Due to the large scale and large number of wind turbines in existing wind farms, coupled with the inherent difficulty in modeling and simulating wind turbines, wind farm electromagnetic transient simulation efficiency is low. To address these issues, this paper proposes a fine-grained decoupling and parallel simulation method for direct-drive wind turbines based on the principle of semi-implicit delay decoupling to achieve efficient electromagnetic transient simulation of direct-drive wind turbines. First, using the matrix splitting principle, the direct-drive wind turbine is grouped according to state variables and decomposed into multiple subsystems. A semi-implicit delay decoupling method is then used to achieve time delay decoupling between different state variable groups within the direct-drive wind turbine. Based on the semi-implicit delay decoupling recursive format, a decoupled model for the direct-drive wind turbine is constructed, its characteristics are analyzed, and the computational sequence and process are designed. Simulation results from a practical example demonstrate that this method improves the computational efficiency of electromagnetic transient simulation of direct-drive wind turbines while maintaining high simulation accuracy.

Based on the principle of semi-implicit delay decoupling, this paper proposes a simulation calculation method for the decoupling model of photovoltaic power generation units. Firstly, for the state equations of each device of the photovoltaic power generation unit, the half-step time-delay decoupling model of each device is constructed by using matrix splitting and delay decoupling techniques. Then, the calculation of the relevant decoupling model parameters was simplified, keeping the system admittance matrix constant and further improving the computational efficiency. Finally, the accuracy and computational efficiency of the established model were verified through an example of a photovoltaic power station. Compared with the detailed model in Power Systems Computer Aided Design (PSCAD), the error of the model used in this paper is approximately 0.6%. The computational efficiency is increased by about 30% in serial operation and several times in parallel operation.

The conventional memory allocation method in distributed heterogeneous memory pool mainly uses the Spark Shuffle skew tuning execution algorithm to calculate the allocation parameters, which is vulnerable to changes in temporary storage task nodes, resulting in excessive memory overflow in the pool. Therefore, a memory allocation method in distributed heterogeneous memory pool using reinforcement learning is proposed. That is, the memory allocation manager in the distributed heterogeneous memory pool is designed by using reinforcement learning, and the memory transmission optimization mechanism in the distributed heterogeneous memory pool is generated, thus realizing the memory allocation in the heterogeneous memory pool. The experimental results show that after using the memory allocation method in the distributed heterogeneous memory pool reinforcement learning pool designed in this paper, the memory overflow in the pool under different types of memory pools is low, which proves that the designed memory allocation method has good allocation effect, high efficiency, and certain application value, and has made certain contributions to improving the quality of distributed heterogeneous storage.

Conventional high-performance memory mapping data multi-layer allocation methods mainly use SOM (Self organizing maps) improved self-organizing mapping algorithm to extract data allocation characteristics, which is vulnerable to the impact of cluster topology, resulting in low data allocation utilization. Therefore, a high-performance memory mapping data multi-layer allocation method is designed considering real-time performance adaptation. That is, a dynamic scheduling and allocation model for high-performance memory mapping data is constructed, and a multi-layer allocation algorithm for high-performance memory mapping data is designed considering real-time performance adaption, thus completing the multi-layer allocation of high-performance memory mapping data. The experimental results show that the designed real-time performance adaptive high-performance memory mapping data multi-layer allocation method has a high data allocation utilization rate, good allocation effect, meets the real-time requirements of data allocation, and makes some contributions to the realization of dynamic data resource allocation.

The new power system contains a lot of electrical components with independent zero-sequence paths. However, based on the traditional Thévenin's equivalent modeling method, which directly uses the total voltage of external nodes as input without distinguishing sequence components, it is not suitable for asymmetric working condition simulation of systems with independent zero-sequence paths. Considering the representativeness of three winding transformers, this paper proposes an equivalent modeling method for unifying the symmetric and zero-sequence components. Firstly, the three-phase decoupling port voltage equation of the transformer was derived in detail. Then, based on the circuit topology and the flow characteristics of each sequence component, the non-critical nodes are eliminated, and the symmetric and zero-sequence components node voltage equations containing only six external nodes are obtained. We unify the equivalent models of symmetric and zero-sequence components by introducing a voltage component identification matrix. Finally, a test model is built based on a real-time simulation platform to verify the correctness of the proposed method under symmetric and asymmetric working conditions. The results show that the error of the model constructed by this method is within 0.1%, and the simulation time-step is less than 0.714 uF, which is better than the official model.

