摘要：本文通过对海洋平台接地故障的分析，论述了海洋平台手持式和移动式用电设备安装漏电保护器的必要性，同时简述了漏电保护器的工作原理。
Abstract: Through the analysis of the ground fault of the ocean platform, this paper discusses the necessity of installing the leakage protector on the handheld and mobile electrical equipment of the ocean platform, and briefly describes the working principle of the leakage protector.
关键词：海洋平台；IT系统；漏电保护器
Keywords: Ocean platform; IT system; leakage protector
0：概述 Overview
在海洋石油及天然气开采过程中，海洋平台作为油气采集、临时存储及简单处理的重要场所，其危险性极大。同时，受日晒雨淋、盐雾侵蚀、用电设备紧凑及操作空间狭小等诸多因素的影响，海洋平台的电气安全一直存在隐患。为了避免海洋平台电气安全事故的发生，需要根据海洋平台的环境特点，因地制宜地选择供配电系统接地形式，并选择相应的接地保护方式。
In the process of ocean oil and natural gas exploitation,ocean platform are extremely dangerous as important places for oil and gas collection, temporary storage and simple processing. At the same time, affected by many factors such as sun and rain, salt spray erosion, compact electrical equipment, and narrow operating space, there are always hidden dangers in the electrical safety of ocean platform. In order to avoid electrical safety accidents of ocean platform, it is necessary to select the grounding form of the power supply and distribution system according to the environmental characteristics of the ocean platform, and choose the corresponding grounding protection method.
1：海洋平台配电系统的特点
The characteristics of the power distribution system of the ocean platform
低压配电系统分TN系统、TT系统及IT系统3种形式。每种接地形式的低压配电系统都有其自身的优缺点和适用范围。设计工作者应根据作业场所的环境条件、用电设备的特点和用电要求等因素加以具体选择。当前，海洋平台一般使用IT系统供电，这是由其自身的特点决定的：1）海洋平台远离陆地，对不间断供电的要求高。例如平台的消防措施和紧急逃生设施就不允许断电；2）海洋平台环境恶劣，盐雾和潮湿容易使用电设备和供电线路的绝缘损坏，出现接地故障。
The low-voltage power distribution system is divided into three forms:the TN system,the TT system and the IT system.Each type of grounding low-voltage power distribution system has its own advantages, disadvantages and scope of application. Designers should make specific choices based on factors such as the environmental conditions of the workplace, the characteristics of electrical equipment, and electrical requirements. At present, ocean platform generally use IT systems for power supply, which is determined by their own characteristics: 1) ocean platforms are far away from the land and require high uninterrupted power supply. For example, the platform's fire protection measures and emergency escape facilities are not allowed to be powered off; 2) The marine platform has a harsh environment, salt spray and humidity are prone to damage to the insulation of electrical equipment and power supply lines, and ground faults occur.
2：海洋平台手持式和移动式用电设备漏电保护问题
Leakage protection of handheld and mobile electrical equipment on ocean platforms
1）海洋平台手持式和移动式用电设备发生接地故障一般有以下原因；a)手持式和移动式用电设备由于需要频繁移动，电缆与用电设备的接头容易松脱，使相线碰设备外壳而发生接地故障；b)手持式和移动式用电设备在使用过程中电缆反复弯曲，使芯线部分折断，刺破电缆绝缘与外部可导电部分接触而发生接地故障。
Ground faults of handheld and mobile electrical equipment on ocean platforms are generally due to the following reasons; a) Hand-held and mobile electrical equipment need to be moved frequently, so the cable and electrical equipment’s joints are easy to loosen, causing the phase lines to touch. Ground fault occurs on the equipment shell; b) The cable repeatedly bends during the use of handheld and mobile electrical equipment, causing the core wire to be broken, piercing the cable insulation and contacting the external conductive part to cause a ground fault.
