CN201797318U - Reactance Adjustable Reactive Power Compensator - Google Patents

Reactance Adjustable Reactive Power Compensator Download PDF

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CN201797318U
CN201797318U CN2010201185093U CN201020118509U CN201797318U CN 201797318 U CN201797318 U CN 201797318U CN 2010201185093 U CN2010201185093 U CN 2010201185093U CN 201020118509 U CN201020118509 U CN 201020118509U CN 201797318 U CN201797318 U CN 201797318U
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reactance
reactive power
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薛兴华
张金波
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30Reactive power compensation
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40Arrangements for reducing harmonics

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Abstract

A reactance-adjustable reactive power compensator comprises an adjustable reactor and a capacitor bank. The adjustable reactor and the capacitor bank are parallelly connected onto a circuit after being serially connected with each other, the adjusting reactor adopts a magnetic valve dry-type iron core reactor, and is mainly used for restraining power harmonics and limiting switching-on inrush current when in high and low voltage power grid reactive power compensation, and the reactor leads reactance rate to meet certain requirements so as to achieve the best harmonic restraining effect by means of adjusting inductive reactance value of the reactor according to conditions of power harmonics, so that functions of not only compensating power grid reactive power but avoiding changing effect of restraining certain harmonic.

Description

电抗可调式无功功率补偿器 Reactance adjustable reactive power compensator

技术领域technical field

本实用新型涉及一种用于高低压电网无功功率动态补偿时抑制电网谐波和限制合闸涌流的电抗可调式无功功率补偿器。 The utility model relates to an adjustable reactance reactive power compensator for suppressing grid harmonics and limiting closing inrush current during dynamic compensation of reactive power of high and low voltage grids. the

背景技术Background technique

目前国内外在无功功率补偿和谐波治理方面都已经积累了比较丰富的经验,并且国内外均有比较成熟的产品,无功功率补偿通常采用投切电容器的方法,谐波治理通常采用无源或有源滤波器来实现谐波的治理,无源滤波器主要是由电抗器和电容器串联构成,具有容易设计的优点,但是其滤波效果依赖于系统阻抗特性。尽管有源电力滤波器有着无源滤波器所不具备的巨大技术优势,但目前要想在电力系统中完全取代无源滤波器还不现实,这是因为与无源滤波器相比较,有源电力滤波器的成本高,这一点是限制有源电力滤波器推广使用的主要原因,因此,无源滤波器目前使用还比较普遍。 At present, both at home and abroad have accumulated relatively rich experience in reactive power compensation and harmonic control, and there are relatively mature products at home and abroad. Reactive power compensation usually adopts the method of switching capacitors, and harmonic control usually uses wireless Harmonic control is achieved by using a source or an active filter. The passive filter is mainly composed of a reactor and a capacitor in series, which has the advantage of being easy to design, but its filtering effect depends on the impedance characteristics of the system. Although active power filters have great technical advantages that passive filters do not have, it is not realistic to completely replace passive filters in power systems at present, because compared with passive filters, active The high cost of power filters is the main reason for limiting the popularization and use of active power filters. Therefore, passive filters are still widely used at present. the

由于电网负载情况复杂,绝大多数电网都需要同时进行无功功率补偿和谐波治理,这样就需要两套装置,况且直接将电容器并联在电网上进行无功补偿,电网上将会产生一定的谐波放大,在并联电容器的回路中串联电抗器是非常有效和可行的方法解决谐波放大问题,若电抗器的电抗率选择合适又可以抑制高次谐波的作用。因此,目前国内电网无功补偿装置都是将固定的电抗器串联于电容器回路中,这样不仅能对电网中无功功率进行补偿,还可以抑制电网中的谐波。而实际电网中负载是在不断变化的,功率因数也随时在变化,为了适应电网变化的功率因数,就要求采用多组电容器分组投切,以达到对电网功率因数进行动态补偿的目的。如果电容器的组数发生变化,而电抗器的感抗值不变,则起不到抑制谐波的作用,还有可能出现谐波放大的效果。为了达到既起到功率补偿又抑制电网谐波通常采用多组电抗器分别与多组电容器串联组合使用,这种方法缺点是需要多组电抗器,增加了设备投资,也增加了占地面积。 Due to the complex load conditions of the power grid, most power grids need to perform reactive power compensation and harmonic control at the same time, so two sets of devices are required. Moreover, directly connecting capacitors in parallel to the power grid for reactive power compensation will generate a certain amount of noise on the power grid. Harmonic amplification, series reactors in the circuit of parallel capacitors is a very effective and feasible method to solve the problem of harmonic amplification. If the reactance rate of the reactor is selected properly, the effect of higher harmonics can be suppressed. Therefore, the current reactive power compensation devices in the domestic power grid connect fixed reactors in series with the capacitor circuit, which can not only compensate the reactive power in the power grid, but also suppress the harmonics in the power grid. In the actual power grid, the load is constantly changing, and the power factor is also changing at any time. In order to adapt to the changing power factor of the power grid, it is required to use multiple groups of capacitors to switch in groups to achieve the purpose of dynamically compensating the power factor of the power grid. If the number of capacitor groups changes, but the inductance value of the reactor remains unchanged, the effect of harmonic suppression will not be achieved, and the effect of harmonic amplification may also occur. In order to achieve both power compensation and grid harmonic suppression, multiple sets of reactors are usually used in series with multiple sets of capacitors. The disadvantage of this method is that multiple sets of reactors are required, which increases equipment investment and floor space. the

