CN101335456B

CN101335456B - Power distributing reactive optimizing compensation system based on GPRS and control method thereof

Info

Publication number: CN101335456B
Application number: CN2008101321358A
Authority: CN
Inventors: 罗安; 吴传平; 李强; 刘秋英; 赵伟; 于力; 黄亮亮
Original assignee: Hunan University
Current assignee: Hunan University
Priority date: 2008-07-18
Filing date: 2008-07-18
Publication date: 2011-06-15
Anticipated expiration: 2028-07-18
Also published as: CN101335456A

Abstract

The invention discloses a GPRS-based reactive power optimization compensation system of a distribution network and a control method thereof. This system is composed of a joint control system and an intelligent collaborative optimization control upper computer (industrial computer). The joint control system coordinates and controls TSC and DSTATCOM on the same compensation node through a hybrid dynamic control method, and at the same time transmits the system parameters of the node to the intelligent collaborative optimization control host computer through the GPRS wireless communication network. Intelligent collaborative optimization control The upper computer uses the multi-machine cooperative reactive power compensation method to find the optimal compensation node and compensation capacity, and sends the optimization control command to the joint compensation system. The joint compensation system compensates through the hierarchical TSC capacitor switching and continuous DSTATCOM Realize large-capacity, continuous on-site reactive power compensation. This system effectively solves the shortcomings of the current reactive power compensation system, such as poor anti-interference ability and difficult networking, and also reduces operating costs.

Description

A reactive power optimization compensation system and its control method for distribution network based on GPRS

技术领域technical field

本发明涉及一种无功优化补偿系统及其控制方法，特别涉及一种基于GPRS的配电网智能型无功优化补偿系统及其控制方法。The invention relates to a reactive power optimization compensation system and a control method thereof, in particular to a GPRS-based intelligent reactive power optimization compensation system of a power distribution network and a control method thereof.

背景技术Background technique

随着现代科学技术的发展，近年来，配电网中整流器、变频调速装置、电弧炉、电气化铁路等负荷不断增加。这些负荷的非线性、冲击性和不平衡性的用电特性，使网络中的电压、电流波形发生畸变，或引起电压波动、闪变和三相不平衡。因此，提高电网功率因数、稳定系统电压越来越多的受到人们的关注。With the development of modern science and technology, in recent years, the loads of rectifiers, frequency conversion speed control devices, electric arc furnaces, and electrified railways in distribution networks have continued to increase. The non-linear, impulsive and unbalanced power consumption characteristics of these loads distort the voltage and current waveforms in the network, or cause voltage fluctuations, flicker and three-phase unbalance. Therefore, increasing the power factor of the power grid and stabilizing the system voltage have attracted more and more people's attention.

晶闸管投切电容器(TSC)控制较简单，响应速度较快，并且具有运行时不产生谐波而且损耗较小的优点。但是它只能补偿容性无功，并且是分级调节的。单独的配电网静止同步补偿器DSTATCOM用来补偿因负荷中无功电流引起的电能质量问题或用来改善公共供电点电压质量时，主要是通过向电网注入一个与负载电流中无功电流分量大小相等方向相反的电流或者通过向电网注入一定量的无功电流以改善连接点的电压质量，因此其调节是连续的，但就目前的技术水平要做到大容量的配电网静止同步补偿器DSTATCOM，成本过高，技术难度大，不适合大规模推广使用。Thyristor switched capacitors (TSC) are simpler to control, faster in response, and have the advantages of no harmonic generation and less loss during operation. But it can only compensate capacitive reactive power, and it is regulated in stages. When the separate static synchronous compensator DSTATCOM of the distribution network is used to compensate the power quality problems caused by the reactive current in the load or to improve the voltage quality of the public power supply point, it mainly injects a reactive current component in the load current into the grid. Currents of equal size and opposite directions or by injecting a certain amount of reactive current into the grid to improve the voltage quality of the connection point, so its regulation is continuous, but as far as the current technical level is concerned, it is necessary to achieve static synchronous compensation for large-capacity distribution networks The device DSTATCOM is too expensive and technically difficult, so it is not suitable for large-scale promotion and use.

我国企业就地无功补偿电容器多采用分散的局部控制，通常不具备通讯与远程控制功能，不仅不能保证在最低的无功补偿设备投入的前提下达到全局的最优的补偿效果，也会因缺乏协调而引起各就地补偿系统的反复调节。由于企业对无功补偿设备需求数目增多，系统在潮流计算基础上进行优化求解所需计算时间较长，不能满足在线应用要求，所以目前这些应用实例多为离线分析。The on-site reactive power compensation capacitors of Chinese enterprises mostly use decentralized local control, usually do not have communication and remote control functions, not only cannot guarantee the overall optimal compensation effect under the premise of the lowest reactive power compensation equipment investment, but also Lack of coordination causes repeated adjustments of the various local compensation systems. Due to the increasing demand of enterprises for reactive power compensation equipment, the calculation time required for the system to optimize and solve based on power flow calculation is long, which cannot meet the requirements of online applications. Therefore, most of these application examples are offline analysis at present.

