DC earth fault relay is commonly used to detect earth fault in DC systems. An ungrounded DC system is used to control the supply of protection systems, control panels, communication, and other networking devices. When one terminal of the DC system is grounded, it is not creating any problem. However, when both the DC terminal … Read more
Anti pumping relay is used in the circuit breakers to prevent unwanted closing of the breaker after immediate tripping. Due to failure of the TNC switch (Trip normal close) or any other discrepancy in the CB closing circuit, continuous CB close command can be extended to the closing coil. In that condition, after tripping the … Read more
The trip circuit supervision relay always monitors the healthiness of the trip circuit including a connected trip coil of the CB. Tripping or isolation of CB is the most important part of power system protection. Always 02 nos. trip circuits are used in the CB for system redundancy. Due to the failure of the trip … Read more
Grading capacitor is commonly used in High Voltage Circuit Breaker for uniform voltage distribution across the Breaker contacts at CB open position. In a multi-break Circuit Breaker, Grading capacitors are connected in parallel with every break of the CB. Reasons for using Grading Capacitors in Circuit Breakers. When the capacitors are connected across the breaks … Read more
DGA (Dissolved Gas Analysis) is an important tool for checking the healthiness of oil-filled power transformers. Power Transformer is important and expensive equipment in Power Transmission and Distribution systems. Periodic checking or testing of the transformer is done to maintain the healthiness of the transformer. Transformer oil is used for insulation and cooling of the … Read more
When the voltage goes higher than the rated voltage is called Over Voltage. It is a very common issue in Power systems. System voltage is to be maintained as per the designed voltage for the stability of the power system. All the equipment and insulators used in substations and transmission lines are designed for a … Read more
After opening the Circuit Breaker under load or fault condition, a transit voltage appears across the breaker contacts which is called Restriking Voltage. Frequency of Restriking voltage goes in kH. During arcing period, transient voltage appears across the contacts at or near current zero. If dielectric medium between the CB contacts is greater than the … Read more
The Corona Effect is the phenomenon of electric discharge in high voltage transmission lines and substations. Hissing noise and violet glow were observed under the corona effect. Power loss, damage to high voltage electrical components, and noise are observed due to corona discharge in the Transmission line. Why does corona effect in transmission line? Due … Read more
Cable lugs are used for termination or connection of cables to the Terminal Box (TB). There are so many types of cable lugs are available based on the cable size. They are mainly copper and aluminum type. Based on the application of the cables, following types of cable lugs are used for cable termination /connection … Read more
REF relay stands for Restricted Earth Fault Protection. It is an earth fault protection, and it will cover the protection for a particular area or zone. Generally, it is used to detect internal earth fault of a Power Transformer or Reactor. As the earth fault protection is cover for a particular area. It is called … Read more