通过上述分析及电网的实际运行情况,电抗可调式无功功率补偿器可以实现无功功率补偿和谐波治理于一体的补偿滤波效果,这样不仅可以减少设备投资,减少了设备的占地面积,同时也实现了无功功率补偿与谐波治理的双重效果,因此,电抗率可调的干式铁芯电抗器具有非常重要的实际应用价值。 Through the above analysis and the actual operation of the power grid, the reactance adjustable reactive power compensator can realize the compensation and filtering effect of reactive power compensation and harmonic control, which can not only reduce equipment investment, but also reduce the equipment footprint. At the same time, the dual effects of reactive power compensation and harmonic control are realized. Therefore, the dry-type iron core reactor with adjustable reactance rate has very important practical application value. the

实用新型内容Utility model content

本实用新型所要解决的技术问题是串联电抗器的感抗值,即电抗率在一定范围内连续可调,以达到当电网谐波和无功功率变化时自动进行调节,使无功功率补偿和谐波抑制达到最佳效果,并且可以减少设备投资和减小设备占地面积。 The technical problem to be solved by the utility model is the inductive reactance value of the series reactor, that is, the reactance rate can be continuously adjusted within a certain range, so as to automatically adjust when the grid harmonics and reactive power change, so that the reactive power compensation and Harmonic suppression achieves the best effect, and can reduce equipment investment and equipment footprint. the

为解决上述技术问题,本实用新型提供了一种用于高低压电网无功补偿时抑制谐波和限制涌流的电抗可调式无功功率补偿器。 In order to solve the above technical problems, the utility model provides an adjustable reactance reactive power compensator for suppressing harmonics and limiting inrush current during reactive power compensation of high and low voltage power grids. the

电抗可调式无功功率补偿器包括可调电抗器和电容器组;可调电抗器和电容器组串联后并联在线路上。 The adjustable reactance reactive power compensator includes an adjustable reactor and a capacitor bank; the adjustable reactor and capacitor bank are connected in series and connected in parallel on the line. the

电抗可调式无功功率补偿器的电容器组包括多组开关和多组电容器;每一个开关和每一个电容器串联后再相互并联,构成电容器组。 The capacitor bank of the reactance adjustable reactive power compensator includes multiple sets of switches and multiple sets of capacitors; each switch and each capacitor are connected in series and then connected in parallel to form a capacitor bank. the

电抗可调式无功功率补偿器的可调电抗器包括电抗器线圈和电抗器铁芯构成,电抗器铁芯采用变截面,在铁芯中间把铁芯的截面减小一小段,通过改变小截面磁路的饱和程度来改变电抗器的感抗值。 The adjustable reactor of the adjustable reactance reactive power compensator consists of a reactor coil and a reactor core. The saturation degree of the magnetic circuit changes the inductive reactance value of the reactor. the

电抗可调式无功功率补偿器的开关可以是交流接触器、可控硅或复合开关;若开关是交流接触器,则在交流接触器回路中串接一个熔断器,以保护开关。 The switch of the reactance adjustable reactive power compensator can be an AC contactor, a thyristor or a composite switch; if the switch is an AC contactor, a fuse is connected in series in the AC contactor circuit to protect the switch. the

