Directional Static Overcurrent Relay: For obvious reasons of obtaining selectivity overcurrent relays are made directional. Directional static overcurrent relay senses direction of power flow by means of phase angle between V and I. When the phase angle between V and I exceeds certain predetermined value, the directional relay operates with a condition that the current […]
Directional Static Overcurrent Relay Read More »
What is Summation Transformer? Summation devices are employed to compare the relaying quantities derived from the currents in the three phases of the primary circuit. The effectiveness of the comparison of the derived relaying quantities may be considered in terms of the effective ratio of the primary currents under comparison, such as at the two
What is Summation Transformer? Read More »
Difference between Static Relays and Electromagnetic Relays: The conventional electromagnetic relays are robust and quite reliable, but are required to operate under different forces under fault conditions. This leads to delicate setting small contact gaps, special bearing systems, special clutch assemblies and several measuring problems. These require instrument transformers (CTs and PTs) with high burden
Difference between Static Relays and Electromagnetic Relays Read More »
Powder Coating Process: Powder coating process is one of the most durable finishes that can be applied to industrial manufactured products, and offers excellent corrosion protection and is very safe. Purpose of Power Coating Process: The basic purpose is to carry out pre-treatment before powder coating process. Normally 7-10 tanks are used for hot process
Powder Coating Process – Problems and Parameters Read More »
Zero Sequence Current Relay: This type of zero sequence current relay is similar to that of negative phase sequence relay as discussed in article Induction Type Negative Phase Sequence Relay. The relay is made to respond to the flow of zero sequence currents also by providing another winding on the central limb of the upper
Zero Sequence Current Relay Read More »
Induction Type Negative Phase Sequence Relay: This type of induction type negative phase sequence relay has similar construction as that of an induction type overcurrent relay. The difference lies only in the primary winding provided on the central limb of the upper electromagnet which is provided with a central tap resulting into three terminals 1,
Induction Type Negative Phase Sequence Relay Read More »
Negative Phase Sequence Relay: A negative phase sequence relay (or phase unbalance) is essentially provided for the protection of generators and motors against unbalanced loading that may arise due to phase-to-phase faults. Essentially such a relay has a filter circuit which is responsive only to the negative sequence components. Since small magnitude overcurrent can cause
Negative Phase Sequence Relay Read More »
Voltage Balance Differential Relay: In this voltage balance differential relay arrangement, two similar current transformers are connected at either end of the system element under protection (such as a feeder) by means of pilot wires. The relays are connected in series with the pilot wires, one at each end. The relative polarity of the CTs
Voltage Balance Differential Relay Read More »
Mho Type Distance Relay – Working and Characteristics: Mho relay is a high speed relay and is also known as admittance relay. It is also sometimes called an angle impedance relay. In this Mho type distance relay operating torque is obtained by the volt-ampere element and the restraining torque is developed due to the voltage
Mho Type Distance Relay – Working and Characteristics Read More »
Universal Relay Torque Equation Derivation: Universal Relay Torque Equation – Most of the protection relays consist of some arrangement of electromagnets. These electromagnets have either current windings or voltage windings and in some cases both the windings. Currents through the windings produce magnetic fluxes and the torque is produced by interaction between the fluxes of
Universal Relay Torque Equation Derivation Read More »
