In the selection of ABB miniature circuit breaker, low-voltage circuit breaker and leakage circuit breaker account for a large share, so it is very necessary to understand some selection principles. This paper will introduce the selection principles of these two circuit breakers in detail.

一、ABB微型断路器的选用

1、 Selection of ABB miniature circuit breaker

ABB微型断路器的选用，应根据具体使用条件选择使用类别，选择额定工作电压、额定电流、脱扣器整定电流和分励、欠压脱扣器的电压电流等参数，参照产品样本提供的保护特性曲线选用保护特性，并需对短路特性和灵敏系数进行校验。当与另外的断路器或其他保护电器之间有配合要求时，应选用选择型断路器。作为例子，用DZ20断路器作参考。

For the selection of ABB miniature circuit breaker, the use category shall be selected according to the specific use conditions, and the parameters such as rated working voltage, rated current, setting current of release, voltage and current of shunt and undervoltage release shall be selected. The protection characteristics shall be selected with reference to the protection characteristic curve provided by the product sample, and the short-circuit characteristics and sensitivity coefficient shall be verified. When there are coordination requirements with other circuit breakers or other protective appliances, selective circuit breakers shall be selected. As an example, DZ20 circuit breaker is used as a reference.

1.额定工作电压流和额定电压 低压断路器的额定工作电压Ue和额定电流Ie。应分别不低于线路，设备的正常额定工作电压和工作电流或计算电流。断路器的额定工作电压与通断能力及使用类别有关，同一台断路器产品可以有几个额定工作电压和相对应的通断能力及使用类别。

1. Rated working voltage current and rated voltage rated working voltage Ue and rated current ie of low-voltage circuit breaker. It shall not be lower than the normal rated working voltage and working current or calculated current of the line and equipment respectively. The rated working voltage of the circuit breaker is related to the making and breaking capacity and use category. The same circuit breaker product can have several rated working voltages and corresponding making and breaking capacity and use category.

2.长延时脱扣器整定电流Ir1 所选断路器的长延时脱扣器整定电流Ir1；应大于或等于线路的计算负载电流，可按计算负载电流的1-1.1倍确定；同时应不大于线路导体长期允许电流的0.8-1倍。

2. Setting current IR1 of long time delay release setting current IR1 of the selected circuit breaker; It shall be greater than or equal to the calculated load current of the line, which can be determined by 1-1.1 times of the calculated load current; At the same time, it shall not be greater than 0.8-1 times of the long-term allowable current of the line conductor.

3.瞬时或短延时脱扣器的整定电流Ir2 所选断路器的瞬时或短延时脱扣器整定电流Ir2应大于线路尖峰电流。配电断路器可按不低于尖峰电流1.35倍的原则确定，电动机保护电路当动作时间大于0.002s 时可按不低于1.35倍起动电流的原则确定，如果动作时间小于0.02s，则应增加为不低于起动电流的1.7-2倍。这些系数是考虑到整定误差和电动机起动电流可能变化等因素而加的。

3. The setting current IR2 of the instantaneous or short delay release of the selected circuit breaker shall be greater than the line peak current. The distribution circuit breaker can be determined according to the principle of not less than 1.35 times of peak current. When the action time of motor protection circuit is greater than 0.002s, it can be determined according to the principle of not less than 1.35 times of starting current. If the action time is less than 0.02s, it should be increased to not less than 1.7-2 times of starting current. These coefficients are added considering the setting error and the possible change of motor starting current.

