Use Of Series Compensator Research Articles

Предел передаваемой мощности управляемой линии электропередачи высокого напряжения для режимов на границе статической устойчивости

The use of series compensation devices is one of the methods to increase the capacity of a power transmission line. In addition, the use of controlled series compensation devices affects the steady-state stability of the electric power system. It is also widely known that automatic excitation control of generators has a positive effect on the stability of the system. Thus, it is reasonable to analyze the influence of the adjustable parameters of the controlled series compensation device on the line capacity when considering modes at the boundaries of the stability regions, taking into account automatic excitation controllers on synchronous generators of the power plant. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C ++ programming language is used as a modeling tool. The authors have selected the regulation laws parameters of controlled series compensation device and automatic excitation controller, provided that steady-state stability is maintained. The stability regions of the electric power-engineering system under study are constructed depending on the tuning parameters of the considered devices. A technique is proposed to select the coefficients of complex regulation of the devices to increase the capacity of a high-voltage power transmission line. The proposed method of the complex selection of regulation coefficients of controlled devices provides the possibility of obtaining their optimal values in a controlled electric power system to ensure stability.

Energy-Shaping Controller for DFIG-Based Wind Farm to Mitigate Subsynchronous Control Interaction

Increasing use of series compensation in doubly-fed induction generator (DFIG)-based wind farms has led to subsynchronous control interaction (SSCI) incidents. The irregular exchange of energy between the network side and generator side is considered responsible for SSCI. Therefore, an energy-shaping controller (ESC) is proposed in this paper to mitigate SSCI from the energy perspective. Firstly, based on energy relationship and physical nature, Hamiltonian model is established to describe the system structure. Secondly, the controller is obtained by solving the energy equation. Damping is then injected into the controller dynamics and it is back-propagated to the system, ensuring the global asymptotical stability. Thirdly, the controller is further improved to make gamma-dissipation inequality hold, thereby enhancing the robustness. Time-domain simulation and impedance model (IM)-based stability analysis are conducted to evaluate the damping performance of ESC. Simulation results demonstrate the effectiveness of ESC under a wide range of operating conditions. Moreover, ESC also improves system robustness against external disturbance and parameter uncertainty.

Safe Sub Synchronous Oscillations Response for Large DFIG-Based Wind Farms

This paper presented an accurate analysis of the instability in DFIG-based wind farms due to the use of series compensation and provided maximum power extraction from these farms using the high compensation without the unstable sub-synchronous oscillation occurrence. For this purpose, using modal analysis, it is first shown that the main cause of this instability is low wind speed in the high compensation. This issue causes the series compensated DFIG-based wind farms is unstable due to a sub-synchronous mode. In order to prevent the unstable sub-synchronous oscillation occurrence, a supplementary controller called SSRIPC and DFIG controllers are used. Also, for good dynamic response and proper use of the SSRIPC, an objective function considered based on three factors of minimum damping ratio, overshoot, and settling time of the oscillations. By accurate optimization of the proposed controller using root-locus and PSO algorithm, it is prevented the instability caused by sub-synchronous resonance and sub-synchronous control interaction that are classes of the sub-synchronous oscillations. IEEE SSR first benchmark model and MATLAB/Simulink software are used to validate the performance of the proposed method.

Damping of subsynchronous resonance using a voltage source converter‐based high‐voltage direct‐current link in a series‐compensated Great Britain transmission network

Owing to increased levels of generation in Scotland, substantial onshore and offshore reinforcements to the Great Britain (GB) transmission network have been proposed. Possible inland reinforcements include the use of series compensation through fixed capacitors. This potentially can lead to subsynchronous resonance (SSR). Offshore reinforcements are proposed by high-voltage direct-current (HVDC) links. In addition to its primary functions of bulk power transmission, a voltage source converter-based HVDC link can be used to provide damping against SSR, and this function has been modelled. Simulation results have been carried out in Power Systems Computer-Aided Design, with system analysis conducted in MATLAB. A real-time hardware-in-the-loop real-time digital simulator-HVDC test rig has been used to implement and validate the proposed damping scheme on an experimental platform. The simulation and experimental results show good agreement.

Transient Performance of Series-Compensated Three-Phase Self-Excited Induction Generator Feeding Dynamic Loads

This paper presents the transient performance of a series-compensated three-phase self-excited induction generator (SEIG) feeding a dynamic load such as a three-phase squirrel-cage induction motor (IM). Mathematical modeling and simulation study of SEIG and an induction motor (SEIG-IM) combination is carried out using MATLAB/Simulink. An exhaustive experimental study is conducted using a Mawdsley's generalized machine operating as a SEIG and a three-phase squirrel-cage IM as the dynamic load. The simulated results are compared with the experimental results under various operating conditions of the SEIG such as the following: 1) its voltage and current buildup at no-load; 2) switching of a three-phase squirrel-cage IM to the SEIG terminals without series-compensating capacitors (resulting failure to start an IM); and 3) switching on the same motor with the series capacitors (resulting in successful starting of the IM). A sudden switching of the IM as a dynamic load on the SEIG without the series compensation causes severe transients in electrical and mechanical variables of the SEIG and due to large starting current requirement of the IM, there is a collapse of the terminal voltage of SEIG. However, the use of series compensation in short-shunt configuration of SEIG results in the successful starting of the IM with an improved voltage regulation of SEIG. The phenomenon of subsynchronous resonance (SSR) is observed due to the large variations in the impedance of the SEIG-IM combination and the presence of series capacitors. It causes low frequency oscillations in the IM stator voltages, currents, and its speed. The SSR phenomenon restricts the IM to attain the rated speed. A detailed study of the SEIG-IM system is made to select proper combination of shunt and series capacitors to avoid the SSR phenomenon.

A New Scheie for Subsynchronous Resonance Damping of Torsional Oscillations and Transient Torque - Part I

Series capacitor compensation of long and medium lines offers convincing advantages of optimum use of transmission lines. Technical problems with series capacitor protection and, more recently, the problems of subsynchronous resonance, resulting in high stresses on the turbogenerator shafts, have been a deterrent to widespread use of series compensation. Some generally complementary solutions to these problems have emerged, but further advances are needed.

Characteristics of a 400-mile 230-kv series-capacitor-compensated transmission system

SERIES capacitors have been recognized for some time as a means of increasing the amount of power transmitted over a long transmission line and as a means of increasing the distance that alternating-current power can be transmitted economically. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> The basic concept of neutralizing any portion of the series inductive reactance of a long transmission system by means of series capacitors is theoretically sound. The practical application of series capacitors for such service introduces several new and interesting problems of system design and operation, which while capable of solution will require the attention of engineers of both the equipment manufacturers and the operating companies. It is the objective of this paper to outline system characteristics encountered when series-capacitor compensation is used, with a view toward solving the problems arising therefrom. No attempt will be made to reexamine the relative cost of transmission with and without series compensation. In fact, the cost of the compensated system will be influenced to a certain degree by the methods used to solve the problems arising through use of series compensation.