摘 要：分析低压开口式电流互感器的原理，结合工程实例分析开口电流互感器在低压配电系统中，主要是改造项目中的应用及施工细节，为用户快速实现智能配电提供解决方案，该方案具有成本低、投资少、安装接线简便等优点，有利于低压智能配电的进一步推广和应用。

Abstract: this paper analyzes the principle of low voltage split core current transformer, analyzes the application and construction details of split core current transformer in low voltage distribution system with engineering examples, and provides a solution for users to realize intelligent distribution quickly. The scheme has the advantages of low cost, low investment and simple installation and wiring, which is beneficial to the further popularization and application of low voltage intelligent distribution.

关键词：开口式电流互感器；低压配电系统；改造项目；工作原理；应用；施工细节

Keywords: Split core current transformer; Low Voltage Distribution System; Renovation Project; Principle; Application; Construction Details

1.引言 Introduction

目前市场大部分低压电流互感器主要用于新项目的建设，由于经济的飞速发展，企业对节能减排意识逐渐提高，许多企业的电气特点是： 

At present, most of the low voltage current transformers in the market are mainly used in the construction of new projects. Due to the rapid development of economy, the awareness of energy saving and emission reduction is gradually improved. The electrical characteristics of many enterprises are:

1)电气柜运行的时间长；

2)大部分电流互感器只是对系统电流进行测量，也没有相应的计量装置和保护装置，计量装置只有一块供电局的总表，而对所有车间电能无法进行考核，系统线路保护装置根本没有；

3)大部分线路干线为大规格铜排，拆卸需要大量的人力和时间，安装常规电流互感器不方便；

4)企业生产时间比较紧迫，不能长时间停电。

所以如需对上述电气进行改造，采用开口式电流互感器可以为用户节约大量的投资。

1）Long running time of electric gas cabinet;

2）Most of the current transformers only measure the current of the system, and there is no corresponding metering device and protection device. The measuring device has only one master table of the power supply bureau, but the electric energy of all workshops can not be assessed, and the system line protection device is not available at all,;

3）Most of the main lines are large size copper bar, it takes a lot of manpower and time to disassemble, it is not convenient to install conventional current transformer;

4）Enterprise production time is more urgent, can not long time blackout.

Therefore, the use of split core current transformer can save a lot of investment for users.

2.产品设计Product design

1）结构特点 Structural characteristics

我司开口互感器型号齐全，有线缆专门用的圆孔互感器，有适用于铜排的方孔互感器，本产品外壳材料采用PC/ABS合金，具有耐高温、机械强度高、环保等特点；铁芯采用有取向冷扎硅钢片，具有性能稳定，机械强度高，导磁率较高等特点；具体结构如图1所示。

Our company has a complete range of split core current transformer models, including round hole transformers for cables, and square hole transformers for copper bars., this product shell material is PC/ABS alloy, with high temperature resistance, high mechanical strength, environmental protection and other characteristics; The core adopts oriented cold bonded silicon steel sheet with stable performance, high mechanical strength and high magnetic conductivity.

图1（方孔型，适用于铜排） Figure.1

骨架线圈，2-透明翻盖，3-安装螺母，4-接线端子，5-铁芯，6-弹簧，7-外壳，8-安装螺钉。

1-Skeleton coil ,2-transparent flip ,3-mount nut ,4-wiring terminal ,5-core ,6-spring ,7-shell ,8-mount screw.

2）开口电流互感器工作原理Working principle of open current transformer

开口低压电流互感器的工作原理如图1所示，开口电流互感器的一次绕组串联在被测线路中，I1为线路电流即电流互感器的一次电流，N1为电流互感器的一次匝数，I2电流互感器二次电流（通常为5A、1A），N2为电流互感器的二次匝数，Z2e为二次回路设备及连接导线阻抗。当一次电流从电流互感器P1端流进，P2端出，在二次Z2e接通的情况下，由电磁感应原理，电流互感器二次绕组有电流I2从S1流过，经Z2e至S2，形成闭合回路。由此可得电流在理想状态下I1×N1=I2×N2，所以有I1/I2=N1/N2=K，K为电流互感器的变比。但是由于开口式电流互感器的铁芯切开后，使铁芯的性能下将的比较厉害，所以须将互感器的铁芯截面积加大，而且提高安匝数，将I1×N1=I2×N2≥100AN。

