Improvement of Small Signal Stability of SMIB System with Optimized Power System Stabilizer

As electrical power system is a complex system, there are more chances of stability issues may arise. One of the stability issues is Low Frequency Oscillations (LFOs) which makes the system unstable. As these oscillations are having low frequency i.e. large time constant with slowly increasing magnitude, they are referred to small signal stability. The main reason of these oscillations is due to lack of sufficient damping torque. Automatic Voltage Regulator (AVR) action in generator is providing sufficient synchronizing torque for system stability. This is possible with high gain and low time constant AVR which results in reduction of damping torque. Power System Stabilizer (PSS) is used together with AVR for providing necessary damping torque to minimize the LFOs. For effective damping, the PSS performance is improved by optimizing its parameters. In this paper, Single Machine Infinite Bus (SMIB) system is considered for studying the effect of LFOs. The SMIB system is simulated for a step disturbance in reference voltage and the results are carried out for different optimizing techniques Particle Swarm Optimization (PSO), Cat Swarm Optimization (CSO), Teaching and Learning based Optimization (TLBO)

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Enhancement of Small Signal Stability of SMIB System with Robust Power System Stabilizer

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1575.0982s1119 ◽

2019 ◽

Vol 8 (2S11) ◽

pp. 3416-3423

Keyword(s):

Power System ◽

Low Frequency ◽

Synchronous Machine ◽

Power System Stabilizer ◽

Local Mode ◽

Small Signal ◽

Small Signal Stability ◽

Signal Stability ◽

Low Frequency Oscillations ◽

System Stabilizer

As power system experiences low frequency oscillations due to disturbances, these low frequency oscillations are related to the small signal stability of a power system. The phenomenon of stability of synchronous machine under small perturbations is explored by examining the case of an SMIB system. The analysis of SMIB gives physical insight into the problem of low frequency oscillations. The SMIB system is predominant in local mode low frequency oscillations. These oscillations may sustain and grow to cause system separation if no adequate damping is available. The damping is provided by adding Power System Stabilizer for Synchronous Machine. In addition, as power system is nonlinear in nature, application of robust control techniques is mandatory to face the challenge of dynamic conditions. Hence, this work aims to design robust Power System Stabilizer for Synchronous Machine in order to damp the rotor speed deviations.

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Improved DE Algorithm for Power System Stabilizer for Damping Low Frequency Osci llations

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.b1091.1292s219 ◽

2019 ◽

Vol 9 (2S2) ◽

pp. 606-611

Keyword(s):

Power System ◽

Low Frequency ◽

Operating Conditions ◽

Power System Stabilizer ◽

Small Signal ◽

Small Signal Stability ◽

Interconnected Power System ◽

Signal Stability ◽

De Algorithm ◽

System Stabilizer

In the large interconnected power system, maintaining the Small signal stability of the system is of more concern, for the stable, secure and reliable operation. This paper proposes an Improved Differential Evolution (DE) Algorithm based Optimal Power system stabilizer (PSS) for damping the low frequency oscillations. Enhancing the damping of system is formulated as the optimization problem. DE/Best Mutation Operator is adopted for producing the mutation vector, to augment the convergence rate of DE algorithm. The effectiveness of the proposed approach has been tested in Single Machine Infinite Bus (SMIB) system under different operating conditions. The time response evaluations has justified the superiority of the proposed approach for damping the oscillations and thereby improving the Small signal stability of the system.

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