2）海洋平台手持式和移动式用电设备接地故障分析
Ground fault analysis of handheld and mobile electrical equipment on ocean platforms
a)单相接地故障。国际电工委员会标准IEC4.79(电流通过人体的效应)确定，通过人体的交流50Hz电流不超过30mA时，人体不会发生心室纤维性颤动而死亡，它与人体潮湿程度、接触电压高低没有直接关系。大多数海洋平台低压配电系统接地形式一直沿用中性点不接地的IT系统，这样如果发生直接触及单相带电导体、单相接地或者间接触点故障时，单相接地故障电流为另外两相对地电容电流的向量和，通常两相对地电容电流的向量和很小，即故障电流很小，这种情况下不会构成电击危险，因此也可以不切断供电电源。但是，随着海洋平台用电设备的增多，电力电缆线路随之增多，电容电流相应的增大，发生故障时单相接地电流也随之增大。如果用电设备的外壳没有可靠接地或者接地线断开时，单相接地故障电流只能通过人体形成回路，当通过人体的交流50Hz电流超过30mA时，人体就可能会因发生心室纤维性颤动而死亡。在低压配电系统中，用电设备的一相绝缘击穿，使其设备外壳带电。当单相接地故障电流Id=Ia+Ib≥30mA时，就超过了人体能承受的交流电流安全阈值，一定要立即切断供电以确保安全。此时在用电设备处安装漏电保护器是唯一的解决办法
Single-phase ground fault. The International Electrotechnical Commission standard IEC4.79 (Effect of current passing through the human body) determines that when the AC 50Hz current through the human body does not exceed 30mA, the human body will not die due to ventricular fibrillation. It has no direct relationship with the humidity of the human body and the level of contact voltage.Most of the low-voltage power distribution systems of ocean platforms have always used IT systems with ungrounded neutral points, so that if direct contact with single-phase live conductors, single-phase grounding or indirect contact failure occurs, the single-phase grounding fault current is the other two relative.The vector sum of the ground capacitance current is usually very small, that is, the fault current is very small. In this case, there is no danger of electric shock. Therefore, the power supply may not be cut off. However, as the number of electrical equipment used on ocean platforms increases, power cable lines increase accordingly, and the capacitive current increases accordingly, and the single-phase ground current also increases when a fault occurs. If the shell of the electrical equipment is not reliably grounded or the grounding wire is disconnected, the single-phase ground fault current can only form a loop through the human body. When the AC 50Hz current through the human body exceeds 30mA, the human body may be caused by ventricular fibrillation. die. In the low-voltage power distribution system, one-phase insulation breakdown of electrical equipment causes the equipment shell to become live. When the single-phase ground fault current Id=Ia+Ib≥30mA, it exceeds the safety threshold of AC current that the human body can withstand, and the power supply must be cut off immediately to ensure safety. At this time, installing a leakage protector at the electrical equipment is the only solution.叫
b)异相接地故障。当发生单相接地故障时，另外两相对地电压升高，电气设备的绝缘要求承受较高的电压，可能会导致绝缘破坏使故障进一步扩大，照成异相接地故障的发生。根据《低压配电设计规范》GB50054-1995中第4.4.14条：IT系统外露可导电部分可用共同的接地极接地，亦可个别地或成组地用单独的接地极接地。当外露可导电部分为共同接地，则发生第二次异相接地故障时，故障回路的切断应符合TN系统接地故障保护的要求。海洋平台是钢结构体，本身就是导体，相当于用电设备外露可导电部分共用接地极接地。当发生异相接地故障时，故障回路的切断应符合TN系统接地故障保护的要求。按照规范要，在TN系统中，手持式和移动式用电设备应设置漏电保护器。
Out-of-phase grounding fault. When a single-phase grounding fault occurs, the other two phase-to-ground voltages increase, and the insulation of electrical equipment is required to withstand a higher voltage, which may cause insulation damage and further enlarge the fault, which will result in an out-of-phase grounding fault. According to Article 4.4.14 of "Code for Low-Voltage Power Distribution Design" GB50054-1995: The exposed conductive parts of the IT system can be grounded with a common grounding electrode, or individually or in groups with separate grounding electrodes. When the exposed conductive parts are grounded together, when the second out-of-phase ground fault occurs, the cut-off of the fault circuit should meet the requirements of TN system ground fault protection. The offshore platform is a steel structure, which itself is a conductor, which is equivalent to the common grounding electrode of the exposed conductive parts of the electrical equipment. When an out-of-phase ground fault occurs, the disconnection of the fault circuit should meet the requirements of TN system ground fault protection. According to the specifications, in the TN system, handheld and mobile electrical equipment should be equipped with leakage protectors.
3. 产品概述 product description
剩余电流继电器是由剩余电流互感器来检测剩余电流，并在规定条件下，当剩余电流达到或超过给定值时，使电器的一个或多个电气输出电路中的触点产生开闭动作的开关电器。
下面介绍三种常见的漏电情况。
The residual current relay is a residual current transformer to detect the residual current, and under specified conditions, when the residual current reaches or exceeds a given value, one or more electrical output circuit contacts in the electrical appliance will open and close. Switch electrical appliances.
Here are three common leakage situations.
1、防直接接触电击必须采用I△n≤30mA的高灵敏度的RCD。
High-sensitivity RCD with I△n≤30mA must be used to prevent direct contact and electric shock.
2、防间接接触电击可采用I△n大于30mA的中灵敏度的RCD。
The medium sensitivity RCD with I△n greater than 30mA can be used to prevent indirect contact and electric shock.
3、防火RCD需采用4极或2极RCD。
A 4-pole or 2-pole RCD shall be used for fireproof RCD.
对于IT系统，按规定采用剩余电流继电器。为防止系统绝缘降低和作为二次故障后备保护，依据接线型式，采用类似 TT 或 TN 系统的保护措施。首先应采用绝缘监视装置，预测一次故障。
For the IT systems, residual current relays are used as required. In order to prevent the insulation of the system from degrading and as a secondary fault backup protection, according to the wiring type, a protective measure similar to the TT or TN system is adopted. First, an insulation monitoring device should be used to predict a failure.