The working principle of the  low voltage split core current transformer is shown in figure 1, The primary winding of the split core current transformer is connected in series in the line under test, I1 is the primary current of the current transformer, N1 is the primary turn of the current transformer, I2 current transformer secondary current (usually 5 A、1A), N2 is the secondary turns of the current transformer, Z2e for secondary circuit equipment and connection wire impedance. As the primary current flows through the P1 end of the current transformer, P2 out, If the secondary Z2e is connected, Based on electromagnetic induction, The secondary winding of the current transformer has current I2 flowing through the S1, Z2e to S2, Form a closed loop. Hence the I1×N1=I2×N2, of current in ideal state And so there's I1/I2=N1/N2=K, K is the ratio of current transformer. But since the core of the open current transformer is cut, Make the core performance will be more powerful, So the cross section of the transformer core must be increased, And increase the number of turns, I1×N1=I2×N2≥100 AN.

图2 Figure.2

注：图2中1-开口电流互感器的上体，2-开口电流互感器的下体，3-安装螺丝、螺母。

Note: Figure 2- Upper body of the 1- Open current transformer ,2- Lower body of the 2- Open current transformer ,3- Install screws, nuts

3）产品安装Product installation

如图2所示，将互感器的安装螺丝、螺母打开，卸下互感器的下体，将互感器的上体装入配电系统的一次母排，合上互感器的下体，将互感器的安装螺丝穿过互感器上、下体的固定孔，拧上螺母，将互感器的上、下体固定在一起，然后将互感器通过互感器两侧的安装固定孔将互感器固定在母排上，完成互感器的安装。然后将互感器的二次接到测量装置。整个过程比较快速简单。       

As shown in figure 2, the installation screws and nuts of the transformer are opened, the lower body of the transformer is unloaded, the upper body of the transformer is loaded into the primary bus row of the distribution system, the lower body of the transformer is closed, the installation screw of the transformer passes through the fixed hole of the upper and lower body of the transformer, the nut is screwed, the upper and lower body of the transformer is fixed together, and then the transformer is fixed on the bus row through the installation fixing hole on both sides of the transformer to complete the installation of the transformer. Then connect the secondary of the transformer to the measuring device. The whole process is relatively fast and simple.

3.应用 Applications

开口电流互感器主要应用在低压配电改造项目中，开口式电流互感器同常规闭口互感器一样输出为标准的5A或1A，测量精度高，容量大，可与测量仪器、仪表配套使用，部分产品过载能力强可与装置配套使用。

Split core current transformer is mainly used in the low voltage distribution transformation project. Split core current transformer is output as standard 5 A or 1 A, as the conventional closed current transformer. The measuring precision is high and the capacity is large.

越南美的工厂为例如图3所示，每条线均需测量三相电流,将采集的电流信号供给电能表DTSD1352，组网之后数据传输到美的工业云系统。A相、B相、C相的可以选择我们的圆孔型开口互感器，每相额定电流为400A,采用AKH-0.66/K K-∮36 400/5开口电流互感器采集电流信号。现场无需拆线或者铜排。

For example, as shown in figure 3, each line needs to measure three-phase current, supply the collected current signal to the watt-hour meter DTSD1352, transmit the data to the industrial cloud system of the United States after networking. A phase, B phase, C phase can choose our round hole type open transformer, each phase rated current is 400 A, adopt AKH-0.66/K K-∮36 The 400/5 split core current transformer collects current signals.There is no need to remove wires or copper bars on site.

图3 Figure.3

4.结束语Summary

开口式电流互感器已经成熟的在多个国家工矿企业工程配电监控系统中得到应用，降低了投资成本，提供工作效率及减轻工作难度。

Split core current transformer has been used in the engineering distribution monitoring system of industrial and mining enterprises in many countries, which reduces the investment cost, provides the working efficiency and reduces the working difficulty.

参考文献 Bibliography

1.Solutions For Enterprise Micro-grid System 2020.02

安科瑞 缪阳扬