4.短路通断能力和短时耐受能力校验 低压断路器的额定短路分断能力和额定短路接通能力应不低于其安装位置上的预期短路电流。当动作时间大于0.0.2s时，可不考虑短路电流的非周期分量，即把短路电流周期分量有效值作为短路电流；当动作时间小于0.02s时，应考虑非周期分量，即把短路电流周期内的全电流作为短路电流。如校验结果说明断路器通断能力不够，应采取如下措施。

4. Short circuit making and breaking capacity and short-time withstand capacity verification the rated short-circuit breaking capacity and rated short-circuit making capacity of low-voltage circuit breaker shall not be lower than the expected short-circuit current at its installation position. When the action time is greater than 0.0.2s, the aperiodic component of short-circuit current can be ignored, that is, the effective value of periodic component of short-circuit current can be taken as the maximum short-circuit current; When the action time is less than 0.02s, the aperiodic component shall be considered, that is, the full current in the first cycle of short-circuit current shall be taken as the maximum short-circuit current. If the verification results show that the on-off capacity of the circuit breaker is insufficient, the following measures shall be taken.

1）在断路器的电源侧增设其他保护电器（如熔断器〕作为后备保护。

1) Add other protective appliances (such as fuses) at the power side of the circuit breaker as backup protection.

2）采用限流型断路器，可按制造厂提供的允通电流特性或限流系数（即实际分断电流峰值和预期短路电流峰值之比）选择相应的产品。

2) The current limiting circuit breaker can be selected according to the allowable current characteristics or current limiting coefficient (i.e. the ratio of the actual breaking current peak to the expected short-circuit current peak) provided by the manufacturer.

3）时改选较大容量的断路器。各种短路保护断路器必须能在闭合位置上承载未受限制的短路电流瞬态值，还须能在规定的延时范围内承载短路电流。这种短时承载的短路电流值应不超过断路器的额定短时耐受能力，否则也应采取措施或改变断路器规格。断路器产品样本中一般都给出产品的额定峰值耐受电流和额定短时耐受电流（Is电流）。当为交流电流时，短时耐受电流应以未受限制的短路电流周期分量的有效值为准。

3) The circuit breaker with larger capacity shall be selected when. Various short-circuit protection circuit breakers must be able to carry unrestricted short-circuit current transient value in the closed position and short-circuit current within the specified time delay range. The short-circuit current value of this short-time load shall not exceed the rated short-time withstand capacity of the circuit breaker, otherwise measures shall be taken or the specification of the circuit breaker shall be changed. The rated peak withstand current and rated short-time withstand current (is current) of the product are generally given in the product sample of circuit breaker. In case of AC current, the short-time withstand current shall be subject to the effective value of unrestricted short-circuit current periodic component.

二、漏电断路器的选用

2、 Selection of leakage circuit breaker

漏电断路器具有两个功能，一是具有断路器的功能，二是具有漏电保护的功能。断路器功能与一般低压断路器相同，漏电保护部分通过零序互感器检测的是剩余电流，即通过检测被保护回路内相线和中性线的电流瞬时值，判断对地泄漏电流的变化。因此，断路器，如常见的DZ47LE漏电断路器功能部分的选择与一般低压断路器相同。漏电保护功能部分（下称漏电保护器）的选择应考虑两个基本条件，一是漏电保护器的漏电动作电流必须躲过电网正常泄漏电流，二是漏电保护器的漏电动作电流必须小于引起火灾的小点燃电流或人体电流，按选用漏电保护器的主要目的确定。一般按以下原则选择。

The leakage circuit breaker has two functions: one is the function of circuit breaker, and the other is the function of leakage protection. The function of the circuit breaker is the same as that of the general low-voltage circuit breaker. The leakage protection part detects the residual current through the zero sequence transformer, that is, judge the change of the leakage current to the ground by detecting the instantaneous current value of the phase line and neutral line in the protected circuit. Therefore, the selection of the functional part of the circuit breaker, such as the common dz47le leakage circuit breaker, is the same as that of the general low-voltage circuit breaker. The selection of leakage protection function part (hereinafter referred to as leakage protector) shall consider two basic conditions: one is that the leakage action current of leakage protector must avoid the normal leakage current of power grid; the other is that the leakage action current of leakage protector must be less than the minimum ignition current or human safety current causing fire, which shall be determined according to the main purpose of selecting leakage protector. Generally, it is selected according to the following principles.