本实用新型具有积极的效果:(1)电抗器的感抗值通过调节电抗器铁芯的磁路饱和程度实现连续调节,使电抗率在0.1~1%、4.5%~6%和6%~12%或其他范围连续可调,可以满足当电网谐波波变化时对电网谐波最佳抑制的效果。(2)本实用新型的电抗可调式无功功率补偿器可以与电容器组任意组合,保持电抗率不变,实现对电网无功功率补偿的同时,抑制谐波的功能也保持不变。(3)本实用新型的电抗可调式无功功率补偿器的电抗器线圈和铁芯采用环氧浇制,可以是干式自然冷却,也可以采用油浸式冷却,安装方便。The utility model has positive effects: (1) The inductive reactance value of the reactor is continuously adjusted by adjusting the saturation degree of the magnetic circuit of the reactor iron core, so that the reactance rate is 0.1-1%, 4.5%-6% and 6%- 12% or other ranges are continuously adjustable, which can meet the best suppression effect on grid harmonics when grid harmonics change. (2) The reactance-adjustable reactive power compensator of the utility model can be combined with the capacitor bank arbitrarily to keep the reactance rate unchanged, realize the reactive power compensation of the grid, and keep the function of suppressing harmonics unchanged. (3) The reactor coil and iron core of the reactance-adjustable reactive power compensator of the utility model are made of epoxy casting, which can be either dry-type natural cooling or oil-immersed cooling, and is easy to install.

附图说明Description of drawings

图1为实施例1的可调电抗器与电容器组的连接图 Fig. 1 is the connection diagram of the adjustable reactor and capacitor bank of embodiment 1

图2为实施例1的电容器组组成原理图 Fig. 2 is the composition schematic diagram of the capacitor bank of embodiment 1

图3为实施例1的可调电抗器的原理图 Fig. 3 is the schematic diagram of the adjustable reactor of embodiment 1

图4为实施例1的并联电容器装置接至母线示意图和单相等值回路 Fig. 4 is the schematic diagram of the shunt capacitor device connected to the bus bar and the single-phase value circuit of embodiment 1

图5为实施例1的串并联谐振原理图 Fig. 5 is the series-parallel resonance schematic diagram of embodiment 1

