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I am working on a relay panel project. Customer asking for install relay alarm cutoff and relay trip cutoff switches. Used Flexitest FT-1 before. But here are the customer requirements: It is requrested to two control switches in each relay panel. 1. Relay Alarm Cutoff: Disable any local relay...

Currenly reviewing an event for a small Microgrid system. Need some insight on the following scenario: 1. When the system became islanded, the diesel was started to provide aux power to start other engines. 2. Lead engineer #1 was started. (5MVA) 3. Then #2 and #3 were started to take loads...

mcgyvr; It has screw connector. So what should be used? Thanks

Hi, here is a question I need help. A 3/C #14 AWG Rockbestos cable for a Astrodyne power supply (30W, 120VAC input) has been routed. Then it was found out that power supply can only terminate #18 AWG cable. Can some kind of adapter be used? I have no such experience before. Please advise. Thanks

Hi, I am looking for a Aux PT to step down voltage from 208V to 120V due to the unavailability of 208V model of the ABB 60Q relays. The current available PT signal is from Y-Y PT which is only in 208V L-L. Any suggestions are appreciated.

Hi; What is the impact of 2-winding transformer Buried Delta Winding to the system response? Does it have to be modeled for Load Flow, Short Circuit or Motor Starting studies? Thanks

We have 6.9KV system powered by Emergency Generator with high resistance grounded. It is a requirement that the system will stay in operation for first ground fault, considering its emergency functions. The questions are, under the condition: 1. Will the 8KV cable be specified with 173%...

Our foreign client has a question on momentary loss of MCC control power. They want to know the US practice of countermeasure against instantaneous power loss for MCC. MCC uses step-down power from main power for control power. Contactor will open in instantaneous power failure condition on...

IEEE 484 requires less than 2% hydrogen accumulation, while NRC RG 1.128 goes further by requiring 1% for any new plant projects.

I understand hydrogen is generated during battery charge mode and the generation will stop after switching off the charging current. My question is if the ventilation fans can be turned off at this moment? You may say hydrogen gas is still trapped in the plates and inside the cell and may come...

Hello. I have a question on selection of voltage level for a group of motors. What is the maximum allowed HP ratings for 480V? In other words, when a motor have a larger size than that, it has to be rated at the next higher voltage level. I was told 200HP might be the number. But I could not...

I am currently working on a 5kV distribution system which consists of 6 miles of 5kV transmission lines. The load is about 200Amps. Can somebody help by telling how many poles and any other equipment I need? Or a rough number of cost per miles would be greatly helpful. Appreicate any input.

I am currently working on a 800KV HVDC transmission line project. We have a couple of converter stations at the sending end (about 10km apart between each other). All the lines for them will eventually stay nearby to be built in the channel. I'd like to know whether there are any standard...

I am currently looking for a mini wind power generator, which should be at the level of 10W or less. This will be used as power source for railway control signal at a freight train. The client does not like the idea of installing a battery. So I am wondering that anybody can tell me where to...

Our project has GE's UR series T60 transformer protective relay. The percentage differential function has dual slope adjustability, with Break point 1 as the turning point. The selection for this point requires it to be below a current that could cause CT saturation due to DC component. The...

I am looking for information on the power transformer on-site testing requirement. Is there any requirement from IEC standard? Any input is appreciated.

Since matching transformer is connected as star-star and the ratio is 1:1, I don't see its necessity in the circuit.

For protective relaying circuit such as transformer differential protection, there are two sets of bushing CT used, on the HV side and LV side. The question is where should the CT be grounded? At the transformer side which is in the transformer control panel or the relay side which could be 200...

Kantor - Thanks. Yes. We do have an automatic synchronising system and an AVR. Our starting system is a GE MArk VI speedtronic system. The GT system is GE 9FA Machine.

For Combustion Turbine Generator like GE's machine, we use static start system to start the machine. There is something which I am not sure here. First the machine is running like a Variable Frequency Drive, powered by the static start system. Then the machine is driven by the Turbine, as a...