WO2022095603A1 - 基于智能软开关与联络开关并联的转供电系统的控制方法 - Google Patents

基于智能软开关与联络开关并联的转供电系统的控制方法 Download PDF

Info

Publication number
WO2022095603A1
WO2022095603A1 PCT/CN2021/117929 CN2021117929W WO2022095603A1 WO 2022095603 A1 WO2022095603 A1 WO 2022095603A1 CN 2021117929 W CN2021117929 W CN 2021117929W WO 2022095603 A1 WO2022095603 A1 WO 2022095603A1
Authority
WO
WIPO (PCT)
Prior art keywords
distribution network
control
voltage
converter
phase
Prior art date
Application number
PCT/CN2021/117929
Other languages
English (en)
French (fr)
Inventor
陈夏
李巍巍
许树楷
李岩
喻松涛
韦甜柳
何智鹏
龙武
Original Assignee
南方电网科学研究院有限责任公司
中国南方电网有限责任公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 南方电网科学研究院有限责任公司, 中国南方电网有限责任公司 filed Critical 南方电网科学研究院有限责任公司
Publication of WO2022095603A1 publication Critical patent/WO2022095603A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
    • H02J3/0073—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks

Definitions

  • the invention relates to the technical field of power transmission and distribution, in particular to a control method for a power supply transfer system based on a parallel connection of an intelligent soft switch and a tie switch.
  • the distribution network considers the specific characteristics of equipment, protection and control, and generally operates in an open-loop mode. Therefore, when a permanent fault occurs, the fault isolation blackout area will include non-fault sections.
  • the traditional distribution network operates through circuit breakers. Further isolate the faulty power outage area, and then use the live area as the power source to restore the power supply to the non-faulty power outage area through the tie switch.
  • the intelligent soft switch that replaces the tie switch is derived.
  • the realization of the intelligent soft switch is mainly based on fully controlled power electronic devices, and its investment cost is high. Even if the access position and capacity of the intelligent soft switch are optimized through reasonable planning, the When the power grid fails to power supply, it also requires much larger capacity than normal operation. In the long run, this part of the capacity reserved by the smart soft switch causes serious waste and greatly increases the investment cost of the smart soft switch.
  • the embodiments of the present invention provide a control method for a power transfer system based on a parallel connection between an intelligent soft switch and a tie switch, so as to solve the impact caused by the potential phase difference when the tie switch is closed in the traditional power transfer mode, and use the intelligent soft switch to replace the tie switch.
  • the resulting technical problem of excessive capacity margin demand avoids the impact caused by the voltage phase difference when the tie switch is closed, and effectively reduces the capacity required for the intelligent soft switch applied to the distribution network to transfer power when a fault occurs.
  • the present invention provides a control method for a power supply transfer system based on a parallel connection between an intelligent soft switch and a tie switch.
  • the power transfer system includes: an intelligent soft switch, a tie switch, a first distribution network and a second distribution network ;
  • the first end of the tie switch is connected to the first distribution network
  • the second end of the tie switch is connected to the second distribution network
  • the intelligent soft switch is connected in parallel with the tie switch
  • the intelligent soft switch includes a first converter and a second converter, the AC side of the first converter is connected to the first end of the tie switch, and the DC side of the first converter is connected to the first end of the tie switch.
  • the DC side of the second converter is connected, and the AC side of the second converter is connected with the second end of the tie switch.
  • the control method of the power transfer system includes:
  • the intelligent soft switch judges the location of the fault when receiving the fault signal of the distribution network
  • the first converter When a fault occurs in the first distribution network, the first converter is switched from active power control to low voltage ride-through control, and the second converter maintains DC voltage control;
  • the first converter When the voltage of any phase of the first distribution network is greater than the rated value, the first converter is switched from low voltage ride-through control to transition island control; or, when the voltage of any phase of the first distribution network is When not greater than the rated value, the first converter maintains low voltage ride-through control;
  • the active power output of the intelligent soft switch is set to zero, and reactive power compensation control is started at both ends.
  • the first converter when a fault occurs in the second distribution network, the first converter is switched from active power control to DC voltage control;
  • the active power output of the intelligent soft switch is set to zero, and reactive power compensation control is started at both ends.
  • the embodiment of the present invention provides a control method for a power supply system based on the parallel connection of an intelligent soft switch and a tie switch.
  • the intelligent soft switch and the tie switch are connected in parallel to the distribution network.
  • the tie breaker is closed, thereby eliminating the impact of the tie breaker closing, effectively reducing the capacity margin requirement of the intelligent soft switch, and reducing costs.
