Search results for query: *

Compressor fan stops working while blower fan is consistently running. I need your knowledge and wisdom to resolve the issue. Appreciate! Heat pump is RHP13410A24J. Manual is following.https://www.hvac.com/media/manuals/installation/RHEEM13PJL.pdf Issue: when shorting Red wire and White wire...

All, There is a question regarding the location of line disconnect switch and line wave trap & tuner. As you may notice that wave trap and tuner is always installed at line side of line disconnect switch. The question I get is why not install the line disconnect switch at line side of the wave...

I am working on a 100 MW boiler proposal. In order to estimate annual coal cost, we need to know how long we will run the sootblowers. I have 52 sootblowers. Can I assume each sootblowers need 2 minutes to finish sootblowing, so total sootblowing time per shift would be about 100 minutes? I...

I am working on a PC boiler (100MW) unit and trying to calculate aux load at 30% MCR load. We have 2 PA fans, 2 FD fans, and 2 ID fan. 3 pulverizers. I knew that at 30% load, one pulverizer will be put into operation. At that time, the ID fans and FD fans will be up and running. However, I...

we are going to build a power plant in warm West Africa. I plan to eliminate the use of SCAH. Is it acceptable?

I am trying to specify the air heater type for an 830,000 lb/hr (378 metric tph) utility PC boiler. The fuel S content will be under 1% and I will set the flue gas exit temperature at air heater outlet to be 20-25F above acid dew point. For this size boiler, is tubular type air heater more...

When I use PTC 4 to calculate the boiler efficiency, I always perform a tested efficiency calculation and a corrected calculation and then compare the two efficiencies to make sure the difference is below 2% since we always pick a test fuel close to the design fuel. There is a different...

All, The following link contains a fault event graph. It shows that there was an event that ALL three phase currents were increasing for 4 ~ 5 cycles, however all three phase currents are in phase. During this event, C phase voltage is lower at 0.3 per unit. So, is it a single phase fault or...

138kV substation with 125 VDC battery A and battery B for protection A and B, trip coil 1 and trip coil 2, etc. The distance between two batteries is about 5 feet. I commented too close but have not find any reference to prove my feeling. Could you please help to enlighten me on this by...

Protection Guru, When checking 34.5kV feeder relay ground element settings for cable protection, is it necessary to consider protecting a cable from a feeder ground fault with all the ground fault current returned via the shield wire (1/3 netural)? Thank you, Best Regards, Bing

At transformer, there are tripping relays such as high winding temperature(49T), high oil temp (26Q), rapid pressure rise relay (63FP), main tank presure (63PR), Buchholtz realy (63Q) etc. What is the traditional way for those relays tripping? Shall those relays trip the lockout (86) directly...

Background: There are two 230kV stations within a same yard with a fence in between. Station 1 is a three 230kV breaker ring bus. Station 2 is a three winding transformer 230/115/34.5kV Yg/Yg/Delta with one 115kV line and one 34.5kV feeder. At delta tertiary, there is a grounding transformer to...

What is the purpose of a grounding transfomrer? My opinion is that For an ungrounded system, a grounding transformer is added to provide a grounding source in order to make a grounding overcurrent relay trips a ground fault at the system, so that cables and surge arrestors will not bear...

Question: Considering a 34.5kV feeder with dozens of WTGs (wind turbine generators), once the 34.5kV feeder breaker opens, will the WTGs be self-excited and continue energizing the islanded feeder? My opinion is that, since there will be a sudden active power changes, there will be a large...

Transformer: 230kV(Yg)-115kV(Yg)-34.5kV (Delta with a zig-zag grounding transformer). At 34.5kV side, there are two wind power generation feeders and a capacitor bank feeder. CT is 1200:5 C400. Available 3 phase fault is about 8kA and 1LG fault is about 5kA. Relay: SEL-387-5 Question: Is...

I have a transformer with the following data: 50MVA, 115kV-34.5kV-13.8KV, groundWYE/groundWYE/Delta Using Aspen software, I apply a single line to ground fault at 34.5kV side.(Note: there is no low side or other fault contributions). Zero sequence fault current at 34.5kV side is 5850Amp. Zero...