具体实施方式Detailed ways

见图1和图2,本实施例的电抗可调式无功功率补偿器,包括可调电抗器1和电容器组2;可调电抗器1和电容器组2串联后并联在线路上;电容器组2包括多组开关2-1和多组电容器2-2;每一个开关2-1和每一个电容器2-2串联后再相互并联,构成电容器组。本实施例的可调电抗器1由电抗器线圈1-1和电抗器铁芯1-2组成,电抗器铁芯1-2采用变截面,在铁芯中间把铁芯的截面减小一小段,通过改变小截面磁路的饱和程度来改变电抗器的感抗值,如图3所示为磁阀式可调电抗器的结构和电路图。电抗器的主铁芯分裂为两半,截面积各为Ay,长度为l~lt。不同的是每一半铁芯具有一长度为lt的小截面段,其面积为Ayt(Ayt<Ay)。四个匝数为N/2的绕组分别对称地绕在两个半铁芯柱上。每一半铁芯柱上的上下两绕组各有一抽头比为δ=N2/N的抽头,它们之间接有晶闸管KP1、KP2。不同铁芯的上下两个绕组交叉连接后,并联到电网,续流二极管则横跨在交叉端点上。由图2可知,若KP1、KP2不导通,根据绕组结构的对称性可知,此时电抗器与空载变压器没有差别。当电源处于正半周时,晶闸管KP1承受正向电压,KP2承受反向电压。若KP1被触发导通(即a、b两点等电位),电源经电压比为δ的绕组自耦变压后由匝数为N2的绕组向电路提供直流控制电压和电流。同理,若KP2在电源负半周时触发导通,也将产生直流控制电压和电流,而且,控制电流的方向与KP1导通时一致。在电源的一个工频周期内,可控硅KP1、KP2的轮流导通起了全波整流的作用,二极管起着续流作用。改变KP1、KP2的触发角便可改变控制电流的大小,从而改变电抗器铁芯的饱和度,平滑连续地调节电抗器的容量。由图1可知,磁阀式可调电抗器铁芯磁路由面积较大的部分(面积为Ay,长度为l-lt)和面积较小的部分(面积为Ayt,长度为lt)串联而成。由于在磁阀式可调电抗器的整个容量调节范围内,大面积段铁芯的工作状态始终处于磁路的未饱和线性区,其磁阻相对小面积lt段铁芯很小,故予忽略。可见,磁阀式可调电抗器的磁路是“阀式”结构,当面积为Ayt的小截面铁芯完全饱和时,相当于磁阀门全部关闭,磁阻最大,此时整个磁路犹如面积为Ay、长度为lt的空气隙(要注意,此时面积为Ay的铁心段不饱和)。而当面积为Ayt的小截面铁芯段处于未饱和线性区时,磁阻十分小,磁力线几乎完全从中通过,磁阀门完全打开。在其他情况下,磁力线将有一部分通过面积为Ay-Ayt的空气隙,另一部分通过小截面铁芯段,前者的磁阻为线性,后者的磁阻为非线性,所以,电抗器的磁路由两个并联的磁阻组成。 See Fig. 1 and Fig. 2, the reactance adjustable reactive power compensator of the present embodiment, comprises adjustable reactor 1 and capacitor bank 2; Adjustable reactor 1 and capacitor bank 2 are connected in parallel on the line after being connected in series; Capacitor bank 2 comprises Multiple sets of switches 2-1 and multiple sets of capacitors 2-2; each switch 2-1 and each capacitor 2-2 are connected in series and then connected in parallel to form a capacitor bank. The adjustable reactor 1 of this embodiment is composed of a reactor coil 1-1 and a reactor core 1-2. The reactor core 1-2 adopts a variable section, and the section of the iron core is reduced by a small section in the middle of the iron core. , by changing the saturation degree of the small cross-section magnetic circuit to change the inductance value of the reactor, as shown in Figure 3 is the structure and circuit diagram of the magnetic valve adjustable reactor. The main iron core of the reactor is split into two halves, each with a cross-sectional area of A y and a length of l~l t . The difference is that each half of the iron core has a small section with a length of l t and an area of A yt (A yt <A y ). The four windings with the number of turns of N/2 are symmetrically wound on the two half-core legs respectively. The upper and lower windings on each half of the iron core have a tap with a tap ratio of δ=N 2 /N, and thyristors K P1 and K P2 are connected between them. After the upper and lower windings of different iron cores are cross-connected, they are connected to the power grid in parallel, and the freewheeling diodes are straddled on the cross terminals. It can be seen from Figure 2 that if K P1 and K P2 are not conducting, according to the symmetry of the winding structure, there is no difference between the reactor and the no-load transformer at this time. When the power supply is in the positive half cycle, the thyristor K P1 bears the forward voltage, and K P2 bears the reverse voltage. If K P1 is triggered to be turned on (that is, two points a and b are at the same potential), the power supply will provide DC control voltage and current to the circuit through the winding with N2 turns after autotransformation by the winding with a voltage ratio of δ. Similarly, if K P2 is triggered to be turned on during the negative half cycle of the power supply, a DC control voltage and current will also be generated, and the direction of the control current is the same as that when K P1 is turned on. In a power frequency cycle of the power supply, the turn-on of the thyristors K P1 and K P2 plays the role of full-wave rectification, and the diode plays the role of freewheeling. Changing the firing angles of K P1 and K P2 can change the size of the control current, thereby changing the saturation of the reactor iron core, and adjusting the capacity of the reactor smoothly and continuously. It can be seen from Fig. 1 that the iron core magnetic path of the magnetic valve type adjustable reactor has a larger area (area A y , length ll t ) and a smaller area (area A yt , length l t ) in series made. Because in the entire capacity adjustment range of the magnetic valve type adjustable reactor, the working state of the large-area section iron core is always in the unsaturated linear region of the magnetic circuit, and its reluctance is relatively small compared to the small-area l t- section iron core, so it is ignored. It can be seen that the magnetic circuit of the magnetic valve-type adjustable reactor is a "valve-type" structure. When the small-section iron core with an area of A yt is completely saturated, it is equivalent to all the magnetic valves being closed, and the magnetic resistance is the largest. At this time, the entire magnetic circuit is like An air gap with area A y and length l t (it should be noted that the core segment with area A y is not saturated at this time). And when the small cross-section iron core segment with area A yt is in the unsaturated linear region, the reluctance is very small, the magnetic force lines almost completely pass through it, and the magnetic valve is fully opened. In other cases, part of the magnetic flux will pass through the air gap with an area of A y -A yt , and the other part will pass through the small-section iron core segment. The reluctance of the former is linear, and the reluctance of the latter is nonlinear. Therefore, the reactor The magnetic circuit consists of two parallel reluctances.

