Reactive Power Flow In Line Research Articles

Load Flow Calculation For Electrical Power System Based On Run Length Encoding Algorithm

This paper presents Data Compression Simulated algorithm for load flow calculation in electrical power systems. Real time monitor of grids required less computation time in calculation of power system analysis. Load flow problem is heart of this analysis and it basically required calculate active and reactive power flow in lines connected between buses in networks. Many topology and structures for Transmission and Distribution Systems has been proposed to reduce CPU times and memory. The proposed algorithm used Data compression technique tested different systems and results shows it is efficiency. More accuracy for large systems will need more iterations calculation which mean increasing time consumption, while Run Length Encoding (RLE) algorithm is fitness to optimized calculation numbers to exact number cause it has no zero values included. Network structure was represented as one dimension vector instead of 2D Matrix and it is effectiveness results was valid, by avoid exponential increased, by utilized this algorithm. Matlab results obtained by applied this algorithm match theoretical results.

Attaining Higher Reliability in Power Systems by Using Facts

Overload in transmission systems and higher demand of electric energy have necessitated higher production of electric energy. However, it is very difficult to obtain new limits for transmission lines. Therefore, power generation and transmission companies try to make use of maximum capacity of their transmission lines. As a novel technology, FACTS have enabled companies to generate higher energy along with attaining high level system reliability. FACTS is composed of several components, e.g. TCSC, UPFC, and SVC. TCSC is a capacitor reactance compensator including a capacitor bank in series which is paralleled with a thyristor-controlled reator to provide a series capacitor reactance with uniform variations. UPFC is able to control transmission line voltage, impedance, and angle simultaneously or optionally and it can control real and reactive power flow in line. Also, it can compensate reactive power in parallel with independent control capability. SVC is a static generator of reactive power in which output are changed in a way that specific parameters in electric power systems are preserved or controlled. The present paper considered these three components of FACTS technology which are able to increase control and efficiency of transmission lines to achieve higher level of power systems reliability. DOI: 10.5901/mjss.2015.v6n6s2p728

Fuzzy Genetic Algorithm Approach for the Optimal Placement of Flexible AC Transmission Systems Devices in a Power System

—This article presents a novel approach for optimal flexible AC transmission systems devices planning in an interconnected power system under different loading conditions. The static VAR compensator and thyristor-controlled series capacitor are two types of flexible AC transmission systems devices considered for optimal power system operation. In the proposed approach, a fuzzy membership function is used to determine weak nodes in the power system for the placement of static VAR compensators as a flexible AC transmission systems device. The thyristor-controlled series capacitor is the other type of flexible AC transmission systems devices for which its positions are determined by the reactive power flow in lines. The genetic algorithm is used for the optimal setting of the power system variables, including flexible AC transmission systems devices. The proposed technique is compared with other optimization methods using different globally accepted evolutionary algorithms where the nodes or point of VAR compensation is determined by eigenvalue analysis, and the amount of flexible AC transmission systems devices is determined by evolutionary techniques, such as the genetic algorithm, differential evolution, and particle swarm optimization. The superiority of the proposed fuzzy-based optimization approach is established by the results and comparative analysis with other methods.

Fuzzy based evolutionary algorithm for reactive power optimization with FACTS devices

In this paper, optimization techniques such as Genetic Algorithm (GA) and Differential Evolution (DE) along with Fuzzy Logic (FL) is used for the optimal setting of power system variables, including Flexible AC Transmission Systems (FACTS) devices. Here, two types of FACTS devices, Thyristor Controlled Series Compensator (TCSC) and Static Var Compensator (SVC) are used for the optimal operation of the power system as well as in reducing congestion in transmission lines. Optimal placement of FACTS devices in the heavily loaded power system reduces transmission loss, controls reactive power flow, improves voltage profile of all nodes and also reduces operating cost. In this proposed approach fuzzy membership function is used for the selection of weak nodes in the power system for the placement of SVC’s as one of the FACTS devices while the location of TCSC’s are determined by the reactive power flow in lines. The proposed technique is compared with other optimization methods using different globally accepted evolutionary algorithms where the nodes are detected by eigen value analysis and the amount of FACTS devices are determined by evolutionary techniques like, Genetic Algorithm (GA), Differential Evolution (DE) and Particle Swarm Optimization (PSO). The superiority of the proposed fuzzy based optimization approach is established by the results and the comparative analysis with other methods.

Reactive Power Optimization with SVC & TCSC using Genetic Algorithm

In this paper Genetic Algorithm (GA) is used as an evolutionary tecthniques for the optimal placement of flexible AC transmission systems (FACTS) devices in an interconnected power system. Here two types of FACTS devices has been discussed nemely, Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) for the economic operation and to reduce the transmission loss. Reactively loading of the system is taken from base to 200% of base loading and the system performance is observed without and with FACTS devices. Optimal placement of FACTS devices in the system is determined by calculating active and reactive power flow in lines. FACTS devices along with reactive generation of generators and transformer tap setting are used for the power transfer capacity using GA. The proposed approach is applied on IEEE 14 and IEEE 30-bus test systems. Finally the effectiveness of the proposed GA based method of placement of FACTS devices is established by comparing the results with another standard method of optimization like Particle Swarm Optimization (PSO) technique.

Available Transfer Capability Determination Incorporating Reactive Power Flows and Network Uncertainties under a Deregulated Environment

As deregulation unfolds and privatization of the power sector takes shape, a host of new technical challenges is generated to market participants and power system researchers. One of the key concepts is to quantify the remaining transfer capability in the supply system for further transactions, which is termed “available transfer capability.” Generally, in available transfer capability determination using linear sensitivity factors, such as power transfer distribution factors, the effect of reactive power flow in lines is neglected. This leads to a number of potential errors in available transfer capability calculation, and accuracy is very much affected. The main contribution of this article is to describe a simple, fast, and non-iterative method that incorporates the effect of reactive power flow directly in available transfer capability determination. A new set of distribution factors, namely the apparent power transfer distribution factor for base-case operation and the line outage apparent power transfer distribution factor for contingency-case operation, has been introduced. Since the capability of a system is highly affected by network uncertainties, single-area available transfer capability and multi-area available transfer capability are estimated for the system uncertainties using the above factors. The validity of the proposed method has been tested on IEEE 30-bus system and a practical Indian utility 69-bus system. The accuracy of the proposed method is analyzed by comparing with Newton–Raphson load flow program results.

Distribution factors of reactive power flow in transmission line and transformer outage studies

The authors present a fast and accurate method to calculate a set of distribution factors of reactive power flow for transmission line and transformer outage studies. The transmission branches are broken into two categories: transmission lines and transformers. Separate formulas are derived to calculate the distribution factors of the reactive power flow. A transmission line model is developed. The reactive power flow in a line is divided into two parts: the transmission part and the loss part. Based on this model, transmission line outages were simulated by power injections which cancel the reactive power flow in the outage lines. Formulas to calculate the distribution factors of the reactive power flow are derived using the decoupled load flow characteristic, network sensitivities, and the principle of superposition. The formulas to calculate the distribution factors of the reactive power flow in transformers are also derived. >