GPRS是一种基于GSM的无线分组交换技术，提供端到端的、广域的无线IP连接，主要适用于实时系统或通信数据量较大的准实时系统，例如配变监控、负荷控制等系统。具有网络成熟度高、费用低、基站覆盖面广以及组网灵活等优势。GPRS is a GSM-based wireless packet switching technology that provides end-to-end and wide-area wireless IP connections. It is mainly suitable for real-time systems or quasi-real-time systems with large communication data volumes, such as distribution transformer monitoring and load control systems. It has the advantages of high network maturity, low cost, wide base station coverage and flexible networking.

发明内容Contents of the invention

本发明的目的是针对现有技术存在的缺陷以及GPRS无线通讯模式所具有的优势，提供基于GPRS的配电网智能型无功优化补偿系统及其控制方法，通过协调控制TSC与DSTATCOM，分级的TSC进行无功粗调，无级的DSTATCOM进行无功精调，实现大容量、低成本的就地无功补偿连续调节系统，同时，将各就地补偿装置联网，实现多节点协同补偿，在达到最优补偿效果的前提下尽量减小无功补偿设备的投入，从而减少运行投资费用。The purpose of the present invention is to provide a GPRS-based distribution network intelligent reactive power optimization compensation system and its control method for the defects of the prior art and the advantages of the GPRS wireless communication mode. By coordinating and controlling TSC and DSTATCOM, hierarchical TSC performs rough adjustment of reactive power, and stepless DSTATCOM performs fine adjustment of reactive power to realize a large-capacity, low-cost continuous adjustment system for on-site reactive power compensation. Under the premise of achieving the optimal compensation effect, the input of reactive power compensation equipment should be reduced as much as possible, so as to reduce the operation investment cost.

为达到上述目的，本发明提供一种基于GPRS的配电网无功优化补偿系统，包括联合控制系统与智能型协同优化控制上位机，所述的联合控制系统包括GPRS模块、配电网静止同步补偿器与晶闸管投切并联电容器，所述的智能型协同优化控制上位机由GPRS终端、工控机组成，所述的联合控制系统中，配电网景之同步补偿器与晶闸管投切并联连接于电网，GPRS模块与联合控制其系统中的控制器相互连接，进行数据交换；所述的配电网静止同步补偿器由主电路、输出滤波电路、连接电抗器或变压器、控制电路和驱动电路构成，所述的晶闸管投切并联电容器由触发脉冲产生电路、晶闸管投切电路和并联电容器组构成，所述的智能型协同优化控制上位机中，GPGS终端与工控机相互连接，进行数据交换。In order to achieve the above object, the present invention provides a GPRS-based distribution network reactive power optimization compensation system, including a joint control system and an intelligent collaborative optimization control host computer, the joint control system includes a GPRS module, a distribution network static synchronization The compensator and the thyristor switch parallel capacitors. The intelligent collaborative optimization control host computer is composed of a GPRS terminal and an industrial computer. In the joint control system, the synchronous compensator of the distribution network scene is connected in parallel with the thyristor switching The power grid, GPRS module and the controller in the joint control system are connected to each other for data exchange; the static synchronous compensator of the distribution network is composed of a main circuit, an output filter circuit, a connecting reactor or a transformer, a control circuit and a drive circuit , the thyristor switching parallel capacitor is composed of a trigger pulse generating circuit, a thyristor switching circuit and a parallel capacitor bank, and in the intelligent collaborative optimization control host computer, the GPGS terminal and the industrial computer are connected to each other for data exchange.

进一步地，所述的配电网静止同步补偿器与晶闸管投切并联电容器实现单节点联合无功补偿，并通过GPRS与智能型协同优化控制上位机联网。Further, the static synchronous compensator of the distribution network and the shunt capacitor switched by the thyristor realize single-node joint reactive power compensation, and are networked with the intelligent collaborative optimization control host computer through GPRS.

