由具有相似特性的负荷组的局部功率因数校正组成
通过安装专用电容器组实现功能特性。
该方法在经济解决方案和
安装的正确操作，因为只有
电容器组的安装点未正确利用。
集中式PFC
日负荷曲线对于选择大负荷具有根本重要性
合适类型的功率因数校正。
在安装中，并非所有负载同时工作和/或
一些负荷每天只连接几个小时，解决方案是使用
单个PFC变得不合适，因为安装的许多电容器可能会保留下来
长时间闲置。
如果装置偶尔有许多负载运行，因此
具有较高的安装功率和相当低的平均功率吸收
同时工作的负载，在
安装原点确保了总功率的显著降低
安装电容器。
功率因数负载组
已更正
ABB |电气设备435
3功率因数校正
3.2功率因数连接方法
集中式功率因数校正通常使用自动单元，其中电容器组分为
几个步骤，直接安装在主配电盘中；使用
只有在吸收
中，无功能量的消耗是相当有规律的。
集中式PFC的主要缺点是
PFC装置下游的安装尺寸必须考虑
计算负荷所需的全部无功功率。
3.3保护断路器和
电容器组的切换
低压电容器组保护和切换用断路器
应：
1、承受连接和连接时产生的瞬态电流
断开银行的连接。特别是瞬时磁场和
电子脱扣器不得因这些峰值电流而跳闸；
2、承受由电压引起的周期性或性过电流
谐波和容量额定值的公差（+15%）；
3、执行大量空载和有载操作，也包括高负载
频率
4、与任何外部设备（接触器）协调。
此外，断路器的接通和断开容量必须为
足以满足装置的短路电流值。
IEC 60831-1和60931-1标准规定：
-电容器的有效电流值通常应高达130%
其额定电流Irc（由于可能存在电压谐波）
网络）；
-对于高达100 kvar的组，电容的容差为10%，容差为5%
对于超过100 kvar的组，允许使用。
电容器组Icmax可吸收的大电流为：
因此：
-断路器的额定电流应大于1.5⋅我
rc；
-过载保护设置应等于1.5⋅我
钢筋混凝土。
电容器组的连接，类似于短路条件下的闭合操作，与高频（1÷15）瞬态电流相关
kHz），持续时间短（1÷3 ms），峰值高（25÷200 Irc）。
因此：
-断路器应具有足够的闭合能力；
-瞬时短路保护的设置不得导致意外跳闸。

consists of local power factor correction of groups of loads with similar functioning characteristics by installing a dedicated capacitor bank. This method achieves a compromise between the economical solution and the correct operation of the installation, since only the line downstream of the installation point of the capacitor bank is not correctly exploited. Centralized PFC The daily load profile is of fundamental importance for the choice of the most suitable type of power factor correction. In installations, in which not all loads function simultaneously and/or in which some loads are connected for only a few hours a day, the solution of using single PFC becomes unsuitable as many of the capacitors installed could stay idle for long periods. In the case of installations with many loads occasionally functioning, thus having a high installed power and a quite low average power absorption by the loads which function simultaneously, the use of a single PFC system at the installation origin ensures a remarkable decrease in the total power of the capacitors to be installed. Group of loads to be power factor corrected ABB | Electrical devices 435 3 Power factor correction 3.2 Power factor connection method Centralized PFC normally uses automatic units with capacitor banks divided into several steps, directly installed in the main distribution switchboards; the use of a permanently connected capacitor bank is only possible if the absorption of reactive energy is fairly regular throughout the day. The main disadvantage of centralized PFC is that the distribution lines of the installation, downstream of the PFC device, must be dimensioned taking into account the full reactive power required by the loads. 3.3 Circuit-breakers for the protection and switching of capacitor banks The circuit-breakers for the protection and switching of capacitor banks in LV shall: 1. withstand the transient currents which occur when connecting and disconnecting the banks. In particular, the instantaneous magnetic and electronic releases shall not trip due to these peak currents; 2. withstand the periodic or permanent overcurrents due to the voltage harmonics and to the tolerance (+15%) of the rated value of capacity; 3. perform a high number of no-load and on-load operations, also with high frequency; 4. be coordinated with any external device (contactors). Furthermore, the making and breaking capacity of the circuit-breaker must be adequate to the short- circuit current values of the installation. Standards IEC 60831-1 and 60931-1 state that: - the capacitors shall normally function with an effective current value up to 130% of their rated current Irc (due to the possible presence of voltage harmonics in the network); - a tolerance of 10% on the capacitance for banks up to 100 kvar and of 5% for banks exceeding 100 kvar is admited. The maximum current which can be absorbed by the capacitor bank Icmax is: Therefore: - the rated current of the circuit-breaker shall be greater than 1.5⋅I rc; - the overload protection setting shall be equal to 1.5⋅I rc. The connection of a capacitor bank, similar to a closing operation under shortcircuit conditions, associated with transient currents with high frequency (1÷15 kHz), of short duration (1÷3 ms), with high peak (25÷200 Irc). Therefore: - the circuit-breaker shall have an adequate making capacity; - the setting of the instantaneous short-circuit protection must not cause unwanted trips.