安科瑞ASJ剩余电流继电器在马尔代夫某发电机组项目上的应用

 Application of ASJ Residual Current Relay in a Generator Set Project in Maldives 

摘要：分析了剩余电流继电器的必要性，介绍了ASJ剩余电流继电器的主要功能、工作原理、分类情况和提出了在选择剩余电流保护断路器时的原则和注意事项。现就马尔代夫某发电机组项目加装我司剩余电流继电器做一简要介绍。

Abstract: the necessity of applying residual current, the main functions, working principle, classification situation of ASJ residual current relay are introduced, and the principles and precautions in selecting residual current protection circuit breaker are indicated. This is a brief introduction about the addition of our company application of ASJ residual current relay in a generator set project in Maldives.

关键词：ASJ剩余电流继电器；发电机组；应用。

Keywords: ASJ residual current relay; generator set; application.

1.项目概述 Project overview

本项目位于马尔代夫，安装剩余电流继电器是为了检测剩余电流，将剩余电流值与基准值相比较，当剩余电流值超过基准值时，发出一个机械开闭信号（使机械开关电器脱扣或声光报警装置发出报警）。剩余电流继电器通常与低压断路器或低压接触器等组成组合式剩余电流保护装置，主要适用于交流50Hz，额定电压400V及以下的TT和TN系统配电线路，用来对电气线路进行接地故障保护，防止接地故障电流引起的设备损坏和电气火灾事故，也可用来对人身触电危险提供间接接触保护，因而低压供配电系统中广泛应用。

This project is located in Maldives. The purpose of the residual current relay installed is to detect the residual current and compare the residual current value with the base value. When the residual current value exceeds the base value, it will send out a mechanical on-off signal (to make the mechanical switch tripped or the acousto-optic alarm device send out an alarm).Residual current relay usually with low voltage circuit breaker or low voltage contactor, etc combined residual current protection device, mainly applied to ac 50 hz, rated voltage 400 v and below the TT and TN system distribution circuit, used to ground fault protection electric circuit, prevent equipment damage caused by ground fault current and electrical fire accident, also can be used to provide indirect contact to person get an electric shock risk protection, and therefore is widely used in low voltage power supply and distribution system.

2.剩余电流继电器主要用途 Main uses of residual current relay

2.1 间接接触电击保护 Protection of Indirect Contact Electric Shock 
间接接触电击保护的措施是自动切断电源。GB 13955“对间接接触电击事故的防护”规定：“间接接触电击事故防护的主要措施是采用自动切断电源的保护方式，以防止由于电气设备绝缘损坏发生损坏事故。当电路发生绝缘损坏造成接地故障。其故障电流值小于过电流保护装置的动作电流值时，应安装剩余电流保护装置。”研究表明，人体接触电压的安全值为 50 V。为保证人身安全，电气装置的任何部分发生绝缘故障时，一旦接触电压超过 50 V 时，需要在规定的时间内自动切断故障部分电源。过电流保护装置受电气线路和设备及自身动作值限制，不能自动切断电源。剩余电流保护装置不受负荷电流影响，可与过电流保护装置配合使用，作间接接触电击保护 。

The measure of indirect contact electric shock protection is to automatically cut off the power supply. GB 13955" the protection of indirect contact electric shock accident "stipulates :" the main measure of indirect contact electric shock accident protection is to adopt the protection mode of automatically cutting off the power supply to prevent the damage accident caused by the insulation damage of electrical equipment. When the circuit insulation damage caused by grounding fault. When the fault current value is less than the operating current value of the over-current protection device, the residual current protection device shall be installed ." According to the research, the safe value of contact voltage is 50V. For personal safety, when insulation failure occurs in any part of the electrical device, once the contact voltage exceeds 50V, it is necessary to automatically cut off the fault part of the power supply within the specified time. The over-current protection device is limited by the electrical circuit and equipment and its own action value, and can not automatically cut off the power supply. The residual current protection device is not affected by the load current and can be used in conjunction with the over-current protection device for indirect contact electric shock protection.

2.2 接地故障保护 Ground fault protection
接地是带电导体和大地、接地的金属外壳或与地有联系的构件之间的接触，其故障可能导致人身电击伤亡和设备损坏，严重时可能引发电气火灾。接地故障保护过去通常采用过电流保护装置进行保护，当接地故障电流大于过电流保护装置定值时，由过电流保护装置切断故障电路。

TT系统中额定电流较大、配电线路较长的线路，TN系统中带电导线落地接地故障、不安全的金属性接地故障、电弧性接地故障时，都有可能出现接地故障电流小于过电流保护动作整定电流，过电流保护装置不动作的情况。剩余电流保护装置，或带接地故障保护的断路器，能可靠地进行接地故障保护。

Grounding is the contact between a live conductor and the earth, a grounded metal shell or a component connected to the ground. Its failure may lead to personal electric shock casualties and equipment damage, and may cause electrical fire in serious cases. Ground fault protection used to be protected by over-current protection device. When the grounding fault current is greater than the fixed value of the over-current protection device, the fault circuit is cut off by the over-current protection device.

In TT system, the line with larger rated current and longer distribution line, grounding fault of live conductor, unsafe metallic grounding fault and arc grounding fault in TN system may occur that the grounding fault current is less than the setting current of over-current protection action, and the over-current protection device does not act. Residual current protection device, or circuit breaker with ground fault protection, can reliably carry out ground fault protection.

2.3 电气火灾保护 Electrical fire protection
电气火灾通常由电气短路引起，电气短路包括金属性短路和电弧性短路。前者是带电导体间（如相与相之间、相与 N 线之间）短路，多以高温熔焊金属为通路，故障电流以千安计，高温易使绝缘氧化而自燃，火灾危险虽大，但可用带短路保护的断路器和熔断器保护，由断路器瞬时动作切断电源，避免火灾。后者是带电导体对地短路，多以电弧为通路，故障电流虽小，但一方面电弧长时间延续，局部温度高，很容易点燃周边可燃物质，引发火灾；另一方面，又不足以使一般断路器动作跳闸切断电源。所以电弧性短路引起火灾危险远大于金属性短路。带剩余电流动作保护功能的断路器可在过电流保护装置不动作的情况下切断保障电路，防止电弧性短路引发的电气火灾。

Electrical fire is usually caused by electrical short circuit, which includes metal short circuit and arc short circuit. The former is a short circuit between live conductors (such as between phases, between phases and N lines). The fault current is calculated in kilo ampere. High temperature is easy to cause insulation oxidation and spontaneous combustion.

Although the fire hazard is great, it can be protected by circuit breakers and fuses with short circuit protection, and the power supply is cut off by instantaneous action of circuit breaker to avoid fire. The latter is a live conductor short circuit to the ground, mostly arc as the path, although the fault current is small, but on the one hand, the arc lasts for a long time, the local temperature is high, it is easy to ignite the surrounding combustible material and cause fire. Therefore, the fire hazard caused by arc short circuit is much greater than that of metal short circuit. The circuit breaker with residual current action protection function can cut off the support circuit without the operation of the over-current protection device to prevent the electrical fire caused by the arc short circuit.

3.ASJ系列剩余电流继电器 ASJ Series of Residual Current Relay

3.1 型号和功能  Model & Function