相应地，基于GPRS的配电网无功优化补偿系统的控制方法，包括以下步骤：Correspondingly, the control method of the reactive power optimization compensation system of the distribution network based on GPRS includes the following steps:

(1)通过A/D采样电路采集联合控制系统所在节点的三相电压、三相负载电流瞬时值e_a、e_b、e_c，i_a、i_b、i_c；(1) Collect the instantaneous values e _a , e _b , e c , ia , i _b , and _i _c of the three _- phase voltage and three-phase load current of the node where the joint control system is located through the A/D sampling circuit;

(2)根据采样值e_a、e_b、e_c和i_a、i_b、i_c利用三相电路瞬时无功功率理论计算并求解基波有功电流和基波无功电流，并能通过GPRS将数据远传至智能型协同优化控制上位机；(2) According to the sampling values e _a , e _b , e _c and _ia , i _b , i _c use the theory of instantaneous reactive power of three-phase circuit to calculate and solve the fundamental active current and fundamental reactive current, and can pass GPRS Remotely transmit the data to the intelligent collaborative optimization control host computer;

(3)智能型协同优化控制上位机根据系统优化目标约束条件，经过跌代运算，寻求最优补偿节点及补偿容量，并通过GPRS网络将数据下传至相应联合控制系统；(3) The intelligent collaborative optimization control host computer seeks the optimal compensation node and compensation capacity according to the constraints of the system optimization target, through descending calculations, and downloads the data to the corresponding joint control system through the GPRS network;

(4)联合控制系统首先从GPRS终端所接收的数据中解析出具体补偿参数，通过联合控制器协调晶闸管投切并联电容器组及配电网静止同步补偿器实现小容量无功补偿。(4) The joint control system first analyzes the specific compensation parameters from the data received by the GPRS terminal, and through the joint controller coordinates the thyristor switching parallel capacitor bank and the static synchronous compensator of the distribution network to realize small-capacity reactive power compensation.

本发明的工作原理为：所述的联合控制器要据参数检测计算的结果将无功补偿参考电流I_q分成I_q1与I_q2两个输出，分别作为TSC与DSTATCOM的参考电流输入。DSTATCOM用来补偿因负荷中无功电流引起的电能质量问题或用来改善公共供电点电压质量时，主要是通过向电网注入一个与负载电流中无功电流分量大小相等方向相反的电流或者通过向电网注入一定量的无功电流以改善连接点的电压质量。TSC用来补偿无功的原理主要是通过反并联的晶闸管将电容器并入是网或从电网断开。当电源电压与电容器预先充电电压相等时触发晶闸管导通，以减小投切时的冲击电流。联合控制器通过混合型动态控制方法控制TSC投切电容器组数实现无功粗调、间接控制DSTATCOM参考无功电流实现无功精调。通过GPRS将各联合控制系统联网，智能型协同优化控制上位机以当前电网的实时参数作为优化补偿的依据，运用智能型协同优化控制方法经过迭代寻求最优补偿节点及补偿容量。The working principle of the present invention is as follows: the combined controller divides the reactive power compensation reference current _Iq into two outputs, _Iq1 and _Iq2 , according to the result of parameter detection and calculation, which are used as the reference current input of TSC and DSTATCOM respectively. When DSTATCOM is used to compensate the power quality problems caused by reactive current in the load or to improve the voltage quality of public power supply points, it mainly injects a current that is equal to and opposite to the reactive current component in the load current to the grid or through The grid injects a certain amount of reactive current to improve the voltage quality at the connection point. The principle of TSC used to compensate reactive power is mainly to incorporate capacitors into the grid or disconnect them from the grid through anti-parallel thyristors. When the power supply voltage is equal to the pre-charging voltage of the capacitor, the thyristor is triggered to conduct, so as to reduce the inrush current during switching. The joint controller controls the number of TSC switching capacitor groups through a hybrid dynamic control method to realize coarse reactive power adjustment, and indirectly controls DSTATCOM reference reactive current to realize reactive power fine adjustment. The joint control systems are networked through GPRS, and the intelligent collaborative optimization control host computer uses the real-time parameters of the current power grid as the basis for optimal compensation, and uses the intelligent collaborative optimization control method to iteratively seek the optimal compensation node and compensation capacity.

本发明技术效果具体在于：Technical effect of the present invention is specifically in:

(1)TSC和DSTATCOM构成联合补偿系统结构，分级的TSC进行无功粗调，无级的DSTATCOM进行无功精调，实现大容量、低成本的就地无功补偿连续调节系统。(1) TSC and DSTATCOM form a joint compensation system structure. The graded TSC performs reactive power rough adjustment, and the stepless DSTATCOM performs reactive power fine adjustment, realizing a large-capacity, low-cost on-site reactive power compensation continuous adjustment system.

(2)在电网电压跌落时，DSTATCOM能工作于直接电压控制模式，可以快速发出其最大容限的无功功率，甚至短时越限补偿无功，防止电压跌落。(2) When the grid voltage drops, DSTATCOM can work in the direct voltage control mode, which can quickly send out its maximum allowable reactive power, and even compensate reactive power for short-term over-limits to prevent voltage drops.

