Coordinated control of TCPS and SMES for frequency regulation of interconnected restructured power systems with dynamic participation from DFIG based wind farm

Among the several wind generation technologies, variable-speed wind turbines utilizing doubly fed induction generators (DFIG) are gaining momentum in the power industry. Increased penetration of these wind turbine generators displaces conventional synchronous generators which results in erosion of system frequency. With this assertion, the paper analyzes the dynamic participation of DFIG for frequency control of an interconnected two-area power system in restructured competitive electricity market. Frequency control support function responding proportionally to frequency deviation is proposed to take out the kinetic energy of wind turbine for improving the frequency response of the system. Impacts of varying wind penetration in the system and varying active power support from DFIG on frequency control have been investigated. The presence of thyristor controlled phase shifter (TCPS) in series with the tie-line and Superconducting Magnetic Energy Storage (SMES) at the terminal of one area in conjunction with dynamic active power support from DFIG results in optimal transient performance for PoolCo transactions. Integral gains of AGC loop and parameters of TCPS and SMES are optimized through craziness-based particle swarm optimization (CRPSO) in order to have optimal transient responses of area frequencies, tie-line power deviation and DFIG parameters.     

FACTS装设地点的定量评估及优化

利用EEAC对电力系统暂态稳定性严格量化的能力,可以精确地评估各种连续或离散的变化对 稳定程度的影响。如果要快速地评估FACTS对暂态稳定性的影响,优化其装设地点,则还可 以简单地用稳定裕度对FACTS设备主回路参数的灵敏度系数来量化紧急控制效果。取可控串 联补偿和可控移相器为例,通过对华中网的数值仿真验证了上述方法的有效性。     

双芯对称离散型可控移相器对纵联保护的影响分析

晶闸管控制的移相器(Thyristor Controlled Phase Shifter,TCPS)通过调整移相角实现电网潮流分布的控制,可有效改善电网潮流分布,提高电网运行经济性。但移相器的应用改变了电网结构和相间耦合关系,当常规纵联保护直接应用于含有移相器的线路时,需考虑移相因素对差动电流的影响以及采用合适的差动电流计算方法,同时需考虑互感器的安装位置的选取,而纵联方向保护方向元件是否受影响也需要做进一步的分析。针对安装了TCPS的输电线路纵联保护进行了分析和仿真研究,建立了相应的电磁仿真模型,在此基础上分析了互感器安装于不同位置时,常规方向元件、差动元件的动作特性,并提出了几种可能的差动电流计算方法,仿真分析了纵联保护在含移相器线路的适应性。研究表明,移相器的接入对于纵联方向保护的方向元件没有影响,但对常规电流差动保护影响较大,纵联保护应用中宜使用线路侧互感器实现。     

含FACTS元件的电力系统潮流计算

采用灵活交流输电系统（ＦＡＣＴＳ）技术可以实现对系统潮流分布的直接灵活控制，充分发挥现有输电系统的潜力。本文着重研究用于系统潮流控制的ＦＡＣＴＳ元件的潮流计算数学模型及其潮流控制的模拟方法，并开发出一个通用的ＦＡＣＴＳ系统潮流计算软件包，给出了计算实例。     

Performance enhancement of a hydro-hydro power system using RFB and TCPS

The design of load frequency control (LFC) for the hydro-hydro power system suffers from poor dynamic performance owing to large time constants associated with hydro power generations. The dynamic performance of the hydro-hydro power system can be improved using a thyristor control phase shifter (TCPS) and energy storage battery system. This paper presents a comprehensive study on LFC of an interconnected hydro-hydro power system having TCPS in series with the tie-line and redox flow battery (RBF) at the terminal of one area through few and available state technique, i.e. the output feedback technique. The LFC are designed with the help of few and available states and the performance is judged for typical demand change in the power system area and the results are matched with the LFC obtained via a technique that require all system states, i.e. full state feedback in order to justify the effectiveness of the designed LFC in terms of achieved feedback gains, eigenvalues and the dynamic system responses.

