高压直流输电系统的实时数字仿真研究
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摘要
直流输电方式及其相关技术在我国电网建设中已得到越来越广泛的重视。相对交流输电而言，直流输电在大功率、远距离、海底电缆送电和交流系统间非同步互联等方面有着明显的优越性。灵宝背靠背直流联网工程是我国第一个落实引进技术转让、进而实现完全国产化的依托工程。该项目联接华中220kV系统和西北330kV系统，配备了两套基于不同技术的极控系统。为确保工程设备在实际投产时安全可靠的运行，必须对这两套系统分别进行仿现场测试，以考验装置是否能够满足设计要求。本文应用电力系统实时数字仿真器RTDS(Real-time Digital Simulator)建立了与知己现场环境相仿的一次系统试验模型，并在此模型的基础上对工程的二次系统装置，包括换流站的运行人员控制系统、直流极控系统、交直流站控系统和直流极保护等，进行了功能测试和性能参数调整。论文的具体内容如下：
首先，论文介绍了直流输电的基本原理及对其进行数值仿真的基本方法。数值计算仿真方法主要是基于H．W．Dommel的经典电磁暂态理论。根据Dommel的理论，所有储能元件都可用梯形积分法将描述其支路特性的微分方程转化为一个电阻并联一个电流源的计算机离散模型。同时由贝杰龙理论可知，所有的长线分布参数都可根据前反行波的传播机理，简化为由两个集中参数的端口网络构成的计算机模型。这样一个系统就可以被转化成一个便于计算机计算的由纯电阻和电流源构成的网络。对于这一网络容易建立实现节点代数方程并求得系统各状态变量的数值解。
其次，论文详细论述了在RTDS上建立的灵宝背靠背直流联网工程试验回路一次模型和对一些特殊问题的处理方法。由于高压直流输电的一次系统不可能脱离二次控制系统而运行，因此为了在被试装置接入试验回路之前使一次模型的可行性得到验证，本文还在RTDS上利用其核心软件EMTDC的控制元件模块搭建了通用的直流极控系统，以使试验模型能够脱离外部制装置独立运行。并且在基于内部控制模型的情况下，对一次模型运行在各种工况下的状况进行了校验。
最后，在RTDS与被试控制保护装置连接后，按照“测试试验大纲”对两种控制保护系统分别进行了测试试验，并针对几种不同控制系统的实验结果进行了研究比较。
经过上述对试验方案和实验结果的归纳总结，可以得出结论：此次所建RTDS模型，能够满足控制保护系统整体功能及各单项性能的测试要求，是可行的。
In China much attention has been paid to the application of the High Voltage Direct Current (HVDC) transmission. Compared to ac technology, the DC power system offers many advantages and benefits to the overall power system especially in submarine power cable systems. long- distance power transmission and interconnection between different ac power networks. LingBao back-to-back HVDC project is the first one whose DC control and protection equipments are all made by Chinese manufacturer. This system will connect HuaZhong 220kV electric-network to the XiBei 330kV system. To ensure the utilities of the project will work well after they are set in the station, much efforts should be made to extensively test proposed control principles as well as the actual control hardware before installation in the converter terminal stations. This paper presents a study on the simulation of LingBao HVDC system with the real-time digital simulator. Based on this model, physical controls are connected to the simulator and a clos
ed loop operation with external control is taken.
Firstly, the paper describes the theory of electromagnetic transient simulation and HVDC transmission. Electromagnetic transient simulation is based on concepts introduced by H.W.DofRrael in his classic paper of 1969. According to the Dommel algorithm, all passive components within the network can be converted to an equivalent resistor in parallel with a current source applying the trapezoidal rule of integration. The equivalent resistance value is time invariant and depends on the component type and its parameters. The current injection on the other hand is time and history dependent and must be updated each time a new system state is produced. Thus, the power system can be turned into a network composed of resistors and current soiaces. It easy to set up the nodal algebraic equation of this network .With solving the equation, we can get every state variable of the power network.
Secondly, the thesis expounds the test model setting up at RTDS in detail and some special tteateaent methods to some certain problems. Because of the HVDC system impossible to ran without control system, so in order to make the feasibility of the RTDS model verify before the device inserting the test circuit, a DC control system is put up using typical or generic coflfteols modeled internally. In this way, the test model can break away from the external equipments and run independently.
Finally, a function test has been taken on the equipments according to the "testing outMnes" after the RTDS was joined with the control and protection utilities. Many practical studies involving HVDC systems and controls have been carried out using real time simulation. Studies have been performed on the experiment results both for developmental purposes and for testing purposes.
After summing up to the testing program and experimental results, the model built on RTDS is proved to accord with the demands for this experiment which tests the whole function of the system and every individual event performance.