In order to test the travelling wave fault location devices that widely used in power system, a simulation model that can reflect the transformer characteristics of travelling waves on the transmission channel should be built. In this paper, the current transformer (CT) on the transmission channel is modelled, then the CT attenuation characteristic to travelling waves is proved by adding sine wave and square wave on the CT primary side. By using PSCAD and travelling wave fault locator examiner, a half-real time simulation environment is constituted to test the travelling wave fault locator. In PSCAD, CT is modeled by measuring parameters. Finally, amplitude frequency response characteristics of the actual CT and the CT model are compared. The result shows that simulation model in this paper reflects well on the CT high-frequency attenuation characteristic.

In a practical ±500 kV/3000 MW line commutated converter based high voltage DC (LCC-HVDC) transmission system, a sustained 5.5/105.5 Hz harmonic was observed in the voltage of the AC bus of inverter station. HVDC power limit function was triggered because of the action of AC filter resistance harmonic overload protection caused by the harmonic. To study the phenomenon, the real-time digital and physical closed-loop simulation platform based on real time digital simulator (RTDS) is first built and the harmonic instability phenomenon is reproduced. Then, its mechanism and impact factors are analyzed based on real-time simulation. Analyses results show that series resonance and core saturation are the main reasons of harmonic. AC/DC harmonic transfer characteristic through converter leads to the interaction of AC and DC network, and inappropriate AC/DC impedance results in the sustained harmonic. Bypassing the series capacitor is proposed as a temporary countermeasure and verified by on-site test. To solve the problem thoroughly, supplementary harmonic controller (SHDC) based on STATCOM is designed, whose validity is verified by simulation tests.

To guarantee an uninterruptable power supply, a microgrid must be able to operate in both islanded and grid-connected modes. Hence, it is required to synchronize the voltage phasor of the point of common coupling of the microgrid with the utility grid. Therefore, a distributed cooperative hierarchal control structure is proposed that seamlessly synchronized an islanded microgrid with the utility grid. A proposed method uses a leader-follower based consensus to regulate the voltage phasor while ensuring proportionate load sharing. A synchronization controller is designed that uses an adjustable parameter to eliminate the voltage magnitude and phase mismatch, and transmit the regulated compensation signal to the leader DGs. The leader DGs transmits these signals to the follower DGs through a cyber-channels. Moreover, a Massachusetts Institute of Technology rule and Lyapunov function based adaptive controllers are designed to update the secondary control law parameters in case of any disturbance or uncertainty. These adaptive techniques do not require prior knowledge about the microgrid topology, loads, and impedances thus enhancing the system performance. Furthermore, a small signal stability analysis is presented to facilitate the controller parameter design criteria. Finally, the robustness and effectiveness of proposed structure is verified through simulation results in different scenarios.

在实现"碳达峰、碳中和"目标、推动构建以新能源为主体的新型电力系统背景下,高比例新能源并网、高比例电力电子装备将成为未来新型电力系统的主要趋势和突出特征.文中首先概述了新型电力系统的特征,总结了新型电力系统对建模仿真技术提出的迫切需求,分别从建模优化方法、多时间尺度仿真方法和仿真计算加速方法等方面分析了电力系统建模仿真技术的现状和改进方案,同时,描述了面向新型电力系统的仿真新技术和应用新模式.最后,对建模仿真新技术及其应用新模式如何更好地适应新型电力系统构建和运行给出了建议.