(3)TSC的控制与DSTATCOM的控制相互独立、没有形成闭环，因此他们同时工作时不会产生稳定性问题，方便实行独立控制；(3) The control of TSC and the control of DSTATCOM are independent of each other and do not form a closed loop, so they will not cause stability problems when they work at the same time, which is convenient for independent control;

(4)采用GPRS无线通信模式，有效地解决了现行无功补偿系统抗干扰能力差、组网困难等缺点。(4) The GPRS wireless communication mode is used to effectively solve the shortcomings of the current reactive power compensation system, such as poor anti-interference ability and difficult networking.

(5)通过GPRS实现各就地联合控制系统联网协同工作，综合电网实时状态，以当前电网实时参数作为优化决策的依据，同时运用智能型协同无功补偿方法，根据系统优化目标约束条件，由智能型协同优化控制上位机经过迭代运算协商确定最优补偿节点及所在节点的补偿容量分配。(5) Through GPRS, the local joint control systems are connected to work together, the real-time status of the power grid is integrated, and the real-time parameters of the current power grid are used as the basis for optimization decisions. Intelligent collaborative optimization controls the upper computer to determine the optimal compensation node and the compensation capacity allocation of the node through iterative calculation and negotiation.

下面结合附图对本发明作进一步的说明。The present invention will be further described below in conjunction with the accompanying drawings.

附图说明Description of drawings

图1为联合控制系统结构图。Figure 1 is a structural diagram of the joint control system.

图2为混合型动态控制框图。Figure 2 is a hybrid dynamic control block diagram.

图3为智能型协同无功补偿方法原理图。Fig. 3 is a schematic diagram of an intelligent collaborative reactive power compensation method.

具体实施方式Detailed ways

参见图1，联合控制系统主要由联合控制器、TSC与DSTATCOM系统组成。DSTATCOM部分由主电路、输出滤波电路、连接电抗器或变压器、控制电路和驱动电路构成。在中低压配电系统中，DSTATCOM的主电路拓扑采用单桥路三相电压型逆变器，电容为直流侧储能元件，为逆变器的工作提供一个稳定的直流电压。逆变器的输出电压经滤波器后经连接电抗器挂接到电网。单独的DSTATCOM用来补偿因负荷中无功电流引起的电能质量问题或用来改善公共供电点电压质量时，主要是通过向电网注入一个与负载电流中无功电流分量大小相等方向相反的电流或者通过向电网注入一定量的无功电流以改善连接点的电压质量。TSC部分主要由触发脉冲产生电路、晶闸管投切电路和并联电容器组构成。单独的TSC用来补偿无功的原理主要是通过反并联的晶闸管将电容器并入是网或从电网断开。当电源电压与电容器预先充电电压相等时触发晶闸管导通，以减小投切时的冲击电流。TSC与DSTATCOM的联合补偿主要通过联合控制器来协调，联合控制器要据参数检测计算的结果将无功补偿参考电流I_q分成I_q1与I_q2两个输出，分别作为TSC与DSTATCOM的参考电流输入。TSC的控制与DSTATCOM的控制相互独立、并未形成闭环，因而同时工作时不会产生稳定性问题。TSC的分级补偿容性无功功率可以通过DSTATCOM的微调达到容性无功功率的无级调节，而结合TSC成本低的优点，可以大大提高无功补偿装置的总容量，弥补了DSTATCOM成本高和容量难以上去的缺陷。Referring to Figure 1, the joint control system is mainly composed of joint controller, TSC and DSTATCOM system. The DSTATCOM part is composed of main circuit, output filter circuit, connecting reactor or transformer, control circuit and drive circuit. In the medium and low voltage power distribution system, the main circuit topology of DSTATCOM adopts a single-bridge three-phase voltage inverter, and the capacitor is the energy storage element on the DC side to provide a stable DC voltage for the operation of the inverter. The output voltage of the inverter is hooked up to the power grid through the connected reactor after passing through the filter. When a separate DSTATCOM is used to compensate the power quality problem caused by the reactive current in the load or to improve the voltage quality of the public power supply point, it mainly injects a current that is equal to and opposite to the reactive current component in the load current or Improve the voltage quality at the connection point by injecting a certain amount of reactive current into the grid. The TSC part is mainly composed of a trigger pulse generating circuit, a thyristor switching circuit and a parallel capacitor bank. The principle of a single TSC used to compensate reactive power is mainly to incorporate capacitors into the grid or disconnect them from the grid through anti-parallel thyristors. When the power supply voltage is equal to the pre-charging voltage of the capacitor, the thyristor is triggered to conduct, so as to reduce the inrush current during switching. The joint compensation of TSC and DSTATCOM is mainly coordinated by the joint controller. The joint controller should divide the reference current I _q of reactive power compensation into two outputs, I _q1 and I _q2 , according to the results of parameter detection and calculation, which are used as the reference current of TSC and DSTATCOM respectively. enter. The control of TSC and the control of DSTATCOM are independent of each other and do not form a closed loop, so there will be no stability problem when they work at the same time. TSC's graded compensation capacitive reactive power can achieve stepless regulation of capacitive reactive power through DSTATCOM's fine-tuning, and combined with the advantages of TSC's low cost, it can greatly increase the total capacity of reactive power compensation devices, making up for the high cost of DSTATCOM and The defect that the capacity is difficult to increase.