  • FIG. 1 is a schematic structural diagram of a power transfer system based on a parallel connection between an intelligent soft switch and a tie switch provided by an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a fault in a power transfer system based on a parallel connection between an intelligent soft switch and a tie switch provided by an embodiment of the present invention
  • FIG. 3 is a schematic flowchart of a control method for a power transfer system based on a parallel connection of an intelligent soft switch and a tie switch provided by an embodiment of the present invention
  • FIG. 4 is a control principle diagram of a power transfer system based on a parallel connection between an intelligent soft switch and a tie switch provided by an embodiment of the present invention
  • Fig. 5 is a three-phase voltage waveform change diagram at both ends of an intelligent soft switch (Soft Open Points, SOP) from the occurrence of a fault to the closing process of the tie switch provided by an embodiment of the present invention
  • SOP Soft Open Points
  • Fig. 6 is the SOP fault side current and voltage waveform change diagram from the fault occurrence to the tie switch closing process provided by the embodiment of the present invention
  • FIG. 7 is a state change diagram before and after a fault of an intelligent soft switch containing a tie switch provided by an embodiment of the present invention.
  • FIG. 8 is an SOP state change diagram from a fault occurrence to a tie switch closing process provided by an embodiment of the present invention.
  • the power transfer system includes: an intelligent soft switch SOP, a tie switch S, a first distribution network DN1 and a second distribution network grid DN2;
  • the first end of the tie switch S is connected with the first distribution network DN1, the second end of the tie switch S is connected with the second distribution network DN2, and the intelligent soft switch SOP is connected in parallel with the tie switch S;
  • the intelligent soft switch SOP includes a first converter MMC1 and a second converter MMC2.
  • the AC side of the first converter MMC1 is connected to the first end of the tie switch S, and the DC side of the first converter MMC1 is connected to the second converter.
  • the DC side of the converter MMC2 is connected to the DC side, and the AC side of the second converter MMC2 is connected to the second end of the tie switch S.
  • a control method for the power transfer system includes:
  • the intelligent soft switch SOP When the intelligent soft switch SOP receives the fault signal of the distribution network, it judges the location of the fault;
  • the first converter MMC1 is switched from active power control to low voltage ride-through control, and the second converter MMC2 maintains DC voltage control;
  • the first converter MMC1 When the voltage of any phase of the first distribution network DN1 is greater than the rated value, switch the first converter MMC1 from low voltage ride-through control to transition island control; or, when the voltage of any phase of the first distribution network DN1 is not greater than the rated value value, the first converter MMC1 maintains low voltage ride-through control;
  • the first converter MMC1 is switched from active power control to DC voltage control;
  • the second converter MMC2 When the voltage of any phase of the second distribution network DN2 is greater than the rated value, the second converter MMC2 is switched from the low voltage ride-through control to the transition island control; otherwise, the second converter MMC2 maintains the low voltage ride-through control;
  • the intelligent soft switch measures the voltage and current of the system.
  • the measured variables include the DC voltage U dc , the voltages U abc,1 and U abc,2 of the two-port distribution network, the currents I abc,1 and I abc,2 , the output Active power P con,1 and P con,2 , reactive power Q con,1 and Q con,2 and the voltage phase angles ⁇ 1 and ⁇ 2 obtained through the phase-locked loop, the measured variables voltage and current are subjected to Parker transformation to obtain dq coordinates Voltages U d,1 , U q,1 , U d,2 , U q,2 and currents I d,1 , I q,1 , I d,2 , I q,2 at both ends under the system;
  • the intelligent soft switch generates control variables according to the measured variables.
  • the control variables include d-axis voltage reference values U d,ref,1 and U d,ref,2 , q-axis voltage reference values U q,ref,1 and U q,ref,2 and the phase angles ⁇ ref,1 and ⁇ ref,2 of the control voltage at both ends, and after inverse Parker transformation, the three-phase voltage reference values U a,ref,1 , U b,ref,1 , U c,ref are obtained at both ends ,1 and U a,ref,2 , U b,ref,2 , U c,ref,2 , according to the three-phase reference voltage to generate the control signals of two modular multi-level ACs to realize the power supply of the system.
  • the principle of the intelligent soft switch to generate the control variable according to the measured variable is as follows:
  • the two modular multilevel converters of the smart soft switch both contain a DC voltage control module, an active power control module, a reactive power compensation control module, a low voltage ride-through control module, a transition island control module and a voltage phase smoothing pre-synchronization control module.
  • the transition island control module directly outputs the dq axis voltage reference values U d,ref,island and U q,ref,island , as shown in expression (1):
  • U abc,RMS and U abc,RMS,ref are the effective value of the three-phase voltage on the grid side and its reference value respectively