Compared with the half controlled power electronic devices such as thyristor, the over-current ability of fully controlled power electronic devices such as insulated gate bipolar transistor (IGBT) is weak. In order to ensure that bridge arm current does not exceed the bearing range of modular multilevel converter (MMC) switching devices under AC fault ride through and other scenarios, MMC high voltage direct current (HVDC) system projects are equipped with temporary block (TB) function, IGBTs are protected by suspending the trigger pulse before bridge arm current reaches the maximum safe current of the switch. The structure of high side and low side valve group (VG) in series are adopted in ultra high voltage direct current (UHVDC) system. For line commuted converter (LCC) UHVDC system, the converter is current source type, During normal operation, there is no need to control the voltage balance between high side and low side VG, and after one VG is disturbed by commutation failure, the impact on another VG is relatively small. For MMC-UHVDC system, the converter is voltage source type, during normal operation, the voltage balance between high side and low side VG should be controlled. When a transient disturbance such as AC fault occurs, if one VG is temporary blocked due to bridge arm over-current, and another VG is not temporary blocked or the time of temporary blocked is later, the VG blocked first may tripped due to sub-module (SM) overall over-voltage or bridge arm over-current, and the scope of the accident is expanded, which is not conducive to the flexible and reliable operation of MMC-UHVDC. Therefore, the impact of non synchronous temporary block of MMC-UHVDC VGs is firstly analyzed in this paper, and then synchronous temporary block (STB) function between VGs is proposed, and the hardware interface scheme, STB signal sending and receiving logic, enable conditions and other aspects between VGs are elaborated. Finally, taking kunliulong project, the world’s first multi terminal Hybrid (MTH) UHVDC project, as the application background, a real-time simulation (RTS) test system for control and protection (C&P) system is established. The enable conditions of the STB function are verified. The response and dynamic characteristics of the system under abnormal measurement of bridge arm current, AC fault and VG short circuit fault when enabling or disabling STB function are compared. The simulation results show that the reliability of MMC-UHVDC can be improved by enabling STB function.

This paper introduces the basic situation of high frequency harmonic resonance in Guangxi on April 10, 2017, which is based on the Luxi back-to-back voltage source converter based high voltage direct current transmission (VSC-HVDC) project in China. Firstly, the harmonic amplification mechanism and its key links in the event are analyzed in detail and verified by simulation. Secondly, the relationship among high frequency harmonic resonance, voltage feedforward control loop and system harmonic impedance is obtained, and the formulas among voltage feedforward control parameters, system harmonic impedance and high frequency harmonic resonance frequency amplitude are deduced. Then, a method to suppress high frequency harmonic resonance by adding a reasonably filter to the voltage feedforward control loop is proposed. Finally, the effectiveness of the proposed method in this paper is verified by simulation and field operation.

The multi-terminal hybrid ultra-high voltage direct current (MTH-UHVDC) transmission technology combining line commuted converter ultra-high voltage direct current (LCC-UHVDC) technology and modular multilevel converter ultra-high voltage direct current (MMC-UHVDC), provides a more flexible and advanced mode to meet the needs of longer distance and larger capacity clean energy transmission. Compared with the two-end HVDC system, the control and protection (C&P) functional and dynamic characteristics of MTH-UHVDC transmission system are more complex. The real-time simulation technology must be used to carry out the experimental research before the engineering application. However, the hardware in loop (HIL) real-time simulation test of MTH-UHVDC transmission system is faced with many technical problems, such as multi-type interface of test system, accurate modeling of UHVDC MMC valve, full access of C&P devices, etc. Therefore, from the perspective of simulation test research and engineering application, this paper proposes a HIL real-time simulation test method for C&P system of MTH-UHVDC transmission system. The design of test system, accurate modeling of primary system, modeling of C&P system, interface technology of test system, functional and performance test method of C&P system and engineering application are deeply studied. Taking kunliulong project, the world's first MTH-UHVDC project, as the application background, a real-time simulation test system for C&P system is established by the proposed method. The functional performance test (FPT) and dynamic performance test (DPT) are carried out using the established test system, and the simulation test waveforms are compared with the field test waveforms. The results show that the response characteristics of the two systems are consistent, and the test system established in this paper can meet the needs of accurate real- time simulation test and research, and can provide technical support for the application of MTH-UHVDC technology.