串联电抗器单相容量的选择:如图4所示,装置接至母线,其电容器组和电抗器串联,一般三相采用中性点不接地星形连接,每相的容量相等,故可用图4单相等值回路表示。装置的额定电抗率可下式计算,即:K=XL/XC,其中UC=ICXC,UL=ICXL,QL=ULIL=IL 2XL=KIC 2XC=KQC Selection of single-phase capacity of series reactor: as shown in Figure 4, the device is connected to the busbar, and its capacitor bank is connected in series with the reactor. Generally, the three-phase is connected in a star-shaped neutral point without grounding, and the capacity of each phase is equal. 4 single-phase value loop representation. The rated reactance rate of the device can be calculated by the following formula, namely: K=X L /X C , where U C =I C X C , U L =IC X L , Q L =U L I L =I L 2 X L =KI C 2 X C =KQ C

由此可得,串联电抗器单相容量等于电容器组单相容量乘以装置的额 定电抗率K。 It can be obtained that the single-phase capacity of the series reactor is equal to the single-phase capacity of the capacitor bank multiplied by the rated reactance rate K of the device. the

串联电抗器电抗率K的选择:并联谐波谐振:在电力系统中,安装并联电容器组是为了补偿无功功率,提高电压水平。但加装并联电容器组会改变系统谐波阻抗的频率特性,对于工频,系统的感抗XS很小,因而一般不会发生谐振,但当系统中含有谐波分量时,就可能发生与系统的并联谐振。如图5所示,n为谐波次数;In为电网中谐波电流源;Un为谐波电流注入点母线谐波电压;nXs为系统等值谐波感抗;XC/n为电容器组谐波抗容;nXL为电容器组串联电抗器谐波感抗。 Selection of reactance rate K of series reactor: Parallel harmonic resonance: In power system, parallel capacitor bank is installed to compensate reactive power and increase voltage level. However, adding a parallel capacitor bank will change the frequency characteristics of the harmonic impedance of the system. For power frequency, the inductive reactance X S of the system is very small, so resonance generally does not occur, but when the system contains harmonic components, it may occur with Parallel resonance of the system. As shown in Figure 5, n is the harmonic order; I n is the harmonic current source in the grid; U n is the harmonic current injection point bus harmonic voltage; nX s is the system equivalent harmonic inductance; X C /n is the harmonic reactance of the capacitor bank; nX L is the harmonic inductive reactance of the series reactor of the capacitor bank.

并联谐振是系统与并联电容器组产生的谐振,其谐振频率取决于系统谐波感抗和电容器组谐波容抗(电容器支路),谐振条件为:系统谐波感抗=并联电容器谐波容抗-串联电抗器谐波感抗,即nXS=XC/n-nXL由XS=ωLS、XL=ωLL、XC=1/(ωC)可得nωLS=1/(nωC)-nωLL即谐振角频率ω=1/n(LS+LL)C而ω=2∏f,故谐振频率:f=1/2∏n(LS+LL)C。当n次谐波的频率接近谐振频率f时,就会发生并联谐振,这时回路中的电压和电流同相位,其等值谐波感抗Xn=nXS(nXL-XC/n)/nXS+nXL-XC/n,因发生并联谐波谐振时nXS+nXL≈XC/n,分母nXS+nXL-XC/n≈0,故Xn值很大,而Un=InXn,因此变电所母线上的谐振电压Un会很高。进入电容器组支路的谐波电流分配Icn=InnXs/(nXS+nXL-XC/n);进入系统的谐波电流分量Isn=In(nXL-XC/n)/(nXS+nXL-XC/n)。进入系统和电容器组支路的谐波电流分配因谐波次数、系统电抗和串联电抗器电抗率的不同而不同,有可能出现Isn>In,此时称为系统谐波电流放大;也可能出现Icn>In,此时称为电容器组谐波电流放大;当同时出现Isn>In、Icn>In时,称为谐波电流严重放大。发生并联谐振时,谐波电流放大达到最大值。 Parallel resonance is the resonance generated by the system and the parallel capacitor bank. Its resonant frequency depends on the system harmonic inductance and capacitor bank harmonic capacitance (capacitor branch). The resonance condition is: system harmonic inductance = parallel capacitor harmonic capacitance Anti-series reactor harmonic inductance, namely nX S =X C /n-nX L From X S =ωL S 、X L =ωL L 、X C =1/(ωC) nωL S =1/( nωC)-nωL L is the resonant angular frequency ω=1/n(L S +L L )C and ω=2∏f, so the resonant frequency: f=1/2∏n(L S +L L )C. When the frequency of the nth harmonic is close to the resonant frequency f, parallel resonance will occur. At this time, the voltage and current in the circuit are in phase, and its equivalent harmonic inductance X n = nX S (nX L -X C /n )/nX S +nX L -X C /n, because nX S +nX L ≈X C /n when parallel harmonic resonance occurs, the denominator nX S +nX L -X C /n≈0, so the value of X n is very is large, and U n =I n X n , so the resonant voltage U n on the substation bus will be very high. The harmonic current distribution I cn =I nn Xs/(nX S +nX L -X C /n) entering the capacitor bank branch; the harmonic current component entering the system I sn =I n (nX L -X C /n )/(nX S +nX L -X C /n). The distribution of harmonic current entering the system and capacitor bank branch is different due to the difference of harmonic order, system reactance and series reactor reactance, and I sn > I n may appear, which is called system harmonic current amplification; also I cn > In may occur, which is called capacitor bank harmonic current amplification; when I sn >I n and I cn > In appear at the same time, it is called severe harmonic current amplification. When parallel resonance occurs, the harmonic current amplification reaches its maximum value.

