is2= 2.0 pu I was checking the low set of the cable differential protection function. I did exactly the same like in the manual and the monitoring Bit in the Commissioning Test...

Hi rasevskii, Thanks for the reply. It is a Dny11. We are testing the protection relay and all the secondary injection done from relay terminal at relay cubicle. Soon maybe I will try to inject it with 3 phase current supply and have monitor the differential. But I do not know if it might...

Hi all, Once again I need a advice from gurus here. we need to prove the transformer differential setting to our client. Relay used to protect 2 winding trafo. Diff trip works fine when we inject only at HV winding (winding a)relay CT terminals (single pahse injection and 3 pahse injection)...

Thanks for the feedback guys, Looks like voltage divider and length of the insulator definitely can be related to that scenario.

Hello Guys, On our site 400KV trafo bushing and insulator was cleaned with Online Wet washing last week. The supplier for the washing system was onsite for cleaning. Only for the first time. We had a good water resistivity 5 micro siemens/cm. And at 25bar from the pump cleaning was done with...

hi elecpl123, I have attached a file of the GCB close open operation. For this GCB the manufacture take the time between when the NO contact close and opening of the main contact as OPEN CLOSE time. Which is a bit lesser than normal CLOSE OPEN time. maybe somebody can help. Thanks...

Hi warros, I measured the current and I am scared. Neutral point of the Step up has a surge arrester rated for 132kv connected in parellel. No current via the surge arrester grounding when I measure. If I measure at the grounding of the Neutral point I have about 4 Amps (50Hz). Transformer...

hi palakjignesh, normally there will be plunger (usually protected by protective cap. near the Buchholz relay and you can see the movement of the mechanism from the sight glass. If u have two stage of tripping then you have to press the plunger slowly down for stage 1 trip and further down for...

Hi warros, I totaly agree with you. The workmanship here is quite poor. I am aware of danger working on GSUT when it is loading. I have to be carefull. Thanks for your advise. Thanks alot guys.

SOrry for the late reply, Hi protection engineer, I have attached the print screen of the Micom P633 in my fist post. Luckly we have solved the problem since the CT connection was wrong at the gen. step up trafo. For the plant tripping on sudden deloading we have found the cause( hope)...

the unbalance current still there even at 30%(50MW)load. we checked the tap changer and seems fine(only visual inspection). You guys have any idea about the sudden load decrease from 50MW till the generator trip on reverse power (low set)? We experienced this today. We had few times the same...

hi warros, we have solved the diff prot. trip. (the CT polarity was GSUT, now is ok) Our GSU Trafo is delta (14.5kv) on generator side and Star on grid side(225kv). Please explain me what is hanging tap. Thanks