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Hi, we have done straight through jont in a 33 kV UE 1c cable. After jointing, when we took the PI, PI is coming very high (more than 50 with 1 min & 10 min value as 5.98 and 342 M Ohm respectively). Can any one explain the phenomena pls?

Dear All, We are having a 16 MW 11 kV Generator. Recently thrust pad of machine got damaged. Mechanical team is fearing that it may be due to improper magnetic center of Generator. Please guide me on following: 1. If thrust pad can get damage due to improper magnetic center? 2. How to test that...

Hi, Kindly help me in getting / knowing the acceptable value of leakage current (fundamental as well as 3rd harmonic) for LA in 220 kV system? Regards,

I am having about 60 KM long 220 kV double circuit Transmission line, which passes through the forest and hilly area. During rainy season, heavy lightening takes place and causes the frequent tripping of line and on checking, we often find flash marks on the disc. Quite often, we found the flash...

Hi During routine inspection, we observed that counter reading of one of the 220 kV LA's has increased to 76 from 21 in one week time. I am arraning for checking the 3rd harmonic leakage current. Is there any specific reason for this sudden increase in counter reading can be ascertained and...

We have are supplying power to our Oxygen plant through 1.5 KM long cables. Cables are terminated to a 25 MVA Ynyn Transformer (33 kV / 6.6 kV) in open yard. LAs are provided just before the Transformers. Name plate details of LAs are: Metal Oxide, Rated voltage - 36 kV, Discharge current - 20...

We are having a large industrial load with about 500 MW internal generation. Our plant normally operates in parallel with Grid. In recent past, there had been severe frequency fluctuation in the Grid, which resulted into tripping of some of our internal Generators because of delayed islanding...

I want to know, where should we use high impedance differential protection and where low impedance should be used. What are the advantages & disadvantages of both schemes?

can any one provide me the data sheet showing parameters of different types of over head conductors (ACSR)?

Is there any symbol, which upon display can inform person regarding presence of Earth / ground mat in the substation?

We are carrying out DGA for about 300 Transformers on yearly basis. I am in search of a database management software to manage and interpret DGA and oil test data. Is there any readymade software available?

We are having about 5 KM long 132 kV, 4 nos Transmission lines protected with distance protection (PYTS relay, English Electric make). I want to replace the distance protection with Pilot wire protection using HORM 4 relay (Areva make). For this 5 C, 1.1 kV grade 2.5 mm2, armoured pilot wire...

Dear Friends, We are observing failure of 132 kV CTs. The frequency is about 1 no/ year but recently 2 CTs failed in span of 2 months. These CTs are about 10 - 12 years old and are of ABB make. I want to know: 1. Whats the failure rate of CTs in other location 2. Is there any test which can...

I am detecting electrical fault using a device working on accoustic principle. It gives dB measurement, based on which i can determine if particular installation is having some elctrical discharge or not. The problem is i do not know ho much db level could be allowed during electrical...

I want help from you people to understand the philosophy adopted to coordinate relay settings of Bus couplers. I am talking about a bus, which has 3 incomers, and each incomer is separeted by a Bus coupler. So there are 2 bus couplers and 3 incomers in a bus and normally bus couplers are...

As all of us know that there should not be a ring of megnetic material surrounding single core cable. My doubt is, if single core cable is passing through RCC roof, then it will be sourrounded by steel structure burried in cement and there maay be heating in steel structure due to eddy current...

Is there any thumb rule / standard, which tells about the ratio between total Oil quantity and Oil in Transformer conservator?

can some one tell me from where i can get bnchmark figures on auxiliary power consumption of thermal power plant, trnasmission , losses etc.

There is a small about 10 MW, 3000 RPM Generator coupled to a back pressure Turbine in our plant. One day, Excitation of the generator failed along with station DC power failure (supplied by 220 DC battery bank). Due to failure of DC power, no relay could the detect the loss of field / trip the...

friends, there r 2 big synchronopus motors of 16 MW and 12 MW in our plant which drives compressors. The Grid here is not very stable thats why frequency variation is from 48 Hz to 51.5 Hz.Due to high frequency, speed of motor increases which causes it to get overloaded. To reduce the loading...