Thank you folks.
I have been doing lighting studies for a long time and I am of the opinion that a study should always be done for a large project interior (data center, air traffic control room, clean room, etc) and exterior project (parking lots, wall washing, etc).
As expressed by some of...
Some technical folks where I work say that a lighting study is not necessary for new lighting system installations because human perception is subjective. Other say that the study gives you basic information about the lighting levels.
I personally use AGI32 for every lighting study I do. It...
Hello:
We are in the process of upgrading our relaying system at our main substation. We are replacing all of our Westinghouse/ABB electromechanical relays with SEL relays + a SCADA system.
One modification that has caused concern is the replacement of the individual 15kV air circuit breaker...
Hello:
Short of doing an EMTP study is there any approximate method of determining the placement of surge arresters along a medium voltage aerial feeder?
rbulsara:
Initially, the 3000AF had a 1200AT plug to comply with NEC and protect the 1200A Al Feeder. This feeder services a dedicated load of HVAC equipment (smoke mode control exhaust fans, elevators, central station lighting).
A 3000A busduct was installed and will feed a separate dedicate...
Please consider the following:
1. Existing E/G system is a random access, parallel, three E/G switchgear.
2. A 3000AF drawout power breaker on E/G switchgear is presently serving a 480Vac, 1200A load using 4/phase 600MCM Al conductors. The linear distance is approx. 1000ft.
3. A new 3000A, 3...
Last year (May, 07) I brought to the attention of this fine forum the fact that I was the only electrical PE in the federal agency branch where I work. The situation is still the same. I asked our legal department about the ethical issues involved and I am still waiting for an answer. I did get...
Hello:
Can VFDs work with regular motors? What parameters should we observe?
At my agency opinions are divided on this issue: VFD rated versus non-VFD rated motors.
Thanks,
Jimmy Junior
Recently our engineering group purchased and started installling 4 firepump assemblies in our utilities plant. Each of these assemblies consists of a firepump controller, a pump and a 250HP motor. The decision to replace the older firepumps was made because the older pumps were installed in...
Hi:
I have a question about application engineering in the context of interior double-ended substations. To wit,
is it warranted to install TVSS protection on the secondary sides of double-ended substations between the transformer secondaries and the main secondary breakers (480Y V or 208Y...
Our principal administrative building is a 4 story office building served by six substations. These consist of 28 year old Westinghouse 12.47kV/480Y/120V and 12.47kV/208Y/120V double-ended substations. All of the transformers except for 3 are Westinghouse originals. All of the substations are...
At our federal agency we have at our Main Substation two 69/12.470kV, 15/20MVA, transformers feeding two walkin breaker lineups. Each lineup is fed from one transformer and the two lineups are connected by a NO tie ACB. Presently the transformers are protected by S&C Fuses. Soon S&C...
Hello:
I have been involved with Power System Analysis since 1976, before the advent of the PC. Back then we used main frames to perform short circuit calculations.
Where I work I am the only electrical engineer (and only EE with a PE) that has this kind of expertise and experience.
My...
Hello:
I am an electrical engineer trying to convince the folks in my group that when replacing a 1940s vintage 50hp pump motor with a modern energy efficient replacement, a lot more has to be done than just supplying the nameplate data. I think that proper engineering practice would dictate...
Hello:
I work for a Federal Agency as a Senior Electrical Engineer and have been a PE for 27 years. Our engineering department is multi-disciplined. All of our Branch Managers are PEs also. There are presently several electrical engineers working here, but I am the only PE. Our Agency does...