首先，论文介绍了直流输电的基本原理及对其进行数值仿真的基本方法。数值计算仿真方法主要是基于H．W．Dommel的经典电磁暂态理论。根据Dommel的理论，所有储能元件都可用梯形积分法将描述其支路特性的微分方程转化为一个电阻并联一个电流源的计算机离散模型。同时由贝杰龙理论可知，所有的长线分布参数都可根据前反行波的传播机理，简化为由两个集中参数的端口网络构成的计算机模型。这样一个系统就可以被转化成一个便于计算机计算的由纯电阻和电流源构成的网络。对于这一网络容易建立实现节点代数方程并求得系统各状态变量的数值解。
其次，论文详细论述了在RTDS上建立的灵宝背靠背直流联网工程试验回路一次模型和对一些特殊问题的处理方法。由于高压直流输电的一次系统不可能脱离二次控制系统而运行，因此为了在被试装置接入试验回路之前使一次模型的可行性得到验证，本文还在RTDS上利用其核心软件EMTDC的控制元件模块搭建了通用的直流极控系统，以使试验模型能够脱离外部制装置独立运行。并且在基于内部控制模型的情况下，对一次模型运行在各种工况下的状况进行了校验。
最后，在RTDS与被试控制保护装置连接后，按照“测试试验大纲”对两种控制保护系统分别进行了测试试验，并针对几种不同控制系统的实验结果进行了研究比较。
经过上述对试验方案和实验结果的归纳总结，可以得出结论：此次所建RTDS模型，能够满足控制保护系统整体功能及各单项性能的测试要求，是可行的。
In China much attention has been paid to the application of the High Voltage Direct Current (HVDC) transmission. Compared to ac technology, the DC power system offers many advantages and benefits to the overall power system especially in submarine power cable systems. long- distance power transmission and interconnection between different ac power networks. LingBao back-to-back HVDC project is the first one whose DC control and protection equipments are all made by Chinese manufacturer. This system will connect HuaZhong 220kV electric-network to the XiBei 330kV system. To ensure the utilities of the project will work well after they are set in the station, much efforts should be made to extensively test proposed control principles as well as the actual control hardware before installation in the converter terminal stations. This paper presents a study on the simulation of LingBao HVDC system with the real-time digital simulator. Based on this model, physical controls are connected to the simulator and a clos
ed loop operation with external control is taken.
Firstly, the paper describes the theory of electromagnetic transient simulation and HVDC transmission. Electromagnetic transient simulation is based on concepts introduced by H.W.DofRrael in his classic paper of 1969. According to the Dommel algorithm, all passive components within the network can be converted to an equivalent resistor in parallel with a current source applying the trapezoidal rule of integration. The equivalent resistance value is time invariant and depends on the component type and its parameters. The current injection on the other hand is time and history dependent and must be updated each time a new system state is produced. Thus, the power system can be turned into a network composed of resistors and current soiaces. It easy to set up the nodal algebraic equation of this network .With solving the equation, we can get every state variable of the power network.
Secondly, the thesis expounds the test model setting up at RTDS in detail and some special tteateaent methods to some certain problems. Because of the HVDC system impossible to ran without control system, so in order to make the feasibility of the RTDS model verify before the device inserting the test circuit, a DC control system is put up using typical or generic coflfteols modeled internally. In this way, the test model can break away from the external equipments and run independently.
Finally, a function test has been taken on the equipments according to the "testing outMnes" after the RTDS was joined with the control and protection utilities. Many practical studies involving HVDC systems and controls have been carried out using real time simulation. Studies have been performed on the experiment results both for developmental purposes and for testing purposes.
After summing up to the testing program and experimental results, the model built on RTDS is proved to accord with the demands for this experiment which tests the whole function of the system and every individual event performance.
引文
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[2] 林永生、胡良珍、严朗威著，高压直流输电，上海科学技术出版社，1980
[3] 李兴源著，高压直流输电系统的运行和控制，科学出版社，1998
[4] 向大为，三峡电站及其交、直流混合输电系统的建模与仿真，重庆大学硕士学位论文，2002
[5] 杨卫东，多馈入直流输电系统的控制策略研究，浙江大学硕士学位论文，2001
[6] 赵美莲，交直流并联输电系统直流功率调制的研究，广西大学硕士学位论文，2002
[7] 黄方能，天广交直流并联输电系统的谐波分析，广西大学硕士学位论文，2001
[8] 张桂斌，新型直流输电及其相关技术研究，浙江大学硕士学位论文，2001
[9] 姚谦，直流输电控制和保护系统的脉冲发生器的研究，华北电力大学硕士学位论文，2001
[10] 李良仁，高压直流输电系统的控制和滤波研究，哈尔滨工业大学硕士学位论文，2001
[11] 常乃超，基于详细模型的HVDC系统控制研究，哈尔滨工业大学硕士学位论文，2001
[12] 王学强．、黄立滨．、崔伟，纵差线路保护装置RTDS实验方案设计，继电器，2003年年09期，26～30页
[13] 郑三立．、韩英铎．、雷宪章，NETOMAC在电力系统实时仿真中的应用，电网技术 2003年01期，19～21页
[14] 何仰赞、温增银、汪馥英等著，电力系统分析(下)，华中理工大学出版社，1996
[15] 倪以信、陈寿孙、张宝霖著，动态电力系统的理论和分析，清华大学出版社，2002
[16] 邵震霞，利用高压直流输电控制提高电力系统稳定性研究，四川大学硕士学位论文，2002
[17] 河田谦一，大容量直流输电技术的应用，国际电力，1999年01期，38～43页
[18] 陆治国，任震，背靠背高压直流输电系统的稳态仿真研究，中国电机工程学报，1999，Vol．19，No．4：23-25
[19] 张三洪、汪馥英、何仰赞等，直流系统的暂态仿真，华中理工大学学报，1994，Vol．22，No．7：73-77
[20] 周双喜，吕佳丽，张元鹏，商流输电对电压稳定性的影响，清华大学学报(自然科学版)，1999，Vol．39，No．3：4-7
[21] 徐政，联于弱交流系统的直流的交流输电特性研究(一)、(二)，电网技术．1997，Vol．21，No．1：12-16；No．3：1-9
[22] 周乐容，高压直流输电的现状及发展，广东电力，1997年第5期，1—9页
[23] 邵震霞、李兴源，高压直流输电系统控制器数字仿真实现方法，四川大学学报(工程科学版)，2002，Vol．34，No．3：80-83
[24] 夏道止、沈赞著，高压直流输电系统的谐波分析及滤波，北京水利水电出版社
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