  • U d,ref,hold and U q,ref,hold are the dq axis recorded at the moment of switching to transition island control
  • the voltage reference value can achieve a smooth transition of the control voltage.
  • the DC voltage control, active power control, low voltage ride-through control, and reactive power compensation control modules output the dq-axis current reference values I d,ref and I q,ref .
  • the low-voltage ride-through control module outputs the current reference values I d,LVRT and I q,LVRT , as shown in expression (2):
  • I SOP,max and I SOP,nom are the maximum current and rated current of the intelligent soft switch, respectively, and U RMS,nom is the rms value of the rated voltage.
  • the DC voltage control module, the active power control module and the reactive power compensation control module are all conventional and traditional control modules.
  • the current reference value is obtained by inputting the DC voltage deviation, active power deviation and grid-connected terminal voltage RMS deviation into the PI controller, respectively. The present invention will not be repeated here.
  • K p , K i are the parameters of the PI controller, ⁇ is the rated frequency of the grid, L con is the equivalent inductance of the converter, formula (3) is the formula after Laplace transformation, and s is a complex variable.
  • the phase angle obtained by the phase-locked loop is used as the phase angle of the control voltage; after the fault isolation, the phase angle of the control voltage is switched to the phase angle obtained by the output of the PI controller and the phase-locked loop on the fault side at the moment of fault isolation.
  • the sum of the angles, the phase angle of the phase-locked loop on the faulty side and the phase angle of the phase-locked loop on the non-faulty side are obtained as the input of the PI controller. In this way, before the parallel tie switch is closed, the voltage phase angle of the faulty side is smoothly transformed to be the same as that of the non-faulty side, which reduces the impact caused by closing.
  • the smooth switching method is to record the current reference value output by the active power control module at the moment of switching. , and sum this value with the output current reference value of the DC voltage control module with the reset PI controller as the final current reference value, and at the same time give a weight of 0 to 1 to the output current reference value of the active power control module, with a certain value The rate of change is reduced to 0, which realizes a smooth transition between active power control and DC voltage control, and will not cause large fluctuations or instability in the DC voltage of the smart soft switch.
  • the fault is set at fault M2 shown in Figure 2, that is, the DC voltage control side of the intelligent soft switch SOP, and the active power flow is set to be from the DC control side to the active power control side when normal, and the remaining islands after the isolated fault are simulated respectively.
  • the load is larger than the SOP capacity of the intelligent soft switch and the load is smaller than the SOP capacity.
  • Figure 5 is a diagram of the three-phase voltage waveform changes at both ends of the SOP from the fault occurrence to the closing process of the tie switch. It can be seen from Figure 5 that the control method of the present invention makes the voltage across the SOP transition smoothly, and the parallel connection There is no impact when the tie switch S is closed;
  • Figure 6 is a diagram of the current and voltage waveform changes on the SOP fault side from the fault occurrence to the closing process of the tie switch S. It can be seen from Figure 6 that the control method of the present invention makes the switching process without overcurrent generation, The voltage phase angle is smoothed to complete the pre-synchronization, and there is almost no phase angle difference when the tie switch S is closed; Fig.
  • FIG. 7 is a state change diagram of the intelligent soft switch including the tie switch before and after the failure. It can be seen from Fig. 7 that the control method of the present invention makes the switching process The DC voltage remains stable, and the voltage on the fault side can be restored to the level before the fault under the reactive power compensation control of SOP.
  • Figure 8 shows the SOP state from the fault occurrence to the closing of the tie breaker. After the fault is isolated, the voltage has about 1.2 times the power frequency overvoltage for 2 to 3 cycles, but with the transition of the island control start, The voltage is quickly regulated to the rated level. It can be seen that the two working conditions can complete the smooth switching.
  • the embodiment of the present invention provides a control method for a power transfer system based on a parallel connection between an intelligent soft switch and a tie switch.
  • the intelligent soft switch and the tie switch are connected to the distribution network in parallel, and when a fault occurs, two modularized switches in the intelligent soft switch are switched
  • the control method of the multi-level AC at the same time, the voltage phase and frequency of the fault side are adjusted to achieve smooth pre-synchronization of the voltage phase of the fault side distribution network, and the voltage phase and frequency of the fault side distribution network are consistent with the non-fault side distribution network.
  • the tie switch is closed, the impact when the tie switch is closed is eliminated and the demand for the capacity margin of the intelligent soft switch is effectively reduced.