对于TT系统，推荐采用剩余电流继电器。因为当发生单相接地故障时，故障电流很小，且较难估计，达不到开关的动作电流，外壳上将出现危险电压。此时N线必须穿过剩余电流互感器。
For the TT system, a residual current relay is recommended. Because when a single-phase ground fault occurs, the fault current is very small and difficult to estimate. If the operating current of the switch is not reached, a dangerous voltage will appear on the housing. At this time, the N wire must pass through the residual current transformer.
对于TN-S系统，可采用剩余电流继电器。更快速灵敏切断故障，以提高安全可靠性，此时 PE 线不得穿过互感器，N 线必须穿互感器，且不得重复接地。
For the TN-S system, a residual current relay can be used. Cut off the fault more quickly and sensitively to improve safety and reliability. At this time, the PE wire must not pass through the transformer, and the N wire must pass through the transformer, and it must not be grounded repeatedly.
对于TN-C系统，不能采用剩余电流继电器。因为 PE 线和 N 线合一，若 PEN 线不重复接地，当外壳带电，互感器进出电流相等，ASJ拒动；若PEN线重复接地，部分单相电流将流入重复接地，达一定值后，ASJ 误动。 需将TN-C系统改造成TN-C-S系统，同TN-S系统，再将剩余电流互感器接入TN-S系统中。
For the TN-C systems, residual current relays cannot be used. Because the PE wire and the N wire are integrated, if the PEN wire is not repeatedly grounded, when the shell is energized, the current in and out of the transformer is equal, and the ASJ refuses to move; if the PEN wire is repeatedly grounded, part of the single-phase current will flow into the repeated grounding. After reaching a certain value, ASJ malfunctioned. It is necessary to transform the TN-C system into a TN-C-S system, which is the same as the TN-S system, and then connect the residual current transformer to the TN-S system.
4.产品简介 Product Introduction
安科瑞电气ASJ系列剩余电流继电器能够满足上述几种漏电情况的防护，与遥控跳闸开关联用，及时切断电源，防止间接接触、限制漏电电流。也可以直接作为信号继电器，监控电力设备。特别适用于学校、商厦、工厂车间、集贸市场、工矿企业、国家重点消防单位、智能大厦与小区，地铁、石油化工、电信及国防等部门用电的安全保护。
Acrel Electric's ASJ series residual current relay can meet the protection of the above-mentioned leakage conditions, and it can be used in conjunction with a remote trip switch to cut off the power supply in time to prevent indirect contact and limit the leakage current. It can also be directly used as a signal relay to monitor power equipment. It is especially suitable for the safety protection of electricity consumption in schools, commercial buildings, factory workshops, bazaars, industrial and mining enterprises, national key fire protection units, smart buildings and communities, subways, petrochemicals, telecommunications and national defense departments.
ASJ系列产品主要有两种安装方式，ASJ10系列为导轨安装，外形和功能如下表所示：
The ASJ series products mainly have two installation methods. ASJ10 series are rail-mounted installations. The appearance and functions are shown in the following table:
ASJ20系列为面板安装，外形和功能如下表所示：
ASJ20 series are panel mounted, the appearance and functions are shown in the following table:
其中AC型和A型剩余电流继电器的区别是：AC型剩余电流继电器是对突然施加或缓慢上升的剩余正弦交流电流能确保脱扣的剩余电流继电器，主要监测正弦交流信号。A型剩余电流继电器是对突然施加的或缓慢上升的剩余正弦交流电流和剩余脉动直流电流能确保脱扣的剩余电流继电器，主要监测正弦交流信号和脉冲直流信号。
Among them, the difference between AC type and A type residual current relay is: AC type residual current relay is a residual current relay that can ensure the tripping of the residual sinusoidal alternating current that is suddenly applied or slowly rising, and it mainly monitors sinusoidal alternating current signals. Type A residual current relay is a residual current relay that can ensure the tripping of residual sinusoidal alternating current and residual pulsating direct current that is applied suddenly or slowly, and mainly monitors sinusoidal alternating current signals and pulsed direct current signals.
仪表具体的接线端子和典型接线如下所示：
The specific wiring terminals and typical wiring of the instrument are as follows:
5.结语 Conclusion
以往海洋平台的电气设计中，对于手持式和移动式用电设备的配电保护，基本没有或很少装设漏电保护器，更有设计者认为，在海洋平台的IT供电系统中手持式和移动式用电设备没有必要装设漏电保护器，从上看来，这种想法只是考虑了其中的一个方面，是片面的。ASJ系列剩余电流继电器产品能够监测线路中的漏电流，当漏电流达到或者超过设定值时，内部继电器动作，发出告警，并能与断路器开关联动，快速切断线路，保证线路安全。
In the previous electrical design of ocean platforms, there were basically no or seldom installed leakage protectors for the power distribution protection of handheld and mobile electrical equipment. More designers believe that in the IT power supply system of ocean platforms, handheld and it is not necessary to install a leakage protector for mobile electrical equipment. From the above point of view, this idea only considers one aspect of it and is one-sided. ASJ series residual current relay products can monitor the leakage current in the line. When the leakage current reaches or exceeds the set value, the internal relay will act to issue an alarm, and can be linked with the circuit breaker switch to quickly cut off the line to ensure line safety.
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