Abbreviations: AC: Alternating Current; BESS: Battery Energy Storage System; FACTS: Flexible Alternating Current Transmission System; LFC: Load Frequency Control; RFB: Redox Flow Battery; SSSC: Static Synchronous Series Compensator; SMES: Superconducting Magnetic Energy Storage; TCPS: Thyristor Control Phase Shifter; UPFC: Unified Power Flow Control     

柔性交流输电系统潮流计算中改进的遗传算法

阐述了一种在具有柔性交流输电装置的电力系统中求解最潮流问题的改进的遗传算法对两种柔性交流输电装置进行了研究,用于潮流控制的晶闸管控制相器和晶闸管控制的串顺在求解过程中结合最佳交流潮流,用遗传算法通过选择最佳调节状态使总发电成本最低,且使潮流保持在安全极限内,。用ＩＥＥＥ１４节点系统进行了测试,证实了其可行性和有效性。     

Employing TCPS for suppressing oscillations in two‐area system constitute of wind farm and thermal system

The use of distributed generation (DG) is growing. However, DG may never be an alternative for major power generation, but they can be used in a combined form with other production units in the network. Among renewable energies, wind power especially when the case is a wind farm has a great power and capability. On the other hand, to generate electricity with desired quality and reliability, having proper dynamic response of wind farm and major network seems necessary. By employing thyristor‐controlled phase shifter (TCPS) in series with the tie‐line between two systems composed of wind farm and thermal system, the dynamic response of the combined system is improved. Results show that in all situations TCPS is able to suppress frequency deviation and tie‐power oscillations effectively under the occurrence of sudden load changes in any of the areas when compared with that obtained without TCPS. Furthermore, the required time to reach steady‐state in any of the areas is decreased dramatically. Also, for tie‐power variations in addition to reduction of oscillations, overshoot is decreased remarkably several times more than the case that system in not equipped with TCPS. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

ALFC of hybrid multi-generation power system using UC and TCPS by ANFIS control technique

ABSTRACT

This paper reveals the impact of an ultra-capacitor (UC) and thyristor control phase shifter (TCPS) on frequency stability of large hybrid interconnected power system. The impact of UC and TCPS has been studied for general purpose hybrid generated multi areas power system. Further to this, an adaptive neuro fuzzy inference system (ANFIS) is is proposed for automatic load frequency control (ALFC). Thermal and reheat thermal plants are connected in Area-1 and area-2, whereas area-3 has hydro plant and area-4, 5, 6 consists of nuclear power plant, diesel power and gas turbine plant, respectively. A micro grid based on Solar Photovoltaic (PV) system and fleet of electric vehicle (EV) system is developed and integrated with load side of area-1 for load management in interconnected grid. Effect of Small load change and large load change are discussed in separate cases. The controllers are tuned by adding sliding surface to enhance the performance. A comparison between ANFIS and PI-based control approaches with and without UC and TCPS exhibits the superiority of ANFIS controller by integrating UC and TCPS. The results of the proposed control technique are compared with already published results.     

Comparative performance evaluation of SMES-SMES, TCPS-SMES and SSSC-SMES controllers in automatic generation control for a two-area hydro-hydro system

This paper presents the automatic generation control (AGC) of an interconnected two-area multiple-unit hydro-hydro system. As an interconnected power system is subjected to load disturbances with changing frequency in the vicinity of the inter-area oscillation mode, system frequency may be severely disturbed and oscillating. To compensate for such load disturbances and stabilize the area frequency oscillations, the dynamic power flow control of static synchronous series compensator (SSSC) or Thyristor Controlled Phase Shifters (TCPS) in coordination with superconducting magnetic energy storage (SMES) are proposed. SMES-SMES coordination is also studied for the same. The effectiveness of proposed frequency controllers are guaranteed by analyzing the transient performance of the system with varying load patterns, different system parameters and in the event of temporary/permanent tie-line outage. Gains of the integral controllers and parameters of SSSC, TCPS and SMES are optimized with an improved version of particle swarm optimization, called as craziness-based particle swarm optimization (CRPSO) developed by the authors. The performance of CRPSO is compared to that of real coded genetic algorithm (RGA) to establish its optimization superiority.