如前所述,发生并联谐波谐振的条件是nXs+nXL=XC/n,即nXS+nKXC=XC/n,K=1/n2-Xs/Xc。并联电容器组加装串联电抗器作为抑制谐波电流放大的有效措施,电容器组装置的额定电抗率应K>1/n2-Xs/Xc。设并联电容器组装置安装处的母线短路容量为Sd,则Sd=U2/Xs,又电容器组的容量QC=(3U2/XC)-2,故由K>1/n2-XS/XC可以推导出K>1/n2-QC/Sd,Qc>Sd(1/n2-K)这就是并联电容器装置设计规范所给出的校验避开并联谐振的电容器组容量,设计在确定电容器组分组容量时,应根据系统背景谐波,对分组电容器按各种容量组合运行时,尽量避开谐振容量进行校验,不得发生谐波的严重放大和谐振。 As mentioned above, the condition for parallel harmonic resonance to occur is nX s +nX L =X C /n, that is, nX S +nKX C =X C /n, K=1/n 2 -X s /X c . Adding series reactors to parallel capacitor banks is an effective measure to suppress harmonic current amplification, and the rated reactance rate of capacitor bank devices should be K>1/n 2 -X s /X c . Assume that the short-circuit capacity of the bus bar at the installation place of the parallel capacitor bank device is S d , then S d = U 2 /Xs, and the capacity of the capacitor bank Q C = (3U 2 /X C ) -2 , so K>1/n 2 -X S /X C can be deduced that K>1/n 2 -Q C /S d , Q c >S d (1/n 2 -K) This is the verification avoidance given by the design specification for parallel capacitor devices The capacitor bank capacity of parallel resonance should be designed according to the background harmonics of the system when determining the group capacity of the capacitor group. When the group capacitors are operated according to various capacity combinations, the resonance capacity should be avoided as far as possible for verification, and serious amplification of harmonics should not occur. Harmony.