（1）选择漏电保护器的额定动作电流按标准GB13955-92《漏电保护器安装和运行》的规定，选择漏电保护器的额定动作电流应根据电气线路的正常泄漏电流确定，并应充分考虑到被保护线路和设备可能发生的正常泄漏电流值，必要时可通过实际测量取得被保护线路和设备的泄漏电流值。

(1) The rated operating current of the leakage protector shall be selected according to the provisions of the national standard gb13955-92 installation and operation of leakage protector. The rated operating current of the leakage protector shall be determined according to the normal leakage current of the electrical line, and the possible normal leakage current of the protected line and equipment shall be fully considered, If necessary, the leakage current value of the protected line and equipment can be obtained through actual measurement.

（2）选择漏电保护器的额定漏电不动作电流按标准《漏电保护器安装和运行》的规定，漏电保护器的额定漏电不动作电流应不小于电气线路和设备的正常泄漏电流的值的2倍。

(2) Select the rated leakage non action current of the leakage protector. According to the provisions of the national standard installation and operation of leakage protector, the rated leakage non action current of the leakage protector shall not be less than twice the maximum value of the normal leakage current of electrical lines and equipment.

（3）电气线路和设备泄漏电流值与分级安装的漏电保护特性的配合

(3) Coordination between leakage current value of electrical lines and equipment and leakage protection characteristics of graded installation

1）用于单台用电设备时，漏电保护器动作电流应不小于正常运行实测泄漏电流的4倍。以防止因漏电引起触电事故和火灾。

1) When used for single electrical equipment, the action current of leakage protector shall not be less than 4 times of the measured leakage current in normal operation. To prevent electric shock and fire caused by electric leakage.

2）配电线路的漏电保护器动作电流应不小于正常运行实测泄漏电流的2.5 倍，同时还应满足其中泄漏电流的一台用电设备正常运行泄漏电流的4 倍。以防止因漏电引起火灾。

2) The action current of the leakage protector of the distribution line shall not be less than 2.5 times of the measured leakage current in normal operation, and shall also meet 4 times of the normal operation leakage current of the electric equipment with the largest leakage current. To prevent fire caused by electric leakage.

3）用于全网保护时，动作电流应不小于实测泄漏电流的2倍。为全网增设的漏电保护，防止因漏电引起火灾。

3) When used for the whole network protection, the action current shall not be less than 2 times of the measured leakage current. Add comprehensive leakage protection for the whole network to prevent fire caused by leakage.

（4）一般地，不同额定剩余动作电流的漏电保护器可按以下原则选用。如常用型号：DZ47LE-32

(4) Generally, leakage protectors with different rated residual operating current can be selected according to the following principles. For example, common model: DZ47LE-32

1）额定剩余动作电流为30mA及以下的漏电保护器，用于对直接接触及TT系统的保护；及不直接接触、IT中性线不接地系统和完全暴露条件（如建筑工地、游泳池、娱乐场所等）的保护。

1) Leakage protector with rated residual operating current of 30mA and below is used to protect direct contact and TT system; And the protection of non direct contact, it neutral ungrounded system and completely exposed conditions (such as construction sites, swimming pools, entertainment places, etc.).

2）额定剩余动作电流为50mA及以上的漏电保护器，用于对非直接接触及TT系统及防止火灾的保护。

2) Leakage protector with rated residual operating current of 50mA and above is used to protect indirect contact and TT system and prevent fire.

3）配置选择性保护时应保证除对非直接接触及TT系统可保护外，还能对下级装有30mA的漏电保护系统作选择性保护。仅隔离事故电路，其它电路仍应保证继续供电。

3) When configuring selective protection, it shall be ensured that in addition to the protection of indirect contact and TT system, it can also provide selective protection for the lower level leakage protection system equipped with 30mA. Only isolate the accident circuit, and other circuits shall still ensure continuous power supply.

以上就是关于ABB微型断路器和漏电断路器选型中需要注意的原则，相信对大家能有所帮助！

The above is about the principles that should be paid attention to in the selection of ABB miniature circuit breaker and leakage circuit breaker. I believe it can be helpful to you!