Abstract

本发明提供了基于智能软开关与联络开关并联的转供电系统的控制方法，系统包括智能软开关、联络开关、第一配电网和第二配电网；联络开关与智能软开关并联后两端分别连接第一第二配电网，智能软开关包括第一变流器和第二变流器；智能软开关收到故障信号后判断故障位置，故障在第一配电网时，第一变流器由有功控制切换为低电压穿越控制，第二变流器保持直流电压控制；收到已隔离信号后，检测配电网电压，判断第一配电网任一相电压是否大于额定值，当大于额定值时，切换第一变流器为过渡孤岛控制；启动电压相位平滑预同步控制；第一配电网相位频率与非故障侧相同时合闸联络开关；置零智能软开关有功输出，两端启动无功补偿控制，降低了所需容量。

Description

基于智能软开关与联络开关并联的转供电系统的控制方法 技术领域
本发明涉及输配电技术领域，尤其是涉及基于智能软开关与联络开关并联的转供电系统的控制方法。
背景技术
配电网考虑设备、保护和控制的具体特点，一般都按照开环方式运行，因此当发生永久性故障停电时，故障隔离停电区会包含非故障段，传统的配电网通过断路器开关动作进一步地隔离故障停电区，再通过联络开关以带电区域为电源恢复对非故障停电区的供电。
随着分布式发电、储能和可控负载可预期地在配电网的大量接入，其明显的随机性和波动性会带来诸多问题，如电压越限、网络阻塞等，传统配电网调节手段有限，难以避免非故障区的供电中断，而且传统配电网在转供电时联络开关合闸会因为电压相位差形成冲击。因此衍生出取代联络开关的智能软开关，但是智能软开关的实现主要基于全控型电力电子器件，其投资成本较高，即使通过合理规划优化了智能软开关的接入位置和容量，在配电网故障转供电时也需要比正常运行大得多的容量，从长期考虑，智能软开关预留的这部分容量造成了严重的浪费，大大增加了智能软开关的投资成本。
发明内容
本发明实施例提供了基于智能软开关与联络开关并联的转供电系统的控制方法，以解决传统转供电模式下联络开关合闸时因电位相位差形成的冲击以及采用智能软开关替代联络开关所导致的容量裕度需求量过大的技术问题，避免了联 络开关合闸时因电压相位差形成的冲击，有效降低应用于配电网的智能软开关在故障发生时转供电所需的容量。
为了解决上述问题，本发明提供了基于智能软开关与联络开关并联的转供电系统的控制方法，所述转供电系统包括：智能软开关、联络开关、第一配电网和第二配电网；
所述联络开关第一端与所述第一配电网相连接，所述联络开关第二端与所述第二配电网相连接，所述智能软开关与所述联络开关并联；
所述智能软开关包括第一变流器和第二变流器，所述第一变流器交流侧与所述联络开关的第一端相连接，所述第一变流器直流侧与所述第二变流器直流侧相连接，所述第二变流器交流侧与所述联络开关第二端相连接。
所述转供电系统的控制方法包括：
所述智能软开关在接收到配电网故障信号时，对故障发生的位置进行判断；
当故障发生在所述第一配电网时，将所述第一变流器由有功控制切换为低电压穿越控制，所述第二变流器保持直流电压控制；
当收到故障已隔离信号时，检测所述第一配电网和所述第二配电网的电压和电流，判断所述第一配电网任一相电压是否大于额定值；
当所述第一配电网任一相电压大于额定值时，将所述第一变流器由低电压穿越控制切换为过渡孤岛控制；或者，当所述第一配电网任一相电压不大于额定值时，所述第一变流器保持低电压穿越控制；
对所述第一配电网的电压相位启动电压相位平滑预同步控制；
当所述第一配电网的相位和频率均与所述第二配电网相同时，将联络开关合闸；
将所述智能软开关有功输出置零，两端启动无功补偿控制。
作为上述方案的改进，当故障发生在所述第二配电网时，将所述第一变流器由有功控制切换为直流电压控制；
将所述第二变流器由直流电压控制切换为低电压穿越控制；
当收到故障已隔离信号时，检测所述第一配电网和所述第二配电网的电压和电流，判断所述第二配电网任一相电压是否大于额定值；
当所述第二配电网任一相电压大于额定值时，将所述第二变流器由低电压穿越控制切换为过渡孤岛控制；否则，所述第二变流器保持低电压穿越控制；
对所述第二配电网的电压相位启动电压相位平滑预同步控制；
当所述第二配电网的相位和频率均与所述第一配电网相同时，将所述联络开关合闸；
将所述智能软开关有功输出置零，两端启动无功补偿控制。
本发明对比现有技术有如下有益效果，本发明实施例提供了基于智能软开关与联络开关并联的转供电系统的控制方法，智能软开关与联络开关并联接入配电网，当故障发生时，通过切换智能软开关中两个模块化多电平交流器的控制方式，同时对故障侧电压相位和频率进行调整以实现故障侧配电网电压相位平滑预同步，并在故障侧配电网电压相位和频率与非故障侧配电网一致时，联络开关合闸，从而消除联络开关合闸时的冲击以及有效降低了智能软开关容量裕度需求量，降低了成本。