如图2所示为混合型动态控制框图。混合型动态控制以稳定节点电压为目的，协调DSTATCOM与TSC联合运行，所述的配电网静止同步补偿器与晶闸管投切并联电容器通过混合型动态控制方法，利用PI调节器、DSTATCOM主电路、电压调节器、联合控制器、逻辑控制器、离散滞环控制器和TSC组进行模糊控制，实现单节点联合无功补偿，并通过GPRS与智能型协同优化控制上位机联网，使系统在电流跟踪误差较大时比例控制占主导，误差减小速度较快，在误差减小到一定范围内时积分控制占主导，实现稳态无差。并且该控制器具有较强的自适应控制能力，增强了对电力系统稳定性的控制，具有满意的控制精度，易于实现数字控制，引入电流环的负反馈控制构成内闭环，以进一步提高控制精度。联合控制器是一个单输入两输出系统，将参数检测计算的结果将无功补偿参考电流I_q(I_ref)分成I_q1与I_q2两个输出，分别作为TSC与DSTATCOM的参考电流输入。TSC根据参考电流I_q2通过逻辑控制器决定投切电容器组数，离散滞环控制器可使得TSC的电容器在系统电压低于某一较低阈值时接入系统，而在系统电压高于某一较高阈值时切除，而不是在相等的阈值下投入和切除，以防止在切换电压附近振荡不定。TSC中，电容器组采用星形联结，对某一线电压为U的节点，投入一组电容器所能注入网侧的感性无功电流为：Figure 2 shows the hybrid dynamic control block diagram. The purpose of the hybrid dynamic control is to stabilize the node voltage, and coordinate the joint operation of DSTATCOM and TSC. The static synchronous compensator of the distribution network and the thyristor switching shunt capacitor use the hybrid dynamic control method to utilize the PI regulator, DSTATCOM main circuit, The voltage regulator, joint controller, logic controller, discrete hysteresis controller and TSC group perform fuzzy control to realize single-node joint reactive power compensation, and network with the intelligent collaborative optimization control host computer through GPRS to make the system track current When the error is large, the proportional control is dominant, and the error decreases faster. When the error is reduced to a certain range, the integral control is dominant, and the steady state is achieved without error. And the controller has a strong adaptive control ability, which enhances the control of the stability of the power system, has satisfactory control accuracy, and is easy to realize digital control. The negative feedback control of the current loop is introduced to form an inner closed loop to further improve the control accuracy. . The joint controller is a single-input and two-output system. The result of parameter detection and calculation divides the reactive power compensation reference current I _q (I _ref ) into two outputs, I _q1 and I _q2 , which are used as the reference current input of TSC and DSTATCOM respectively. According to the reference current I _q2 , the TSC decides the number of switching capacitor banks through the logic controller. The discrete hysteresis controller can make the capacitors of the TSC connect to the system when the system voltage is lower than a certain lower threshold, and when the system voltage is higher than a certain Cut off at a higher threshold instead of enabling and cutting off at equal thresholds to prevent oscillations around the switching voltage. In TSC, the capacitor bank is connected in star form. For a node with line voltage U, the inductive reactive current that can be injected into the grid side by putting in a group of capacitors is:

${I I}_{c c 11} = = 33 \frac{U u / / \sqrt{33}}{11 / / ω ω {C C}_{φ φ}} = = \sqrt{33} ω ω {UC UC}_{φ φ}$

在刚好达到补偿效果时投入的电容器组数为：The number of capacitor banks put in when the compensation effect is just achieved is:

$n no = = \frac{{I I}_{ref ref}}{{I I}_{c c 11}}$

取n的整数部分即为在没有过补偿前提下TSC所能投入电容器的最大组数N。Taking the integer part of n is the maximum number N of capacitors that TSC can put into capacitors without overcompensation.

