scholarly journals Parameter Optimization of Droop Controllers for Microgrids in Islanded Mode by the SQP Method with Gradient Sampling

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Peijie Li ◽  
Ziyi Yang ◽  
Shuchen Huang ◽  
Jun Zhang
Keyword(s):  
Optimization Problem ◽  
Heuristic Algorithms ◽  
Parameters Optimization ◽  
Stationary Points ◽  
Small Signal Stability ◽  
Signal Stability ◽  
Gradient Sampling ◽  
Nonsmooth Problem ◽  
Islanded Mode ◽  
The Stability

For enhancing the stability of the microgrid operation, this paper proposes an optimization model considering the small-signal stability constraint. Due to the nonsmooth property of the spectral abscissa function, the droop controller parameters’ optimization is a nonsmooth optimization problem. The Sequential Quadratic Programming with Gradient Sampling (SQP-GS) is implemented to optimize the droop controller parameters for solving the nonsmooth problem. The SQP-GS method can guarantee the solution of the optimization problem globally and efficiently converges to stationary points with probability of one. In the current iteration, the gradient of the nonsmooth function can be evaluated on a set of randomly generated nearby points by computing closed-form sensitivities. A test on the microgrid system shows that the optimality and the efficiency of the SQP-GS are better than those of the heuristic algorithms.

Analysis and Stability Enhancement of DG Sourced Power System with Modified AVR and PSS

2013 ◽  
Vol 768 ◽  
pp. 313-316
Author(s):  
P. Sivakumar ◽  
C. Birindha
Keyword(s):  
Power System ◽  
Distribution System ◽  
Transient Stability ◽  
Probabilistic Approach ◽  
Small Signal Stability ◽  
Signal Stability ◽  
The Stability ◽  
System Stabilizer ◽  
Stability Issues ◽  
Stability Enhancement

Distribution system is facing stability issues with integration of distributed generators and controllers. This proposed method presents the stability of renewable energy based distribution system with varying energy source considering intermittent nature of wind and solar energy using probabilistic approach. The system is supplied by conventional and distributed generating sources like PV and wind. Monte Carlo approach is used for predicting the wind and solar power uncertainties. Proposed work explains both small signal stability and transient stability enhancement of DG sourced power system with power system stabilizer and automatic voltage regulator .It is carried out in is 4 machine 10 bus system. The initial simulation has been carried out using MATLAB/SIMULINK.

scholarly journals Available Transfer Capability Calculation Constrained with Small-Signal Stability Based on Adaptive Gradient Sampling

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Peijie Li ◽  
Ling Zhu ◽  
Xiaoqing Bai ◽  
Hua Wei
Keyword(s):  
High Efficiency ◽  
Computing Time ◽  
Small Signal ◽  
Small Signal Stability ◽  
Available Transfer Capability ◽  
Sqp Method ◽  
Signal Stability ◽  
Gradient Sampling ◽  
Transfer Capability ◽  
Bus System

Due to the nonsmoothness of the small-signal stability constraint, calculating the available transfer capability (ATC) limited by small-signal stability rigorously through the nonlinear programming is quite difficult. To tackle this challenge, this paper proposes a sequential quadratic programming (SQP) method combined with gradient sampling (GS) in a dual formulation. The highlighted feature is the sample size of the gradient changes dynamically in every iteration, yielding an adaptive gradient sampling (AGS) process. Thus, the computing efficiency is greatly improved owing to the decrease and the parallelization of gradient evaluation, which dominates the computing time of the whole algorithm. Simulations on an IEEE 10-machine 39-bus system and an IEEE 54-machine 118-bus system prove the effectiveness and high efficiency of the proposed method.

Impedance Stability Criterion of Complex Connected DC Distributed Power System

2013 ◽  
Vol 321-324 ◽  
pp. 1449-1453 ◽  
Author(s):  
An Shou Li ◽  
Dong Lai Zhang ◽  
Qiang Tong
Keyword(s):  
Stability Problem ◽  
Mathematical Induction ◽  
Small Signal ◽  
Small Signal Stability ◽  
Loop Gain ◽  
Induction Method ◽  
Signal Stability ◽  
Nyquist Criterion ◽  
Distributed Power System ◽  
The Stability

The small-signal stability problem of complex connected DC DPS was studied. Using mathematical induction method, it is proved that the N subsystems cascaded DPS can be seemed as two equivalent subsystems at arbitrary interface as the stability conclusion is the same. But for complex connected DPS which have M sources, it could be equivalent to M sources and one load system instead of two equivalent subsystems and M minor loop gain at M different interfaces should be satisfied Nyquist criterion simultaneously to ensure the DPS's stability.

Research on Small Signal Stability of SVG DC Voltage close Loop Control

2011 ◽  
Vol 130-134 ◽  
pp. 2115-2119
Author(s):  
Cong Mei Zha ◽  
Yong Sheng Zhu ◽  
Qi Ying Xu
Keyword(s):  
System Stability ◽  
Equivalent Model ◽  
Small Signal ◽  
Small Signal Stability ◽  
Loop Control ◽  
Signal Stability ◽  
Instantaneous Power ◽  
Static Var Generator ◽  
The Stability ◽  
Close Loop Control

This paper makes analyses on the basic regulation characteristics of Static Var Generator (SVG). From the perspective of AC and DC’s instantaneous power balance, the approximate equivalent model of small signal perturbations method is established for analysing the system stability. The stability and dynamic characteristics research is performed accordingly, which provide a basis for parameters design of SVG.

scholarly journals An SQP Method Combined With Gradient Sampling for Small-Signal Stability Constrained OPF

2017 ◽  
Vol 32 (3) ◽  
pp. 2372-2381 ◽  
Author(s):  
Peijie Li ◽  
Junjian Qi ◽  
Jianhui Wang ◽  
Hua Wei ◽  
Xiaoqing Bai ◽  
...  
Keyword(s):  
Small Signal ◽  
Small Signal Stability ◽  
Sqp Method ◽  
Signal Stability ◽  
Gradient Sampling

Analyzing Small Signal Stability of Power System based on Online Data by Use of SMES

2009 ◽  
Vol 129 (11) ◽  
pp. 1290-1298
Author(s):  
Hiroyuki Ishikawa ◽  
Yasuyuki Shirai ◽  
Tanzo Nitta ◽  
Katsuhiko Shibata
Keyword(s):  
Power System ◽  
Small Signal ◽  
Small Signal Stability ◽  
Online Data ◽  
Signal Stability
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