Power Flow Compensation Research Articles

A control with differential power-flow compensating of microgrid under symmetrical fault conditions

The load side failure of an independent microgrid will lead to an imbalance in power supply and demand and voltage drop in the fault area. The use of traditional reactive power compensation to achieve fault traversal in microgrids cannot effectively solve. This article proposes a differential power flow compensation control strategy based on micro source feeder impedance. Utilize micro source redundant power to increase active power output and compensate for the required power flow in the fault area. Calculate the power flow compensation coefficient based on the difference in feeder impedance, and dynamically adjust the reference value of power flow compensation according to the required power in the fault area. By rationalizing the distribution of fault flow, the transient power balance and voltage support in the fault area can be improved. To a certain extent, it enhances the fault resilience of the independent microgrid, and improves the working reliability during fault traversal. At the same time, it reduces the sharp increase in line losses caused by fault currents, and even endangers the security of network structures. The effectiveness of the strategy was verified through simulation and experiments.

Optimal Integration of D-STATCOMs in Radial and Meshed Distribution Networks Using a MATLAB-GAMS Interface

This paper proposes an interconnection of the MATLAB and GAMS software interfaces, which were designed based on a master-slave methodology, to solve the mixed-integer nonlinear programming (MINLP) model problem associated with the problem regarding the optimal location and sizing of static distribution compensators (D-STATCOMs) in meshed and radial distribution networks, considering the problem of optimal reactive power flow compensation and the fact that the networks have commercial, industrial, and residential loads for a daily operation scenario. The objective of this study is to reduce the annual investment and operating costs associated with energy losses and the installation costs of D-STATCOMs. This objective function is based on the classical energy budget and the capacity constraints of the device. In the master stage, MATLAB software is used to program a discrete version of the sine-cosine algorithm (DSCA), which determines the locations where the D-STATCOMs will be installed. In the slave stage, using the BONMIN solver of the GAMS software and the known locations of the D-STATCOMs, the MINLP model representing the problem under study is solved to find the value of the objective function and the nominal power of the D-STATCOMs. To validate the effectiveness of the proposed master-slave optimizer, the 33-node IEEE test system with both radial and meshed topologies is used. With this test system, numerical comparisons were made with the exact solution of the MINLP model, using different solvers in the GAMS software, the genetic-convex strategy, and the discrete-continuous versions of the Chu and Beasley genetic algorithm and the salp swarm optimization algorithm. The numerical results show that DSCA-BONMIN achieves a global solution to the problem under study, making the proposed method an effective tool for decision-making in distribution companies.

Application of the SSA for Optimal Reactive Power Compensation in Radial and Meshed Distribution Using D-STATCOMs

This paper deals with the problem regarding the optimal placement and sizing of distribution static compensators (D-STATCOMs) in radial and meshed distribution networks. These grids consider industrial, residential, and commercial loads within a daily operation scenario. The optimal reactive power flow compensation problem is formulated through a mixed-integer nonlinear programming (MINLP) model. The objective function is associated with the minimization of the expected energy losses costs for a year of operation by considering the investment costs of D-STATCOMs. To solve the MINLP model, the application of a master–slave optimization approach is proposed, which combines the salp swarm algorithm (SSA) in the master stage and the matricial backward/forward power flow method in the slave stage. The master stage is entrusted with defining the optimal nodal location and sizes of the D-STATCOMs, while the slave stage deals with the power flow solution to determine the expected annual energy losses costs for each combination of nodes and sizes for the D-STATCOMs as provided by the SSA. To validate the effectiveness of the proposed master–slave optimizer, the IEEE 33-bus grid was selected as a test feeder. Numerical comparisons were made against the exact solution of the MINLP model with different solvers in the general algebraic modeling system (GAMS) software. All the simulations of the master–slave approach were implemented in the MATLAB programming environment (version 2021b). Numerical results showed that the SSA can provide multiple possible solutions for the studied problem, with small variations in the final objective function, which makes the proposed approach an efficient tool for decision-making in distribution companies.

Design of an Automated Dual IPCs 240 System for Asymmetric Power Flow Compensation in an AC Electric Network

In this paper, an automated dual IPCs 240 system for asymmetric power compensation, is designed from an analytical analysis of the power flow modes through the transmission line. Then, the ACL (automatic control logic) obtained consists of serial gates arrays of standard NAND/AND and OR operators. It has been implemented within Matlab/Simulink framework, and the simulation results obtained show the feasibility and great relevance of using the dual IPCs 240 technology, in power transmission networks under normal and contingency conditions.

MGWO-PI controller for enhanced power flow compensation using unified power quality conditioner in wind turbine squirrel cage induction generator

Power quality is considered to be the major challenging one in the realization of the smart grid. So as to compensate for the issues occurring in power quality, active power filter (APFs) is mainly chosen as they are capable of filtering fast and has some active compensation. Also, load current related power quality constraint can be solved, such as unbalanced power, huge (Total harmonic distortion) THD level, and reduced power factor. For correcting the inappropriate supply of voltage and load current, the unified power quality conditioner (UPQC) and an effective integration of wind turbine are employed. A UPQC is a group of both shunt and series APF in a continuous manner having a conventional DC link capacitor. The voltage control of the DC link capacitor is significant in attaining a preferred performance on UPQC. In this paper, the UPQC with a Modified Grey Wolf Optimization (MGWO) based PI controller integrated with renewable energy like Wind turbine squirrel cage induction generator (SCIG) was implemented for the elimination of voltage and current harmonics imperfection precisely. Likewise, the Modified Grey Wolf Optimization (MGWO) was also exploited in UPQC. The performance analysis was made with UPQC, without UPQC, and with MGWO & UPQC and the simulation, outcomes are estimated and compared for the parameters THD values, load voltage and current. Also, the performance analysis was implemented in hardware prototype set-up and the results attained are depicted.

Control of a Modular Multilevel Matrix Converter for Unified Power Flow Controller Applications

The modular multilevel matrix converter has been proposed as a suitable option for high power applications such as flexible AC transmission systems. Among flexible AC transmission systems, the unified power flow controller stands out as the most versatile device. However, the application of the modular multilevel matrix converter has not been thoroughly analyzed for unified power flow controller applications due to the sophisticated control systems that are needed when its ports operate at equal frequencies. In this context, this paper presents a cascaded control structure for a modular multilevel matrix converter based unified power flow controller. The control is implemented in a decoupled reference frame, and it features proportional-integral external controllers and internal proportional multi-resonant controllers. Additionally, the input port of the modular multilevel matrix converter is regulated in grid-feeding mode, and the output port is regulated in grid-forming mode to provide power flow compensation. The effectiveness of the proposed vector control system is demonstrated through simulation studies and experimental validation tests conducted with a 27-cell 5 kW prototype.

電圧不安定を含む(N-1)電圧安定性高速ランキング手法

In this paper, the fast voltage stability contingency ranking method including unstable contingency cases is proposed. The proposed method provides the following three advantages at once: i) Reduction of the computation time for voltage stability contingencies using the concept of the power flow compensation, ii) Calculation of the voltage stability index for all load buses and assessment of the voltage stability for each N-1 contingency, iii) Estimation of the necessary amount of load shedding ΔPcut on condition that stabilizing the unstable load buses is required. The proposed method makes it possible to arrange contingency cases in descending order according to the severity of voltage stability index and the amount of load shedding, although unstable load buses are included in contingency cases. The performance of the method is validated using simple a 6-node test system and a modified IEEE 30 bus system.