剩余部分由DSTATCOM实现无功精调，其参考电流为：The remaining part is fine-tuned by DSTATCOM, and its reference current is:

I_q2＝I_ref-NI_c1 I _q2 = I _ref -NI _c1

如图3所示为智能型协同无功补偿方法原理图。根据采样值e_a、e_b、e_c和i_a、i_b、i_c利用三相电路瞬时无功功率理论计算并求解基波有功电流和基波无功电流，并通过GPRS将数据远传至智能型协同优化控制上位机，智能型协同优化控制上位机根据系统优化目标约束条件，由智能型协同优化控制上位机经过迭代运算协商确定最优补偿节点及所在节点的补偿容量分配，并通过GPRS网络将数据下传至相应联合控制系统，其寻优过程如下：Figure 3 is a schematic diagram of the intelligent collaborative reactive power compensation method. According to the sampling values e _a , e _b , e _c and _ia , i _b _{, ic} use the theory of three-phase circuit instantaneous reactive power to calculate and solve the fundamental active current and fundamental reactive current, and transmit the data remotely through GPRS To the intelligent collaborative optimization control host computer, the intelligent collaborative optimization control host computer determines the optimal compensation node and the compensation capacity allocation of the node where it is located through iterative calculation and negotiation according to the system optimization target constraints, and through The GPRS network downloads the data to the corresponding joint control system, and its optimization process is as follows:

设已选择了k个补偿点，每个点可能的补偿量为αQ_c，α＝1，2，…，m；Q_c为单位电容所提供的无功功率；α_i为第i个节点的第α个状态。Assuming that k compensation points have been selected, the possible compensation amount of each point is αQ _c , α=1, 2,..., m; Q _c is the reactive power provided by the unit capacitor; α _i is the power of the i-th node the αth state.

电网最末端节点为1，由此沿往变电所方向递增。当寻优到第i个节点时，称为第i个阶段，若其电容量α_iQ_c为一可能的最优值，则记为第i个节点的一个策略，代价为：

所有可能的α_i构成节点i的一个子策略k个阶段全过程即寻求一条最优策略路径，使得：The end node of the power grid is 1, and thus increases along the direction to the substation. When the i-th node is optimized, it is called the i-th stage. If its capacitance α _i Q _c is a possible optimal value, record is a strategy for the i-th node, the cost is:

All possible α _i constitute a sub-strategy for node i The whole process of k stages is to find an optimal strategy path, so that:

${E E.}_{max max} = = {Σ Σ}_{j j = = 11}^{k k} \underset{α α}{max max} {C C}_{j j}^{α α}$

目标函数：电能损耗节约值最大，即：Objective function: the maximum saving value of electric energy loss, that is:

$E E. = = {Σ Σ}_{i i = = 11}^{k k} (({E E.}_{li li}^{{α α}_{i i}} + + {E E.}_{ti ti}^{{α α}_{i i}})) = = {Σ Σ}_{i i = = 11}^{k k} {&Integral; &Integral;}_{00}^{T T} (({P P}_{li li}^{{α α}_{i i}} + + {P P}_{ti ti}^{{α α}_{i i}})) dt dt = = {Σ Σ}_{i i = = 11}^{k k} (({P P}_{li li}^{{α α}_{i i}} + + {P P}_{ti ti}^{{α α}_{i i}})) T T$

线路和变压器在节点i补偿后的电能损耗减小值；

The reduced value of power loss of lines and transformers after compensation at node i;

投入α_iQ_c后，属于节点i的各线段功率损耗减小值和每台变压器损耗减小值。

After inputting α _i Q _c , the power loss reduction value of each line segment belonging to node i and the reduction value of each transformer loss.

约束条件，电压约束：Constraints, voltage constraints:

U_min≤U_i≤U_max U _min ≤ U _i ≤ U _max

当节点数目很大时，上述问题的求解将变得十分复杂。为简化算法，须将方程做一定转化。工程上可以认为上述问题必定存在解，并且任一

均在一条可能存在的路径下使

达到局部最优。因为在一条支路上，每一级投入的电容主要减少上一级的无功电流，就其下一级而言没有起到降损作用，故寻优从电网末端开始。When the number of nodes is large, the solution to the above problems will become very complicated. In order to simplify the algorithm, the equation must be transformed. In engineering, it can be considered that the above problems must have solutions, and any

are used under a possible path

reach a local optimum. Because on a branch road, the capacitance invested in each stage mainly reduces the reactive current of the upper stage, and does not play a role in reducing losses for the next stage, so the optimization starts from the end of the power grid.