附图说明
图1是本发明实施例提供的基于智能软开关与联络开关并联的转供电系统的结构示意图；
图2是本发明实施例提供的基于智能软开关与联络开关并联的转供电系统故障示意图；
图3是本发明实施例提供的基于智能软开关与联络开关并联的转供电系统的控制方法的流程示意图；
图4是本发明实施例提供的基于智能软开关与联络开关并联的转供电系统的控制原理图；
图5是本发明实施例提供的从故障发生到联络开关合闸过程的智能软开关(Soft Open Points，SOP)两端三相电压波形变化图；
图6是本发明实施例提供的从故障发生到联络开关合闸过程的SOP故障侧电流电压波形变化图；
图7是本发明实施例提供的含联络开关的智能软开关故障前后状态变化图；
图8是本发明实施例提供的从故障发生到联络开关合闸过程的SOP状态变化图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例提供的基于智能软开关与联络开关并联的转供电系统的控制方法，参见图1，转供电系统包括：智能软开关SOP、联络开关S、第一配电网DN1和第二配电网DN2；
联络开关S第一端与第一配电网DN1相连接，联络开关S第二端与第二配电网DN2相连接，智能软开关SOP与联络开关S并联；
智能软开关SOP包括第一变流器MMC1和第二变流器MMC2，第一变流器MMC1交流侧与联络开关S的第一端相连接，第一变流器MMC1直流侧与第二变流器MMC2直流侧相连接，第二变流器MMC2交流侧与联络开关S第二端相连接。
图2是本发明实施例提供的基于智能软开关与联络开关并联的转供电系统故障示意图，参见图3，转供电系统的控制方法，包括：
智能软开关SOP在接收到配电网故障信号时，对故障发生的位置进行判断；
当故障发生在图2的故障M1所在位置，将第一变流器MMC1由有功控制切换为低电压穿越控制，第二变流器MMC2保持直流电压控制；
当收到故障已隔离信号时，检测第一配电网DN1和第二配电网DN2的电压和电流，判断第一配电网DN1任一相电压是否大于额定值；
当第一配电网DN1任一相电压大于额定值时，将第一变流器MMC1由低电压穿越控制切换为过渡孤岛控制；或者，当第一配电网DN1任一相电压不大于额定值时，第一变流器MMC1保持低电压穿越控制；
对第一配电网DN1的电压相位启动电压相位平滑预同步控制；
当第一配电网DN1的相位和频率均与第二配电网DN2相同时，将联络开关S合闸；
将智能软开关SOP有功输出置零，两端启动无功补偿控制。
作为上述方案的改进，当故障发生在图2的故障M2所在位置，将第一变流器MMC1由有功控制切换为直流电压控制；
将第二变流器MMC2由直流电压控制切换为低电压穿越控制；
当收到故障已隔离信号时，检测第一配电网DN1和第二配电网DN2的电压和电流，判断第二配电网DN2任一相电压是否大于额定值；
当第二配电网DN2任一相电压大于额定值时，将第二变流器MMC2由低电压穿越控制切换为过渡孤岛控制；否则，第二变流器MMC2保持低电压穿越控制；
对第二配电网DN2的电压相位启动电压相位平滑预同步控制；
当第二配电网DN2的相位和频率均与第一配电网DN1相同时，将联络开关S合闸；
将智能软开关SOP有功输出置零，两端启动无功补偿控制。
为了更好地理解本发明的技术方案，下面对本发明实施例提供的一种转供电系统的原理进行介绍，具体如下：
智能软开关对系统进行电压、电流进行测量，测量变量包含了直流电压U dc、两端口配电网的电压U abc,1和U abc,2、电流I abc,1和I abc,2、输出有功P con,1和P con,2、无功Q con,1和Q con,2以及经过锁相环获取的电压相角θ 1和θ 2，将测量变量电压、电流经过派克变换得到dq坐标系下的两端电压U d,1、U q,1、U d,2、U q,2和两端电流I d,1、I q,1、I d,2、I q,2；
智能软开关根据测量变量生成控制变量，控制变量有d轴电压参考值U d,ref,1和U d,ref,2、q轴电压参考值U q,ref,1和U q,ref,2以及两端控制电压的相角θ ref,1和θ ref,2，再经过反派克变换后得到两端三相电压参考值U a,ref,1、U b,ref,1、U c,ref,1和U a,ref,2、U b,ref,2、U c,ref,2，根据三相参考电压生成两个模块化多电平交流器的控制信号，实现系统的转供电。
