The maximum load in kVA the transformers can supply (combined) without overloading any one , is determined by the transformers impedance. They load up inversely proportional to their impedance.
Determine How To Load Two Paralleled Transformers Read More »
POTT scheme works using the following logic:
Fault in Zone 2 AND permission-to-trip signal from remote end relay.
Permissive Overreaching Transfer Trip Scheme (POTT) Read More »
Pole mounted transformers for station service in substations or to feed residential or commercial buildings are fitted with mounting lugs that are sized per the IEEE standard C57.12.20. The transformers covered by this standard are 500KVA and smaller; High voltage, 34,500V and below; Low voltage, 7970/13,800Y V and below.
Mounting Provisions for Pole Mounted Transformers Read More »
In the realm of protective relaying, overcurrent protection is the simplest and an essential scheme. Phase and residual protection are quite common in the industry. Phase elements should be set carefully so as to afford protection for equipment downstream of it while not limit the load current in anyway. Residual currents can be set more sensitive than phase relays since they do not limit the load current. Between these two, it is easy to forget the negative sequence protection.
Enhance Your Power System Protection With Negative Sequence Relaying Read More »
Any relay that receives CT input, be it from the breaker bushing, transformer bushing, or a stand-alone CT bushing – needs to have its neutral circuit grounded. Grounding shall be done at only one location along the entire length of the circuit.
Grounding And Shielding Cables – Best Practices In Wiring Equipment In A Substation Read More »