设第i-1阶段寻优已完毕，已投入无功功率

近似地用额定电压计算电压增量：It is assumed that the optimization of the i-1 stage has been completed, and reactive power has been invested

Approximately use the rated voltage to calculate the voltage increment:

X_ij为节点i和j到变电所两条潮流共有路径中各线段的电抗，于是电压约束条件可表示为：

X _ij is the reactance of each line segment in the two power flow common paths from node i and j to the substation, so the voltage constraint can be expressed as:

${U u}_{min min} \leq \leq {U u}_{i i} + + {Σ Σ}_{j j = = 11}^{i i} Δ Δ {U u}_{ij ij} \leq \leq {U u}_{max max}$

由此可求出节点的可能状态集。From this, the possible state set of the node can be obtained.

若原网流过第n段的无功功率为Q_n，当i-1阶段电容器投入后，流过同一线段的无功功率为Q′_n，则：If the reactive power flowing through the nth segment of the original network is Q _n , when the i-1 stage capacitor is put in, the reactive power flowing through the same segment is Q′ _n , then:

${Q Q}_{n no}^{' '} = = {Q Q}_{n no} - - {Σ Σ}_{j j = = 11}^{i i - - 11} {α α}_{j j} {Q Q}_{c c}$

此时第n段线路的功率损耗为：At this time, the power loss of the nth line is:

${P P}_{{li li}_{n no}} = = \frac{{P P}_{n no}^{22} + + {Q Q}_{n no}^{' ' 22}}{{U u}_{e e}^{22}} {R R}_{n no} \times \times 1010^{- - 33}$

Rn：n段电阻。Rn: n segment resistance.

若节点i处于α状态，则：If node i is in α state, then:

${P P}_{{li li}_{n no}}^{' '} = = \frac{{P P}_{n no}^{22} + + {(({Q Q}_{n no}^{' '} - - {α α}_{i i} {Q Q}_{c c}))}^{22}}{{U u}_{e e}^{22}} {R R}_{n no} \times \times 1010^{- - 33}$

有：have:

${P P}_{li li}^{{α α}_{i i}} = = \frac{11}{1010^{33} {U u}_{e e}^{22}} \underset{n no &Element; &Element; {N N}_{i i}}{Σ Σ} ((22 {α α}_{i i} {Q Q}_{n no}^{' '} - - {α α}_{i i}^{22} {Q Q}_{c c}^{22})) {R R}_{n no}$

代入Q′_n表达式得：Substituting into the Q′ _n expression, we get:

${P P}_{li li}^{{α α}_{i i}} = = \frac{{α α}_{i i} {Q Q}_{c c}}{1010^{33} {U u}_{e e}^{22}} ((22 \underset{n no &Element; &Element; {N N}_{i i}}{Σ Σ} {Q Q}_{n no} - - 22 {Σ Σ}_{j j = = 11}^{i i - - 11} {α α}_{j j} {Q Q}_{c c} {R R}_{ij ij} - - {α α}_{i i} {Q Q}_{c c} {R R}_{ii i}))$

R_ij：节点i和j到变电所两条潮流共有路径中的电阻；R _ij : the resistance in the common path of the two power flows from node i and j to the substation;

Ni：当节点I补偿时，补偿电流流经的各线段；Ni: when the node I is compensated, the line segments through which the compensation current flows;

n∈Ni：n属于Ni的线段。n∈Ni: n belongs to the line segment of Ni.

节点i因补偿α_iQ_c后，在变压器铁心中功率损耗的减小值：After node i is compensated for α _i Q _c , the reduced value of power loss in the transformer core:

${P P}_{ti ti}^{{α α}_{i i}} = = {Σ Σ}_{j j = = 11}^{{N N}_{t t}} \frac{{U u}_{j j}^{22} - - {(({U u}_{j j} + + Δ Δ {U u}_{ij ij}))}^{22}}{{U u}_{e e}^{22}} {P P}_{oj oj}$

忽略高次项后：After ignoring higher-order terms:

${P P}_{ti ti}^{{α α}_{i i}} = = \frac{- - 22}{{U u}_{e e}^{22}} {Σ Σ}_{j j = = 11}^{{N N}_{t t}} {P P}_{oj oj} Δ Δ {U u}_{ij ij}$

Nt：配电变压器台数。Nt: Number of distribution transformers.

