What is the use of stabilizing resistor in differential protection?

Stabilizing Resistor in High Impedance Differential Protection is used to prevent the operation of Relay in case of through fault. Through fault is a fault outside the zone of protection.

Why are resistors so important?

Resistors ensure components receive the proper voltage by creating a voltage drop, and they can protect a component from voltage spikes. If a component in your circuit requires less voltage than the rest of your circuit, a resistor will create a voltage drop to ensure the component does not receive too much voltage.

Why Metrosil is used in ref protection?

Metrosil is used to limit the peak voltage developed by the current transformer (CT) under internal fault conditions to a value below the insulation level of the CT, relay and interconnecting leads.

What is the purpose of ref relay?

The limit of the Restricted Earth Fault (REF) protection zone is defined by the location of the CTs. The relay is connected to the current transformers in such a way as to measure the difference in earth fault current ‘entering’ the protected zone with that ‘leaving’ the protected zone.

What is Metrosil resistor?

Metrosil offers a wide range of high energy silicon carbide varistors. These non-linear resistors provide surge protection for prestigious infrastructural projects. Our brand name is so well known, it is often used as a generic term for a varistor.

What are the essential qualities of protective relaying?

What are the Essential Qualities of Protective Relay?

• Reliability.
• Speed and Time.
• Sensitivity.
• Selectivity and discrimination.
• Stability.
• Simplicity.
• Economy.
• Adequateness.

What is ref and SEF protection?

It is backup protection for restricted earth fault (REF) relay. It operates the CB when REF is failed to trip the circuit, Heavy earth fault outside of the REF protective Zone, and all other earth faults. Simply we can say, it is standby protection for all other earth faults.

What is meant by high impedance?

Hi-Z (or High-Z or high impedance) refers to an output signal state in which the signal is not being driven. The signal is left open, so that another output pin (e.g. elsewhere on a bus) can drive the signal or the signal level can be determined by a passive device (typically, a pull-up resistor).

Why do we use NCT?

Noncontact Tonometry : Noncontact (or air-puff) tonometry does not touch your eye but uses a puff of air to flatten your cornea to measure intraocular pressure. It is often used as a simple way to check for high IOP and is the easiest way to test children.

How does a Metrosil work?

Metrosil CTPU It acts as a passive load and draws little current, thus preventing inaccuracies in the measurement of the CT. During open circuit conditions, the varistor is subjected to an applied current and acts as an active load, limiting the voltage across the CT terminals and preventing any damage.