其中，智能软开关根据测量变量生成控制变量的原理如下：
智能软开关的两个模块化多电平变流器都包含直流电压控制模块、有功控制模块、无功补偿控制模块、低电压穿越控制模块、过渡孤岛控制模块和电压相位平滑预同步控制模块。
其中过渡孤岛控制模块直接输出dq轴电压参考值U d,ref,island和U q,ref,island，如表达式(1)所示：
Figure PCTCN2021117929-appb-000001
其中U abc,RMS和U abc,RMS,ref分别是网侧三相电压有效值及其参考值，U d,ref,hold和U q,ref,hold是切换为过渡孤岛控制瞬间记录的dq轴电压参考值，可实现控制电压的平滑过渡。
直流电压控制、有功控制、低电压穿越控制、无功补偿控制模块输出的是dq轴电流参考值I d,ref和I q,ref。
低电压穿越控制模块输出电流参考值I d,LVRT和I q,LVRT，如表达式(2)所示：
Figure PCTCN2021117929-appb-000002
其中，I SOP,max和I SOP,nom分别为智能软开关的最大电流和额定电流，U RMS,nom为额定电压有效值。
直流电压控制模块、有功控制模块以及无功补偿控制模块都是常规传统的控制模块，分别是通过直流电压偏差、有功功率偏差和并网端电压有效值偏差输入PI控制器中获得电流参考值，本发明不再赘述。
通过当前的电流参考值与测量电流的作差，再输入电流内环PI控制器，结合相应的前馈项获得dq轴电压参考值U d,ref和U q,ref，其表达式如下：
Figure PCTCN2021117929-appb-000003
其中，K p、K i是PI控制器的参数，ω是电网额定频率，L con是变流器等效电感，公式(3)是经拉普拉斯变换后的公式，s是复变量。
在常规运行工况下，采用锁相环获得的相角作为控制电压的相角；在故障隔离后，控制电压的相角切换为PI控制器的输出与故障隔离瞬间故障侧锁相环所得相角之和，故障侧锁相环获得相角与非故障侧锁相环相角作差作为PI控制器的输入。这样就使得并联联络开关合闸前，故障侧电压相角平滑变换至与非故障侧相同，减小了合闸带来的冲击。
当故障发生在直流电压控制侧的电网时，需要将非故障侧有功控制切换为直流电压控制，同样需要采用平滑切换的方式；平滑切换的方式为，切换瞬间记录有功控制模块输出的电流参考值，并将该值与重置了PI控制器的直流电压控制模块输出电流参考值求和，作为最终的电流参考值，同时赋予有功控制模块输出电流参考值一个0到1的权重，以一定的变化率减小到0，实现了有功控制与直流电压控制的平滑过渡，不会造成智能软开关直流电压的大幅波动或失稳。
为了更好地说明本发明的技术方案能够消除联络开关合闸时的冲击，取其中两种工况的实验仿真结果进行进一步说明，具体如下：
本实验设置故障位于图2所示的故障M2处，即智能软开关SOP的直流电压控制侧，并设正常时有功流向为直流控制侧到有功控制侧，同时分别仿真了隔离故障后，剩余孤岛负荷大于智能软开关SOP容量以及小于SOP容量两种情况。
当孤岛负荷大于SOP容量时，图5为故障发生到联络开关合闸过程的SOP两端三相电压波形变化图，由图5可看出，本发明控制方法使得SOP两端电压 平滑过渡，并联联络开关S合闸时无冲击；图6为故障发生到联络开关S合闸过程的SOP故障侧电流电压波形变化图，由图6可看出，本发明控制方法使得切换过程无过电流产生，电压相角平滑完成预同步，联络开关S合闸时几乎无相角差；图7为含联络开关的智能软开关故障前后状态变化图，由图7可看出，本发明控制方法使得切换过程直流电压保持稳定，在SOP的无功补偿控制下故障侧电压可恢复故障前水平。
当孤岛负荷小于SOP容量时，图8为故障发生到联络开关合闸的SOP状态，在故障隔离后电压存在2～3个周期的约1.2倍工频过电压，但随着过渡孤岛控制启动，电压快速调节至额定水平。由此可见，两种工况均可完成平滑切换。
本发明实施例提供了基于智能软开关与联络开关并联的转供电系统的控制方法，智能软开关与联络开关并联接入配电网，当故障发生时，通过切换智能软开关中两个模块化多电平交流器的控制方式，同时故障侧电压相位和频率进行调整以实现故障侧配电网电压相位平滑预同步，并在故障侧配电网电压相位和频率与非故障侧配电网一致时，联络开关合闸，从而消除联络开关合闸时的冲击以及有效降低了智能软开关容量裕度需求量。
以上所揭露的仅为本发明较佳实施例而已，当然不能以此来限定本发明之权利范围，本领域普通技术人员可以理解实现上述实施例的全部或部分流程，并依本发明权利要求所作的等同变化，仍属于发明所涵盖的范围。