因此：therefore:

${P P}_{ti ti}^{{α α}_{i i}} = = \frac{- - 22 {α α}_{i i} {Q Q}_{c c}}{1010^{33} {U u}_{e e}^{22}} {Σ Σ}_{j j = = 11}^{{N N}_{t t}} {P P}_{oj oj} {X x}_{ij ij}$

所以：so:

${E E.}_{i i}^{α α} = = T T {{\frac{{α α}_{i i} {Q Q}_{c c}}{1010^{33} {U u}_{e e}^{22}} [[22 \underset{n no &Element; &Element; {N N}_{i i}}{Σ Σ} {Q Q}_{n no} - - 22 {Σ Σ}_{j j = = 11}^{i i - - 11} {α α}_{j j} {Q Q}_{c c} {R R}_{ij ij} - - {α α}_{i i} {Q Q}_{c c} {R R}_{ii i}]] - - \frac{22 {α α}_{i i} {Q Q}_{c c}}{1010^{33} {U u}_{e e}^{22}} {Σ Σ}_{j j = = 11}^{{N N}_{t t}} {P P}_{oj oj} {X x}_{ij ij}}}$

存在状态α_i的最优策略为：The optimal strategy for existing state α _i is:

$\frac{&PartialD; &PartialD; {E E.}_{i i}^{{α α}_{i i}}}{&PartialD; &PartialD; {α α}_{i i}} = = 00$

在工程误差允许范围内解之：Solve it within the allowable range of engineering errors:

${α α}_{i i} = = [[((\underset{n no &Element; &Element; {N N}_{i i}}{Σ Σ} {Q Q}_{n no} - - {Σ Σ}_{j j = = 11}^{i i - - 11} {α α}_{j j} {Q Q}_{c c} {R R}_{ij ij} - - {Σ Σ}_{j j = = 11}^{{N N}_{t t}} {P P}_{oj oj} {X x}_{ij ij})) \frac{11}{{R R}_{ii i}}]]$

当所有节点的拓扑关系已知时，各控制器仅需T₀时刻的采样值和少量相邻控制器的参数即可独立寻优，计算量不会太大，也不会随新增节点的加入而增加很多。因为大部分计算可以同时进行，因此寻优速度非常快。寻优结束后，智能型协同优化控制上位机通过GPRS网络将分析结果下传至相应节点处的联合控制系统进行就地无功补偿。When the topological relationship of all nodes is known, each controller only needs the sampling value at time T ₀ and a small number of parameters of adjacent controllers to independently optimize, the calculation amount will not be too large, and it will not increase with the increase of new nodes. Join and increase a lot. Because most calculations can be performed simultaneously, the optimization speed is very fast. After the optimization is completed, the intelligent collaborative optimization control host computer downloads the analysis results to the joint control system at the corresponding node through the GPRS network for on-site reactive power compensation.

Claims

1. A GPRS-based distribution network reactive power optimization compensation system, including a joint control system and an intelligent collaborative optimization control upper computer, and the joint control system includes a GPRS module, a distribution network static synchronous compensator and thyristor switching Parallel capacitors, the intelligent collaborative optimization control upper computer is composed of GPRS terminal and industrial computer, in the joint control system, the synchronous compensator and thyristor switching of the distribution scene are connected in parallel to the power grid, the GPRS module and the joint The controllers in the control system are connected to each other for data exchange; the static synchronous compensator of the distribution network is composed of a main circuit, an output filter circuit, a connection reactor or a transformer, a control circuit and a drive circuit, and the thyristor input The cutting parallel capacitor is composed of a trigger pulse generating circuit, a thyristor switching circuit and a parallel capacitor bank. In the intelligent collaborative optimization control host computer, the GPGS terminal and the industrial computer are connected to each other for data exchange.

2. A kind of GPRS-based distribution network reactive power optimization compensation system according to claim 1, characterized in that: said distribution network static synchronous compensator and thyristor switching shunt capacitor through a hybrid dynamic control method, Use PI regulator, DSTATCOM main circuit, voltage regulator, joint controller, logic controller, discrete hysteresis controller and TSC group to perform fuzzy control, realize single-node joint reactive power compensation, and control through GPRS and intelligent collaborative optimization The upper computer is connected to the Internet.

3. A control method of a GPRS-based distribution network reactive power optimization compensation system, comprising the following steps:

(1) Collect the instantaneous values e _a , e _b , e c , ia , i _b , and _i _c of the three _- phase voltage and three-phase load current of the node where the joint control system is located through the A/D sampling circuit;

(2) According to the sampling values e _a , e _b , e _c and _ia , i _b , i _c use the theory of instantaneous reactive power of three-phase circuit to calculate and solve the fundamental active current and fundamental reactive current, and can pass GPRS Remotely transmit the data to the intelligent collaborative optimization control host computer;

(3) The intelligent collaborative optimization control host computer seeks the optimal compensation node and compensation capacity through descending calculation according to the system optimization target constraints, and downloads the data to the corresponding joint control system through the GPRS network;

(4) The joint control system first analyzes the specific compensation parameters from the data received by the GPRS terminal, and through the joint controller coordinates the thyristor switching parallel capacitor bank and the static synchronous compensator of the distribution network to realize small-capacity reactive power compensation.