串联谐波谐振:由串联电抗器和并联电容器组构成的串联回路对于n次谐波发生串联谐振的条件是:nXL=Xc/n,这时串联电抗器和并联电容器组构成的串联回路的总电抗为零,电流和电压同相位,回路电流达到最大值。要避免发生串联谐振,则应满足nXL>XC/n,即nKXC>XC/n,K>1/n2,即必须满足K>1/n2。由上述分析可知,避开并联谐振的电容器组装置额定电抗率K必须满足K>1/n2-QC/Sd。由于电容器组容量相对于系统短路容量很小即QC/Sd比值很小,显然避开发生串联谐振的电容器组装置额定电抗率K的取值与避开并联谐振K的取值非常接近。因此为避免运行中因各种原因滑入并联谐振状态,在实际工程中电容器组装置额定电抗率K按满足K>1/n2取值时,须留有一定裕度。 Series harmonic resonance: The series loop composed of series reactors and parallel capacitor banks has a condition for series resonance of the nth harmonic: nX L = X c /n, at this time, the series loop composed of series reactors and parallel capacitor banks The total reactance is zero, the current and voltage are in phase, and the loop current reaches the maximum value. To avoid series resonance, it should satisfy nX L >X C /n, that is, nKX C >X C /n, K>1/n 2 , that is, K>1/n 2 must be satisfied. It can be seen from the above analysis that the rated reactance K of the capacitor bank device that avoids parallel resonance must satisfy K>1/n 2 -Q C /S d . Since the capacity of the capacitor bank is very small relative to the short-circuit capacity of the system, that is, the ratio of Q C /S d is very small, it is obvious that the value of the rated reactance rate K of the capacitor bank device that avoids series resonance is very close to the value of K that avoids parallel resonance. Therefore, in order to avoid slipping into the parallel resonance state due to various reasons during operation, a certain margin must be left when the rated reactance rate K of the capacitor bank device satisfies K>1/n 2 in actual engineering.

达到的效果:可以根据电网谐波情况调节电抗率达到最佳抑制谐波的效果,还可以根据电网无功功率分组分别投切电容器时自动通过调整电抗器的感抗值保持电抗率K=XL/XC不变,以达到不改变抑制某一谐波的功能。 The effect achieved: the reactance rate can be adjusted according to the harmonic situation of the grid to achieve the best harmonic suppression effect, and the reactance rate K=X can be maintained automatically by adjusting the inductance value of the reactor when switching capacitors in groups according to the reactive power of the grid L /X C remains unchanged to achieve the function of suppressing a certain harmonic.

Claims (4)

1. the adjustable reactive power compensator of reactance is characterized in that, comprises Regulatable reactor (1) and capacitor group (2); Regulatable reactor (1) and capacitor group (2) series connection back parallel connection are on the line.
2. the adjustable reactive power compensator of reactance as claimed in claim 1 is characterized in that, capacitor group (2) comprises many group switches (2-1) and multiple unit capacitor (2-2); Parallel with one another again after each switch (2-1) and each capacitor (2-2) series connection, constitute capacitor group (2).
3. the adjustable reactive power compensator of reactance as claimed in claim 1, it is characterized in that, Regulatable reactor (1) comprises that reactor winding (1-1) and core of reactor (1-2) constitute, core of reactor (1-2) adopts variable cross-section, the cross section of iron core is reduced in the middle of the iron core a bit ofly, change the induction reactance value of reactor by the degree of saturation of change small bore magnetic circuit.
4. the adjustable reactive power compensator of reactance as claimed in claim 2 is characterized in that switch (2-1) can be A.C. contactor, controllable silicon or combination switch; If switch (2-1) is an A.C. contactor, then in ac contactor circuit, be connected in series a fuse, with protection switch.
CN2010201185093U 2010-02-25 2010-02-25 Reactance Adjustable Reactive Power Compensator Expired - Fee Related CN201797318U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102244388A (en) * 2011-07-12 2011-11-16 上海华艾软件有限公司 Reactive power compensation and filtering device with automatically adjustable inductance ratio
CN107677943A (en) * 2017-10-25 2018-02-09 广西电网有限责任公司电力科学研究院 A kind of High Voltage XLPE Power Cable and its annex fundamental wave superposition multiple-harmonic experimental rig
CN113675851A (en) * 2021-08-17 2021-11-19 西安西电电力系统有限公司 Passive filter bank with variable tuning frequency and tuning frequency control method
CN113791664A (en) * 2021-07-26 2021-12-14 广东电网有限责任公司广州供电局 Power compensation device and power compensation method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102244388A (en) * 2011-07-12 2011-11-16 上海华艾软件有限公司 Reactive power compensation and filtering device with automatically adjustable inductance ratio
CN107677943A (en) * 2017-10-25 2018-02-09 广西电网有限责任公司电力科学研究院 A kind of High Voltage XLPE Power Cable and its annex fundamental wave superposition multiple-harmonic experimental rig
CN113791664A (en) * 2021-07-26 2021-12-14 广东电网有限责任公司广州供电局 Power compensation device and power compensation method
CN113675851A (en) * 2021-08-17 2021-11-19 西安西电电力系统有限公司 Passive filter bank with variable tuning frequency and tuning frequency control method

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