PASCOR offers surgesuppression resistors for applications on 138kV, 230kV, 345kV and 500kV vertical break disconnect switches with one, two, three, or four modules respectively.
Resistors are static, oil-less and maintenance free. They can be adapted to any manufacturer’s vertical break disconnect switch. Modules are pressurized at the factory with dry nitrogen, no field filling is required. Resistor assembly is easy to install.
In the closing process, the current inrush is reduced dramatically. In the opening process, there can be high over voltage when the deenergization takes place, and with resistors this can be dampened dramatically. The opening and closing processes are dampened which prolongs transformer life. An important application is for switching platform charging current in 500kV series capacitor banks.
PASCOR’s modular resistor primary objective is to limit surge currents and transient voltage when switching transformers.
As an economy measure, even rather large unloaded power transformers are frequently switched by disconnect switches. Transient overvoltages, particularly at 345kV and above, can be sever. The magnitude depends on the inductance (L) and the capacitance (C) of the system.
There are three rather distinct advantages to having the resistors when switching with a disconnect switch. That is:
There is reason to believe the dampening processes described above will extend the life of the transformer.