当前电网正开展统一调频市场建设,在实际电网中开展自动发电控制(automatic generation control,AGC)功能测试的难度将进一步加大,调度自动化迫切需要有一个可真实模拟实际电网的仿真环境来支撑开展AGC功能测试.实时仿真在技术可行性上具备开展AGC闭环测试的能力,为验证其有效性,本文搭建了基于实时仿真的AGC闭环测试系统,反演了实际现场的AGC动作事件.试验结果表明建立的RTDS实时仿真模型具备仿真大电网系统频率变化的能力,同时RTDS系统具备与AGC应用闭环试验的能力,可应用于电网AGC功能测试工作.

广西-广东交流输电通道联络线(以下简称"两广断面")和近区电厂配置了大量失步解列装置,其可靠性对南方电网主网的安全稳定运行至关重要.基于实际一次系统构建了可精确定位振荡中心和计算测量点最小电压的等值系统模型,对多种型号和不同原理的失步解列装置开展了动态实时仿真校核,发现并解决了故障过程中失步闭锁判据不可靠、振荡中心落在失步安装点时装置拒动等典型问题,提高了失步判据和动作逻辑的可靠性;同时,基于电网全景仿真试验技术和实际系统失步解列配置,综合分析了两广断面近区失步解列装置协调配合存在的问题,提出了尽快将两广断面广域失步解列系统投入运行的实施建议.本文所提出的相关改进优化措施已在实际系统中得以应用.

传统的两端直流控制保护系统(简称"直流控保")与安全稳定控制系统(简称"稳控系统")的接口设计不能适用于多端混合直流工程.结合昆柳龙直流工程的应用实际,对多端混合直流控保和稳控系统的接口方式、数据传输和功能逻辑进行了重新设计,提出了一套直流控保和稳控系统接口时序配合和功率损失量计算的方法,实现方法简单,计算结果准确,能够大幅度简化稳控系统的相关计算逻辑.为了验证该接口设计的有效性,基于RT DS系统构建了实际直流控保和稳控系统组成的闭环实时仿真系统,对二者接口的关键技术细节和典型运行工况进行了详细仿真验证,提出了具体的优化改进措施.仿真研究结果表明该接口方案能够适应多端混合直流的复杂运行工况,应用该接口设计的昆柳龙直流工程已在现场投入运行.

直流输电送/受端(以下简称"直流近区")安全稳定控制(以下简称"稳控")系统的控制策略复杂,动作时序配合不当可能导致稳控装置不正确动作,后果严重.为此,基于直流近区稳控系统的实时仿真试验,从稳控系统主辅判据配合、装置采集量有效性辨识、多厂站多重故障动作时序等方面,选取故障过程中稳控装置不正确动作的相关案例进行分析,提出针对性的优化改进措施并进行仿真验证,总结形成稳控系统的软件设计原则.研究结果表明:在直流近区稳控系统的软件设计中,需考虑故障过程中参与策略计算的所有元件采集量和控制量的实时变化,选用合理的数据辨识方法或采用多重信息校验,综合考虑交直流控制系统的相互耦合作用,以有效提升稳控策略的可靠性.

为解决交流大扰动下电网换相换流器型高压直流(line commutated converter based HVDC,LCC-HVDC)输电系统等值计算模型中整流侧信息不易获取的问题,基于动态相量模型和准稳态模型,建立基于受端交流信息下LCC-HVDC的建模方法,针对受端换流器容易发生的换相失败问题,创建基于换相机理的开关函数的修改方法.故障仿真结果表明,该方法可以较为准确地反映受端交流扰动下的暂态响应特征,同时该方法还提高了计算速度,实现了仅基于受端交流信息下LCC-HVDC的高精度、实时化计算.