Residual current relay uses residual current transformer to detect residual current and prevent electrical fire

Encore Wang Chong

0： summary

With the rapid development of social economy , The degree of social electrification is increasing , Electricity safety has become an important research topic . The common short circuit between phases can produce a large current , Switch protection can be used , And the human body gets an electric shock 、 The fire caused by current leakage caused by line aging and the grounding fault of equipment are caused by leakage current , The leakage current is generally at 30mA-3A, These values are very small , Traditional switches cannot protect , Therefore, it is necessary to adopt residual current action protection device . 

1： Residual current relay Application Introduction

Residual current relay detects residual current by residual current transformer , And under the specified conditions , When the residual current reaches or exceeds the given value , A switching device that makes the contacts in one or more electrical output circuits of an electric appliance open and close .

Here are three common leakage conditions .

1、 Protection against direct contact electric shock requires I△n≤30mA High sensitivity RCD. 

2、 Protection against indirect contact electric shock can be I△n Greater than 30mA Medium sensitivity RCD. 

3、 Fire prevention RCD To be used 4 Wood and or 2 Wood and RCD. 

about IT System , Residual current relay shall be used as specified . In order to prevent system insulation from decreasing and act as backup protection for secondary fault , According to the wiring type , A similar  TT  or  TN System protection measures . Firstly, insulation monitoring device shall be used , Predict a failure . 

about TT System , Residual current relay is recommended . Because when a single-phase ground fault occurs , The fault current is very small , And more difficult to estimate , The action current of the switch cannot be reached , Hazardous voltages will appear on the enclosure . here N The line needs to pass through the residual current transformer . 

about TN-S System , Residual current relay can be used , Fast sensitive cut-off fault , To improve safety and reliability , here  PE The wire shall not pass through the transformer ,N The wire needs to pass through the transformer , And shall not be repeatedly grounded .  

about TN-C System , Residual current relays shall not be used . because  PE  Line and  N  Line in one , if  PEN The wire is not repeatedly grounded , When the enclosure is charged , The incoming and outgoing currents of the transformer are equal ,ASJ Refuse to move ; if PEN The wire is repeatedly grounded , Part of the single-phase current will flow into the repeated grounding , After reaching a certain value ,ASJ Misoperation .  Need to TN-C The system was transformed into TN-C-S System , Same as TN-S System , Then connect the residual current transformer to TN-S In the system .

2： Ancorey electric ASJ Product Brief

Ancorey electric ASJ Series residual current relay can meet the protection requirements of the above leakage conditions , Used in conjunction with remote trip switch , Cut off the power supply in time , Prevent indirect contact 、 Limit leakage current . It can also be directly used as a signal relay , Monitor power equipment . Especially suitable for schools 、 Commercial buildings 、 Factory workshop 、 market 、 Industrial and mining enterprises 、 National fire protection unit 、 Intelligent building and community , metro 、 Petroleum chemical industry 、 Security protection of electricity used by telecommunications and national defense departments .

ASJ There are two main installation methods for series products ,ASJ10 Series for guide rail installation .

ASJ20 Series is panel mounted , The appearance and functions are shown in the table below ：

        

among AC The type and A The difference between type a residual current relay is ：AC Type a residual current relay is a residual current relay that can ensure tripping for the residual sinusoidal AC current suddenly applied or slowly rising , It mainly monitors sinusoidal AC signal .A Type a residual current relay is a residual current relay that can ensure tripping for the suddenly applied or slowly rising residual sinusoidal AC current and residual pulsating DC current , It mainly monitors sinusoidal AC signal and pulse DC signal . 

3： Project introduction

A large stadium in a foreign country is purchased by a complete set factory in China 840 Residual power distribution cabinet , purchase ASJ20-LD1A Residual current relay 1100 The rest , The complete set factory shall uniformly complete the assembly 、 connection 、 test , packing .   

There are three capacity specifications for the on-site distribution cabinet , Respectively 22kVA、75kVA、150kVA, among 22kVA and 150kVA Capacity specifications are divided into single channel and double channel , The specific quantity is shown in the table below ：

 

ASJ Series of residual current relay products can monitor the leakage current in the line , When the leakage current reaches or exceeds the set value , Internal relay action , Give an alarm , And can be linked with the circuit breaker switch , Cut off the line quickly , Ensure line safety ,ASJ Application of series residual current relay , It provides a guarantee for the safe use of electricity for the stadium .