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 »
Let’s understand the concept of per unit system by solving an example. In the one-line diagram below, the impedance of various components in a power system, typically derived from their nameplates, are presented. The task now is to normalize these values using a common base.
Per Unit System – Practice Problem Solved For Easy Understanding Read More »
These terms were coined over a time period to identify the appropriate short circuit current magnitude that engineers could use to size the switchgears, switchboards, panelboards, and the circuit breakers.
What Do Symmetrical, Asymmetrical, Momentary, Interrupting, Close & Latch Ratings Mean? Read More »
