摘 要：分析低壓開口式電流互感器的原理，結合工程實例分析開口電流互感器在低壓配電系統中，主要是改造項目中的應用及施工細節，為用戶快速實現智能配電提供解決方案，該方案具有成本低、投資少、安裝接線簡便等優點，有利于低壓智能配電的進一步推廣和應用。

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.

關鍵詞：開口式電流互感器；低壓配電系統；改造項目；工作原理；應用；施工細節

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

1.引言 Introduction

目前市場大部分低壓電流互感器主要用于新項目的建設，由于經濟的飛速發展，企業對節能減排意識逐漸提高，許多企業的電氣特點是： 

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)電氣柜運行的時間長；

2)大部分電流互感器只是對系統電流進行測量，也沒有相應的計量裝置和保護裝置，計量裝置只有一塊供電局的總表，而對所有車間電能無法進行考核，系統線路保護裝置根本沒有；

3)大部分線路干線為大規格銅排，拆卸需要大量的人力和時間，安裝常規電流互感器不方便；

4)企業生產時間比較緊迫，不能長時間停電。

所以如需對上述電氣進行改造，采用開口式電流互感器可以為用戶節約大量的投資。

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.產品設計Product design

1）結構特點 Structural characteristics

我司開口互感器型號齊全，有線纜專門用的圓孔互感器，有適用于銅排的方孔互感器，本產品外殼材料采用PC/ABS合金，具有耐高溫、機械強度高、環保等特點；鐵芯采用有取向冷扎硅鋼片，具有性能穩定，機械強度高，導磁率較高等特點；具體結構如圖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.

圖1（方孔型，適用于銅排） Figure.1

骨架線圈，2-透明翻蓋，3-安裝螺母，4-接線端子，5-鐵芯，6-彈簧，7-外殼，8-安裝螺釘。

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

2）開口電流互感器工作原理Working principle of open current transformer

開口低壓電流互感器的工作原理如圖1所示，開口電流互感器的一次繞組串聯在被測線路中，I1為線路電流即電流互感器的一次電流，N1為電流互感器的一次匝數，I2電流互感器二次電流（通常為5A、1A），N2為電流互感器的二次匝數，Z2e為二次回路設備及連接導線阻抗。當一次電流從電流互感器P1端流進，P2端出，在二次Z2e接通的情況下，由電磁感應原理，電流互感器二次繞組有電流I2從S1流過，經Z2e至S2，形成閉合回路。由此可得電流在理想狀態下I1×N1=I2×N2，所以有I1/I2=N1/N2=K，K為電流互感器的變比。但是由于開口式電流互感器的鐵芯切開后，使鐵芯的性能下將的比較厲害，所以須將互感器的鐵芯截面積加大，而且提高安匝數，將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.

圖2 Figure.2

注：圖2中1-開口電流互感器的上體，2-開口電流互感器的下體，3-安裝螺絲、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）產品安裝Product installation

如圖2所示，將互感器的安裝螺絲、螺母打開，卸下互感器的下體，將互感器的上體裝入配電系統的一次母排，合上互感器的下體，將互感器的安裝螺絲穿過互感器上、下體的固定孔，擰上螺母，將互感器的上、下體固定在一起，然后將互感器通過互感器兩側的安裝固定孔將互感器固定在母排上，完成互感器的安裝。然后將互感器的二次接到測量裝置。整個過程比較快速簡單。       

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.應用 Applications

開口電流互感器主要應用在低壓配電改造項目中，開口式電流互感器同常規閉口互感器一樣輸出為標準的5A或1A，測量精度高，容量大，可與測量儀器、儀表配套使用，部分產品過載能力強可與裝置配套使用。

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.

越南美的工廠為例如圖3所示，每條線均需測量三相電流,將采集的電流信號供給電能表DTSD1352，組網之后數據傳輸到美的工業云系統。A相、B相、C相的可以選擇我們的圓孔型開口互感器，每相額定電流為400A,采用AKH-0.66/K K-∮36 400/5開口電流互感器采集電流信號。現場無需拆線或者銅排。

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.

圖3 Figure.3

4.結束語Summary

開口式電流互感器已經成熟的在多個國家工礦企業工程配電監控系統中得到應用，降低了投資成本，提供工作效率及減輕工作難度。

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.

參考文獻 Bibliography

1.Solutions For Enterprise Micro-grid System 2020.02