Thyristor-based damping of turbine-generator shaft torsional oscillations resulting from power system disturbances and subsynchronous resonance-a review

2002 ◽  
Author(s):  
M.H. Nehrir ◽  
M.K. Donnelly ◽  
R. Adapa
Keyword(s):  
Power System ◽  
Turbine Generator ◽  
Torsional Oscillations ◽  
Subsynchronous Resonance ◽  
Power System Disturbances

Damping Subsynchronous Resonance Using a Static Synchronous Series Compensator Based Supplementary Damping Controller

2019 ◽  
Vol 42 ◽  
pp. 122-138
Author(s):  
Mahlomola Masenkane ◽  
Rudiren Pillay Carpanen
Keyword(s):  
Power System ◽  
Computer Aided Design ◽  
Turbine Generator ◽  
Torsional Oscillations ◽  
Subsynchronous Resonance ◽  
Detailed Simulation ◽  
Single Machine Infinite Bus ◽  
Aided Design ◽  
Static Synchronous Series Compensator ◽  
Damping Controller

This paper investigates the effectiveness of a supplementary damping controller around a Static Synchronous Series Compensator (SSSC) in mitigating the torsional oscillations due to interaction of series compensated transmission line with the nearby turbine-generator shafts. The main objective of the controller is to suppress the unstable torsional oscillations with frequencies coinciding with the turbine-generator shaft torsional modes, through modulation of the reactance provided by the SSSC. Detailed simulation studies are done in Power System Computer Aided Design (PSCAD) using a single machine infinite bus (SMIB) power system adopted from the IEEE first benchmark model (FBM) for subsynchronous resonance analysis. The results show that this supplementary damping controller can provide positive damping to the unstable torsional oscillations due to presence of conventional series capacitors in the line or an SSSC or a combination of both the SSSC and conventional series capacitor banks.

Subsynchronous Resonance and Torsional Effects on a Steam Turbine Generator in Transmission Systems With Series Capacitor Compensation

2012 ◽  
Author(s):  
K. R. Mutama ◽  
J. Seeliger ◽  
D. H. Baker ◽  
R. D’Aquila ◽  
B. Fitzgerald ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Operating Conditions ◽  
Torsional Stress ◽  
Turbine Generator ◽  
Transmission Systems ◽  
Torsional Oscillations ◽  
Subsynchronous Resonance ◽  
Modeling Studies ◽  
Series Capacitor ◽  
Series Capacitors

Turbine-generators which connect to transmission systems with series capacitor compensated lines can experience problems with the torsional oscillations of the shaft interacting with the electrical oscillations of the series capacitors and transmission system inductance. This resonant interaction is called Subsynchronous Resonance (SSR) since it involves torsional and electrical oscillations which are below the synchronous operating frequency of the power system. The transmission lines near the Newmont TS Power Plant will soon have series capacitors installed. Modeling studies based on calculated torsional frequencies and estimated torsional damping showed that the turbine-generator could have instabilities of the torsional oscillations under some operating conditions. After the modeling studies were completed, actual tests on the steam turbine generator were conducted to measure the frequency and mechanical damping of the torsional oscillations. Field measurements validated modeling studies and showed the SSR risk may be higher than originally estimated. As a result of these investigations, a torsional stress relay is being installed to protect the unit from subsynchronous torsional effects of the series capacitors. The torsional stress relay will trip the unit if damaging torsional oscillations or torsional instabilities occur.

scholarly journals Subsynchronous Resonance and FACTS-Novel Control Strategy for Its Mitigation

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Doan Duc Tung ◽  
Le Van Dai ◽  
Le Cao Quyen
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Control Strategy ◽  
Power Plants ◽  
Thermal Power ◽  
Transmission System ◽  
Static Synchronous Compensator ◽  
Turbine Generator ◽  
Subsynchronous Resonance ◽  
Ac Transmission

The subsynchronous resonance (SSR) is an important problem in the power system, and especially the series compensated transmission lines may cause SSR in the turbine generators, such that it leads to the electrical instability at subsynchronous frequencies and potential turbine-generator shaft failures. Taking the Vietnamese Vungang thermal plants as an example, a shaft failure of Vungang I thermal power unit has occurred on November 24, 2015, due to SSR. The main cause for this failure is a resonance caused by the series capacitors on the 500 kV grid. This paper analyzes the SSR based on the location of shaft cracks and turbine generator mode shape for Vungang I and II thermal power plants. On the basis of that, it develops a novel control strategy for each Flexible AC Transmission system (FACTS) device as the thyristor controlled series compensator (TCSC), static VAR compensator (SVC), and static synchronous compensator (STATCOM). Then they are comparable to one another in order to choose a feasible solution for mitigating the SSR. The effectiveness of the proposed control strategy is verified via time domain simulation of the Vietnamese 500/220 kV transmission system using EMTP-RV and PSS/E programs. The obtained results show that the proposed strategy for SVC can be applied to immediately solve the difficulties encountering in the Vietnamese power system.

