Fixed time overcurrent protection principle wiring diagram

What is Buchholz Relay in Transformer ?Buchholz relay is a gas relay used in oil-immersed transformers to monitor the gas production inside the transformer, so as to detect possible faults inside the transformer.How Buchholz relays workThe Buchholz relay works on the basis of the gas produced when the transformer fails internally. When overheating or discharge failure occurs inside the transformer, gas is produced. These gases will rise and pass through the top of the tank into the oil storage t

What is a Backup Relay ?Backup Relay DefinitionA backup relay is an additional relay system that operates if the main relay fails, ensuring continued protection.Function of Backup RelayThe primary function of a backup relay is to trip the circuit breaker when the main relay fails.Reasons for Main Relay FailureMain relays can fail due to mechanical defects, power supply issues, or problems in the CT/PT circuits.Importance of Backup RelayBackup relays provide an extra layer of reliability, essenti

What is an Electromagnetic Relay ?Electromagnetic Relay DefinitionAn electromagnetic relay is a switch that uses an electromagnet to mechanically operate a switching operation, essential in various electrical protection systems.Operation PrinciplesThe working of electromagnetic relays involves principles like magnitude and ratio measurement, essential for understanding their functionality in electrical systems.Types of Relays Attracted Armature type relay Induction Disc type relay Induction Cup

What is Protective Relay ?Protective Relay DefinitionA protective relay is an automatic device that senses abnormal conditions in electrical circuits and triggers actions to isolate faults.Types of Protective Relays Definite time relays Inverse time relays with definite minimum time(IDMT) Instantaneous relays IDMT with inst Stepped characteristic Programmed switches Voltage restraint over current relayOperating PrinciplesProtective relays operate by detecting abnormal signals, with specific pick

What is Differential Relay?Differential Relay DefinitionA differential relay is defined as a device that responds to the difference between two or more similar electrical quantities, such as currents or voltages, to detect faults.Principle of OperationThese relays activate based on discrepancies in electrical quantities within the protected zone, ensuring accurate fault detection.Types and ConfigurationsDifferential relays vary mainly into current and voltage balance types, each tailored for spe

What is an Instantaneous Relay ?Instantaneous Relay DefinitionAn instantaneous relay is defined as a relay that operates with no intentional delay when the current exceeds a set threshold.No Intentional DelayInstantaneous relays activate without any added delay, making them very fast in operation.Inherent DelaysThese relays still have minor delays due to electrical and mechanical factors, but they are not intentionally introduced.Types of Instantaneous RelaysExamples include attracted armature r

What is a Thermal Relay?Thermal relay definitionA thermal relay is defined as a device that uses unequal expansion rates of metals in a bimetallic strip to detect overcurrent conditions.Working principleThermal relays work by heating a bimetallic strip, causing it to bend and close the normally open contact, which triggers the circuit breaker.Construction of thermal relayIt consists of a bimetallic strip, metal with different expansion coefficients, a heating coil and contacts.Technical paramete

What is a Latching Relay ?Latching Relay DefinitionA latching relay is a type of relay that maintains its contact position without continuous power application, allowing for efficient control of circuits.Circuit DiagramThe latching relay circuit diagram shows how Button-1 and Button-2 control the energizing and de-energizing of the relay, respectively.Operation MechanismBy pressing Button-1, the relay is energized and remains so even after the button is released, until Button-2 is pressed.Effici

Intermediate relay self-locking secondary control circuit