Claims (2)

  1. 基于智能软开关与联络开关并联的转供电系统的控制方法，其特征在于，所述转供电系统包括：智能软开关、联络开关、第一配电网和第二配电网；
    所述联络开关第一端与所述第一配电网相连接，所述联络开关第二端与所述第二配电网相连接，所述智能软开关与所述联络开关并联；
    所述智能软开关包括第一变流器和第二变流器，所述第一变流器交流侧与所述联络开关的第一端相连接，所述第一变流器直流侧与所述第二变流器直流侧相连接，所述第二变流器交流侧与所述联络开关第二端相连接；
    所述基于智能软开关与联络开关并联的转供电系统的控制方法包括：
    所述智能软开关在接收到配电网故障信号时，对故障发生的位置进行判断；
    当故障发生在所述第一配电网时，将所述第一变流器由有功控制切换为低电压穿越控制，所述第二变流器保持直流电压控制；
    当收到故障已隔离的信号时，检测所述第一配电网和所述第二配电网的电压和电流，判断所述第一配电网任一相电压是否大于额定值；
    当所述第一配电网任一相电压大于额定值时，将所述第一变流器由低电压穿越控制切换为过渡孤岛控制；或者，当所述第一配电网任一相电压不大于额定值时，所述第一变流器保持低电压穿越控制；
    对所述第一配电网的电压相位启动电压相位平滑预同步控制；
    当所述第一配电网的相位和频率均与所述第二配电网相同时，将联络开关合闸；
    将所述智能软开关有功输出置零，两端启动无功补偿控制。
  2. 如权利要求1所述的基于智能软开关与联络开关并联的转供电系统的控制方法，其特征在于，还包括：
    当故障发生在所述第二配电网时，将所述第一变流器由有功控制切换为直流 电压控制，将所述第二变流器由直流电压控制切换为低电压穿越控制；
    当收到故障已隔离的信号时，检测所述第一配电网和所述第二配电网的电压和电流，判断所述第二配电网任一相电压是否大于额定值；
    当所述第二配电网任一相电压大于额定值时，将所述第二变流器由低电压穿越控制切换为过渡孤岛控制；或者，当第二配电网任一相电压不大于额定值时，所述第二变流器保持低电压穿越控制；
    对所述第二配电网的电压相位启动电压相位平滑预同步控制；
    当所述第二配电网的相位和频率均与所述第一配电网相同时，将所述联络开关合闸；
    将所述智能软开关有功输出置零，两端启动无功补偿控制。
PCT/CN2021/117929 2020-11-04 2021-09-13 基于智能软开关与联络开关并联的转供电系统的控制方法 WO2022095603A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202011218914.7 2020-11-04
CN202011218914.7A CN112448388B (zh) 2020-11-04 2020-11-04 基于智能软开关与联络开关并联的转供电系统的控制方法

Publications (1)

Publication Number Publication Date
WO2022095603A1 true WO2022095603A1 (zh) 2022-05-12

Family

ID=74735684

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/117929 WO2022095603A1 (zh) 2020-11-04 2021-09-13 基于智能软开关与联络开关并联的转供电系统的控制方法

Country Status (2)

Country Link
CN (1) CN112448388B (zh)
WO (1) WO2022095603A1 (zh)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112448388B (zh) * 2020-11-04 2022-02-22 南方电网科学研究院有限责任公司 基于智能软开关与联络开关并联的转供电系统的控制方法
CN113315123A (zh) * 2021-05-31 2021-08-27 西安交通大学 一种背靠背柔性合环开关状态切换方法
CN116544948B (zh) * 2023-06-26 2024-01-23 南方电网科学研究院有限责任公司 一种智能软开关与并联联络开关的转供电方法和系统