Fuzzy-Based Torsional Oscillations Mitigation via Thyristor Switched Braking Resistor in Multi-Machine Power System

2020 ◽  
Vol 12 (8) ◽  
pp. 1102-1124
Author(s):  
M. Fayez ◽  
F. Bendary ◽  
M. El-Hadidy ◽  
M. Mandor
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
High Speed ◽  
Transient Stability ◽  
Fuzzy Logic Controller ◽  
Low Cost ◽  
Torsional Oscillation ◽  
Turbine Generator ◽  
Torsional Oscillations ◽  
Interconnected Power System

Turbine generator shaft torsional oscillations is an interdisciplinary power system dynamic problem as it involves mechanical and electrical engineering. Torsional oscillations occur in the mechanical for electrical reasons. Torsional oscillations cause fatigue life expenditure of the mechanical shaft system. There have been great motivations to mitigate the shaft torsional oscillations especially when unrestricted high speed reclosure (HSR) is utilized on the overhead transmission lines emanating from a generation station. Mitigation of torsional oscillation compromises between the use of HSR and preserving the mechanical integrity of the involved turbine generator set. Therefore, braking resistor (BR) controlled by fuzzy logic controller is presented in this paper as a low cost, reliable mean for torsional oscillations mitigation. BR was first utilized for the system transient stability enhancement. It serves as an extra load capable of dissipating extra generated power in case of system severe faults close to a generation station consequently prevents generator pole slipping conditions. IEEE 3 machine 9 bus system is adopted in this paper to test the effects of BR on shaft torsional oscillations mitigation in interconnected power system. Comparative simulation studies between the unsuccessful reclosure with and without fuzzy controlled BR prove the effectiveness of the scheme for mitigation of torsional oscillations significantly.

Controlling Chaos and Bifurcation of Subsynchronous Resonance in Power System

2002 ◽  
Vol 7 (2) ◽  
pp. 15-36 ◽  
Author(s):  
A. M. Harb ◽  
M. S. Widyan
Keyword(s):  
Power System ◽  
Nonlinear Controller ◽  
Feedback Controllers ◽  
Turbine Generator ◽  
Subsynchronous Resonance ◽  
Narrow Region ◽  
Series Resonant ◽  
Disturbance Response ◽  
System Stabilizer ◽  
Damper Windings

Linear and nonlinear state feedback controllers are proposed to control the bifurcation of a new phenomenon in power system, this phenomenon of electro-mechanical interaction between the series resonant circuits and torsional mechanical frequencies of the turbine generator sections, which known as Subsynchronous Resonance (SSR). The first system of the IEEE second benchmark model is considered. The dynamics of the two axes damper windings, Automatic Voltage Regulator (AVR) and Power System Stabilizer (PSS) are included. The linear controller gives better initial disturbance response than that of the nonlinear, but in a small narrow region of compensation factors. The nonlinear controller not only can be easily implemented, but also it stabilizes the operating point for all values of the bifurcation parameter.

scholarly journals Torsional Oscillations Mitigation via Interval Type-2 Fuzzy Logic Brake Control

2020 ◽  
Vol 19 (2) ◽  
pp. 16-21
Author(s):  
Mohamed Fayez ◽  
Fahmy Metwally Bendary ◽  
Mohamed El-Hadidy ◽  
Mohamed Adel Mandor
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Fuzzy Logic Controller ◽  
Power Grids ◽  
Turbine Generator ◽  
Torsional Oscillations ◽  
Single Machine Infinite Bus ◽  
Interval Type ◽  
Dynamic Braking

Turbine-generator shaft torsional oscillations is an interdisciplinary power system dynamic problem because it encompasses mechanical and electrical sectors of power grids. They give rise to a premature expenditure of fatigue life of the turbine-generator shaft metal which could lead to shaft cracks. This paper introduces an interval type-2 fuzzy logic controller to regularize the dynamic braking interventions of a novel braking resistor model for mitigation of torsional oscillations resulting from unsuccessful autoreclosure procedures near generation stations. The effectiveness of proposed scheme is elucidated by considering the unsuccessful autoreclosure of three-phase-to-ground fault in a single machine infinite bus power system via MATLAB/Simulink-based modeling and simulation environment with the help of interval type-2 fuzzy logic controller toolbox. The comparative simulation results with and without the suggested mitigation regime show that the proposed scheme is effective in the mitigation of torsional torque oscillations

Sign in / Sign up

Export Citation Format

Share Document