wcaseyharman
Electrical
We are in the process of having an EPC design a new solar plant for our company. The transformer is a 160MVA YDY 230kv/34.5 KV. Inverter isolation transformers are delta on the 34.5kV side. There are no appreciable LN loads.
One of the questions that has come up is the reactance of the neutral grounding reactor. I am trying to see what the pros and cons of increasing the NGR reactance from a typical 0.5 ohm to a 10 ohm to reduce the ground fault current to just above load current.
Theoretically this would reduce the stress on equipment due to ground faults and also reduce the step and touch potentials and improve safety. Some problems identified were issues with proper insulation coordination and surge arrestor selection.
Has anyone on this forum looked into this, and if so, what benefits and issues did you discover?
Thanks in advance!
One of the questions that has come up is the reactance of the neutral grounding reactor. I am trying to see what the pros and cons of increasing the NGR reactance from a typical 0.5 ohm to a 10 ohm to reduce the ground fault current to just above load current.
Theoretically this would reduce the stress on equipment due to ground faults and also reduce the step and touch potentials and improve safety. Some problems identified were issues with proper insulation coordination and surge arrestor selection.
Has anyone on this forum looked into this, and if so, what benefits and issues did you discover?
Thanks in advance!