A New Scheme for Damping Torsional Modes in a Series Compensated Power System
01 Jan 2009-
TL;DR: In this paper, a scheme for damping torsional modes in a series compensated power system has been developed, which utilizes the effectiveness of combined active power and frequency (C.A.P.F.) SVS auxiliary controller in co-ordination with an induction machine damping unit coupled to the T-G shaft.
Abstract: In the present paper, a new scheme for damping torsional modes in a series compensated power system has been developed. The proposed scheme, utilizes the effectiveness of combined active power and frequency (C.A.P.F.) SVS auxiliary controller in co-ordination with an induction machine damping unit coupled to the T-G shaft. Studies are conducted on the first IEEE benchmark model. The damping scheme stabilizes all the torsional modes over a wide operating range of power transfer. SVS is installed at the middle of transmission line to optimize the power transfer capability. Also the optimal location of IMDU along the T-G shaft has been determined by using eigenvalue analysis. It is found that locating IMDU after the IP turbine yields the maximum damping effect.
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01 Nov 2010
TL;DR: In this paper, series compensation in long transmission lines is an effective solution of enhancing power transfer capacity of Power System network in which series passive compensation and shunt active compensation provided by static synchronous compensator (STATCOM) and other FACTS controllers connected at the electrical center of the transmission line are considered.
Abstract: Series compensation in long transmission lines is an effective solution of enhancing power transfer capacity of Power System network In this paper, series passive compensation and shunt active compensation provided by static synchronous compensator (STATCOM) and other FACTS controllers connected at the electrical center of the transmission line are considered The presence of series capacitors has given rise to the phenomena Subsynchronous Resonance (SSR) But in few conditions such as in fault conditions, SSR phenomenon takes place which can damage the turbine generator shaft In this paper SSR phenomenon is studied with modified IEEE second benchmark model and various techniques has been developed for damping of SSR by adjusting the series compensation and using the FACTS controllers Results have been taken with the help of MATLAB simulation
8 citations
Cites background from "A New Scheme for Damping Torsional ..."
...Several studies have investigated the potential of using this capability in mitigating SSR of series capacitive compensated transmission grids [10] [11] [12] [13] [14] [15]....
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TL;DR: In this paper, a bus voltage and line current (BVLC) supplementary subsynchronous damping controller (SSDC) is proposed to alleviate the sub synchronous resonance (SSR) and damp power system oscillations in a power system.
Abstract: The sub synchronous resonance (SSR) is a substantial problem in power system having a steam turbine generator connected to a series compensated transmission system. Flexible AC transmission systems (FACTS) controllers are widely applied to mitigate SSR. In this paper, a bus voltage and line current (BVLC) supplementary subsynchronous damping controller (SSDC) is proposed to alleviate subsynchronous resonance (SSR) and damping power system oscillations in a power system. Both eigenvalue investigation and time-domain simulation results verify that the proposed method can damp torsional oscillations of the power system with SVS bus voltage and line current (BVLC) supplementary controller. The results demonstrate that the proposed controller has a successful performance in minimizing the SSR. It is shown that the controller is able to stabilize all unstable modes. The study is performed on the system adapted from the IEEE first benchmark model. All the simulations are carried out in MATLAB/SIMULINK environment.
3 citations
Cites background from "A New Scheme for Damping Torsional ..."
...Six Mass Spring Mechanical System (Typical SSR Studies) [18]...
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TL;DR: In this paper, a line current and active power (LCAP) supplementary subsynchronous damping controller (SSDC) is proposed to damp the sub-sychronous resonance caused by series capacitors.
Abstract: Subsynchronous Resonance (SSR) is a growing problem in power systems having series compensated transmission lines. Subsynchronous resonance with low frequency that surpasses aggregate fatigue threshold of the generator shaft frequently could significantly reduce the shaft service life, which is a new problem that emerges in recent years. Flexible AC transmission systems (FACTS) controllers are widely applied to alleviate subsynchronous resonance. A line current and active power (LCAP) supplementary subsynchronous damping controller (SSDC) is proposed to damp subsynchronous resonance caused by series capacitors. Both eigenvalue investigation and time-domain simulation results verify that the proposed control strategy can effectively damping power system oscillations of the power system with SVS and SSDC. Time domain simulations using the nonlinear system model are also carried out to demonstrate the effectiveness of the proposed damping controller. The recommended control approach has been accumulated with the IEEE first benchmark model for SSR study. The analysis indicates that SVS using the proposed control strategy has better alleviation effect and output characteristics. All the simulations are validated by using MATLAB/Simulink environment.
3 citations
Additional excerpts
...Six mass spring mechanical system (Typical SSR Studies) [18]...
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01 Feb 2016
TL;DR: In this article, a mitigation measure based on series capacitance compensation (SVC) is proposed to mitigate the SSR problem in transmission system, which occurs when a natural frequency of a series compensated transmission system coincides with the complement of one of the torsional modes of the turbine-generator shaft system.
Abstract: Due to development in the field of power system, more and more series capacitance compensations have been used in transmission system extensively and because of series capacitance compensation it leads to SSR problems. SSR occurs when a natural frequency of a series compensated transmission system coincides with the complement of one of the torsional modes of the turbine-generator shaft system. Under such circumstances, the turbine-generator shaft system oscillates at a frequency corresponding to the torsional mode frequency and unless corrective action is taken, the torsional oscillations can grow and may result in shaft damage in a few seconds. For mitigating the SSR in transmission system, a mitigation measure based on SVC is introduced[1].
3 citations
01 Jul 2016
TL;DR: In this article, three supplementary sub-synchronous damping controllers (SSDC) are proposed for damping out sub synchronous torsional oscillations in power system with capacitor compensated transmission line.
