Industrial 0.4kV Protector--ASJ Residual Current Protection Relay

Residual Current Protection Relay Principle and Application

Residual Current Protection Relay, used as main or backup protection in low-voltage distribution systems, plays an important role in eliminating harm to the human body or fire hazards. Correct use of residual Current Protection Relay and understanding its principles are of great significance to ensuring the safe and reliable operation of electrical systems. In TT systems, residual Current Protection Relay is used for earth fault protection; whereas in TN systems, instantaneous and leakage protection already meet the sensitivity requirements for earth fault protection.

Residual Current Protection Relay is a device that detects residual current, compares the residual current value with a reference value, and when the residual current value exceeds the reference value, issues a mechanical opening and closing signal (to trip the mechanical switchgear or trigger an auditory and visual alarm device).

Residual Current Protection Relay is usually combined with low-voltage circuit breakers or low-voltage contactors to form combined-type residual current protection devices. They are mainly used in distribution circuits of TT and TN systems with AC 50Hz, rated voltage 400V and below for earth fault protection of electrical lines, to prevent equipment damage and electrical fire accidents caused by earth fault currents. They can also provide indirect contact protection against electric shock hazards to human body, and are widely applied in power distribution systems of intelligent buildings.

ASJ Intelligent Residual Current Protection Relay

ASJ series residual Current Protection Relay can be combined with low-voltage circuit breakers or low-voltage contactors to form combined-type residual current protection devices. They are mainly suitable for AC 50Hz, rated voltage 400V and below for TT and TN system distribution circuits, used for earth fault protection of electrical lines, preventing equipment damage and electrical fire accidents caused by earth fault currents. They can also provide indirect contact protection against electric shock hazards.

ASJ Series Residual Current Protection Relay Models

• ASJ10-LD1C basic functions include: AC type residual current measurement, current over-limit alarm indication, adjustable rated residual operating current, adjustable non-actuating time limit, two sets of relay outputs, local and remote "test", "reset" functions, A type residual current measurement, and current percentage bar graph display.

• ASJ10-LDIA functions include: adjustable rated residual operating current, adjustable non-actuating time limit, two sets of relay outputs (adjustable), local and remote "test", "reset" functions, A type residual current measurement, adjustable rated residual operating current, adjustable non-actuating time limit, and two sets of relay outputs (adjustable).

• ASJ10L-LDIA 12 residual Current Protection Relay, main functions include: adjustable transformer disconnection alarm, adjustable pre-alarm value, adjustable return value, local and remote "test", "reset" functions, LCD display, 25 event records, AC type residual current measurement, and current over-limit alarm indication.