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160197558A1 (en) * 2013-09-04 2016-07-07 General Electric Technology Gmbh Power converter
CN107196297A (zh) * 2017-06-28 2017-09-22 国网天津市电力公司 基于snop的柔性配电网中分布式电源最大准入容量计算方法
CN108767853A (zh) * 2018-06-20 2018-11-06 山东大学 混合型背靠背智能软开关拓扑结构、控制系统及控制方法
CN109698500A (zh) * 2019-01-24 2019-04-30 广东电网有限责任公司 一种基于智能软开关的配电网供电可靠性提升方法
CN110148954A (zh) * 2019-05-24 2019-08-20 青岛大学 一种基于sop的配电网控制方法
CN112448388A (zh) * 2020-11-04 2021-03-05 南方电网科学研究院有限责任公司 基于智能软开关与联络开关并联的转供电系统的控制方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8861238B2 (en) * 2011-08-25 2014-10-14 North Carolina State University Isolated soft-switch single-stage AC-DC converter
CN207339264U (zh) * 2017-08-03 2018-05-08 贵州电网有限责任公司电力科学研究院 一种直流配电中心控制系统
CN208738913U (zh) * 2018-08-15 2019-04-12 广东安朴电力技术有限公司 一种模块化多电平变流器结构的合环转供电sop装置及系统
CN109494710A (zh) * 2018-10-15 2019-03-19 广东安朴电力技术有限公司 一种合环转供电的调相调压装置、系统及方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160197558A1 (en) * 2013-09-04 2016-07-07 General Electric Technology Gmbh Power converter
CN107196297A (zh) * 2017-06-28 2017-09-22 国网天津市电力公司 基于snop的柔性配电网中分布式电源最大准入容量计算方法
CN108767853A (zh) * 2018-06-20 2018-11-06 山东大学 混合型背靠背智能软开关拓扑结构、控制系统及控制方法
CN109698500A (zh) * 2019-01-24 2019-04-30 广东电网有限责任公司 一种基于智能软开关的配电网供电可靠性提升方法
CN110148954A (zh) * 2019-05-24 2019-08-20 青岛大学 一种基于sop的配电网控制方法
CN112448388A (zh) * 2020-11-04 2021-03-05 南方电网科学研究院有限责任公司 基于智能软开关与联络开关并联的转供电系统的控制方法

Also Published As

Publication number Publication date
CN112448388A (zh) 2021-03-05
CN112448388B (zh) 2022-02-22

Similar Documents

Publication Publication Date Title
WO2022095603A1 (zh) 基于智能软开关与联络开关并联的转供电系统的控制方法
Cao et al. Operating principle of Soft Open Points for electrical distribution network operation
AU2005267580B2 (en) Power flow controller responsive to power circulation demand for optimizing power transfer
de Toledo et al. Multiple infeed short circuit ratio-aspects related to multiple HVDC into one AC network
CN106849172B (zh) 光储交直流微网中的并离网无缝切换策略
Papangelis et al. Stability of a voltage source converter subject to decrease of short-circuit capacity: A case study
WO2022088554A1 (zh) 一种多端口交流电网柔性互联装置及其控制方法和系统
Wang et al. A comprehensive improved coordinated control strategy for a STATCOM integrated HVDC system with enhanced steady/transient state behaviors
Liu et al. Seamless transfer scheme with unified control core for paralleled systems
Chen et al. Coordination of SMES, SFCL and distributed generation units for micro-grid stability enhancement via wireless communications
Xin et al. AC fault ride-through coordinated control strategy of LCC-MMC hybrid DC transmission system connected to passive networks
Rodrigues et al. Fault-ride-through strategies for grid-tied and grid-forming smart-transformers suited for islanding and interconnected operation
Feng et al. Optimal power allocation strategy for black start in VSC-MTDC systems considering dynamic impacts
Smith et al. A secondary strategy for unbalance consensus in an islanded voltage source converter-based microgrid using cooperative gain control
Mehedi et al. Reducing fault current by using FACTS devices to improve electrical power flow
Bahravar et al. Modeling and coordinated control of IPFC and SVC to improve the low frequency oscillation damping
KR100501884B1 (ko) 분산전원 시스템
Xi et al. STATCOM operation strategy under power system faults
Yang et al. An Improved Master-Slave Control Strategy for Automatic DC Voltage Control Under the Master Station Failure in MTDC System
Fang et al. BTB DC link modeling, control, and application in the segmentation of AC interconnections
Jalali et al. Dynamic voltage stability procurement of power systems using energy storage devices
Bhattacharya et al. A practical operation strategy for STATCOM under single line to ground faults in the power system
Langwasser Management and Protection of High-Voltage Direct Current Systems Based on Modular Multilevel Converters
Zhang et al. Multi-Ports Unified Power Quality Conditioner for Active Distribution Network
KR100774023B1 (ko) 4레그 인버터방식을 이용한 무정전 전원장치 및 이의제어방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21888302

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 26.09.2023)