Abstract: In this paper three supplementary Sub-synchronous damping controllers (SSDC) are proposed for damping out sub-synchronous torsional oscillations in power system with capacitor compensated transmission line. Capacitor compensation has widely been used as a very valuable way of escalating the power transfer capability and improving stability of power systems. Capacitor compensation in long transmission lines may grounds sub-synchronous resonance (SSR). The eigenvalue investigation tool is used to ascertain the subsistence of SSR. An addition of supplementary controller is able to stabilize all unstable modes for T-network model. Eigenvalue investigation and time domain simulation are considered to investigate the performance of the controllers. The effectiveness of the proposed supplementary controller is compared on the IEEE first benchmark model for computer simulations of SSR by means of eigenvalue investigation in MATLAB/Simulink environment. Three supplementary sub-synchronous damping controllers are considered in order to compare effectiveness of SSDC during higher loading in alleviating the small signal stability problem.
2 citations
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References
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TL;DR: In this paper, an auxiliary subsynchronous damping controller (SSDC) is proposed to damp subsynchronic resonance (SSR) caused by series capacitors with the help of a static synchronous compensator (STATCOM).
Abstract: A long transmission line needs controllable series as well as shunt compensation for power flow control and voltage regulation. This can be achieved by suitable combination of passive elements and active FACTS controllers. In this paper, series passive compensation and shunt active compensation provided by a static synchronous compensator (STATCOM) connected at the electrical center of the transmission line are considered. It is possible to damp subsynchronous resonance (SSR) caused by series capacitors with the help of an auxiliary subsynchronous damping controller (SSDC) on STATCOM. The objective of this paper is to investigate the SSR characteristics of the system and propose a new design procedure for SSDC based on nonlinear optimization to meet the specifications on the damping torque in the range of critical torsional frequencies. The SSDC uses the Thevenin voltage signal to modulate the reactive current reference of STATCOM. The Thevenin voltage signal is derived from the locally available STATCOM bus voltage and reactive current signals. The STATCOM configurations considered in this paper are 12 pulse, two- and three-level voltage source converter with Type-2 and Type-1 control, respectively. The controller regulates either reactive current (supplied by the STATCOM) or the bus voltage. The 3-phase model of the STATCOM is based on switching functions. By neglecting harmonics in the switching function, D-Q model is derived which is combined with similar models of the other system components for linear analysis. The results of the linear analysis are validated by carrying out transient simulation based on the detailed nonlinear models. The study is performed on the system adapted from the IEEE First Benchmark Model.
211 citations
TL;DR: In this paper, the residue method was applied to linearized power system equations and obtained a generalized form which is suitable for different controller input/output channels and therefore suitable for control devices.
Abstract: The thyristor controlled series compensator (TCSC), a prominent FACTS device, can rapidly modulate the impedance of a transmission line, resulting in improvement of power system performance. The purpose of the work reported in this paper is to design a controller to damp interarea oscillations. The authors have applied the residue method to linearized power system equations and obtained a generalized form which is suitable for different controller input/output channels and therefore suitable for different control devices. This method, together with modal sensitivities, is applied to TCSCs to determine the location, feedback signal and controller design. The damping result is illustrated by comparing changes in damping ratio and identifying the increase of transfer capacity.
210 citations
"A New Scheme for Damping Torsional ..." refers background in this paper
...[8] showed the design of controller that can modulate the impedance of line for enhancing the damping of oscillations....
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TL;DR: In this paper, the use of damping torque technique to examine the efficacy of various control signals for reactive power modulation of a midpoint-located static VAr system (SVS) in enhancing the power transfer capability of long transmission lines is considered.
Abstract: The use of a damping torque technique to examine the efficacy of various control signals, for reactive power modulation of a midpoint-located static VAr system (SVS) in enhancing the power transfer capability of long transmission lines is considered. A new auxiliary signal, the computed internal frequency (CIF), is proposed which synthesizes the internal voltage frequency of the remote generator from electrical measurements at the SVS bus. It is demonstrated that this signal is far superior to other conventional auxiliary control signals in that it allows full utilization of the network transmission capacity. The damping torque results are correlated with those obtained from eigenvalue analysis. >
186 citations
"A New Scheme for Damping Torsional ..." refers methods in this paper
...In the mechanical model detailed shaft torque dynamics [10] has been considered for the analysis of torsional modes due to SSR....
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TL;DR: In this article, a control strategy for damping of electromechanical power oscillations using an energy function method is derived, and the effect of the damping effect is robust with respect to loading condition, fault location and network structure.
Abstract: This paper examines the enhancement of power system stability properties by use of thyristor controlled series capacitors (TCSCs) and static VAr systems (SVCs). Models suitable for incorporation in dynamic simulation programs used to study angle stability are analyzed. A control strategy for damping of electromechanical power oscillations using an energy function method is derived. Using this control strategy each device (TCSC and SVC) will contribute to the damping of power swings without deteriorating the effect of the other power oscillation damping (POD) devices. The damping effect is robust with respect to loading condition, fault location and network structure. Furthermore, the control inputs are based on local signals. The effectiveness of the controls are demonstrated for model power systems.
155 citations
TL;DR: In this article, a static synchronous series compensator (SSSC) is used to increase the network damping only at those frequencies that are critical for the turbine-generator shaft.
Abstract: In this paper, a novel control strategy for subsynchronous resonance (SSR) mitigation using a static synchronous series compensator (SSSC) will be presented. The SSSC is constituted by three single-phase voltage source converters. SSR mitigation is obtained by increasing the network damping only at those frequencies that are critical for the turbine-generator shaft. This is achieved by controlling the subsynchronous component of the grid current to zero. Using the IEEE First benchmark model, the effectiveness of the proposed control algorithm when mitigating SSR due to torsional interaction and torque amplification effect will be shown.
61 citations