Substation Metering
Substation Metering
(OP)
For efficient three phase metering in a substation,what is the minimum number of ct and pt required.
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RE: Substation Metering
What quantities are you trying to meter?
Are there any single phase loads?
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If we learn from our mistakes I'm getting a great education!
RE: Substation Metering
RE: Substation Metering
Alan
RE: Substation Metering
Blondel's theorem states that "If energy is supplied to any system of conductors through N wires, the total power in the system is given by the algebraic sum of the readings of N wattmeters, so arranged that each of the N wires contains one current coil (transformer), the corresponding voltage coil being connected between that wire and some common point. If this common point is on one of the N wires, the maeasurement may be made by the use of N-1 wattmeters."
So if you research, you will find 2-element, 2-1/2 element, & 3 element meters. The element is the number of PTs & CTs where for example, a 2-1/2 element is 2 voltages & 3 currents.
The 2-element & 2-1/2 element will introduce errors if the system is not symmetrical/balanced but it depends on your reason for metering & if you can live with these errors.
There are numerous manaufacturers of industrial grade meters. I personally like the SEL-734 for the cost & features.