M. Arun Bhaskar

Voltage Profile Improvement Using FACTS Devices: A Comparison between SVC, TCSC and TCPST

If the reactive power of the load is changing rapidly, then a suitable fast response compensator is needed Static VAR Compensator (SVC) thyristor control series compensator (TCSC) and thyristor control phase shift transformer (TCPST) is such a compensator which belongs to FACTS family. The ultimate objective of applying reactive shunt compensation in the line is to improve the voltage profile. The inclusion of the FATCS devices in the circuit improves the reactive power in the line. FACTS are successfully simulated and the results show the voltage profile improvement.

A simple PV array modeling using MATLAB

This paper presents the general overview on the requirement of renewable energy mainly the solar power. We have also dealt with the types of solar power available and the basic modeling of solar energy system mainly the photo voltaic type has been discussed. MATLAB Simulink has been used as a tool to provide the I-V and P-V plots of the system.

Voltage Quality Improvement Using DVR

The problem of voltage sags and Swells and its severe impact on sensitive loads is well known. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is one of the most efficient and effective modern custom power devices used in power distribution networks. This paper described DVR principles and voltage correction methods for balanced and/or unbalanced voltage sags and swells in a distribution system. Simulation results were presented to illustrate and understand the performances of DVR under voltage sags/swells conditions. The results obtained by simulation using MATLAB confirmed the effectiveness of this device in compensating voltage sags and swells with very fast response (relative to voltage sag/swell time).

Stability Index Based Voltage Collapse Prediction and Contingency Analysis

Voltage instability is a phenomenon that could occur in power systems due to stressed conditions. The result would be an occurrence of voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction is an important part of power system planning and operation, and can help ensure that voltage collapse due to voltage instability is avoided. Line outages in power systems may also cause voltage collapse, thereby implying the contingency in the system. Contingency problems caused by line outages have been identified as one of the main causes of voltage instability in power systems. This paper presents a new technique for contingency ranking based on voltage stability conditions in power systems. A new line stability index was formulated and used to identify the critical line outages and sensitive lines in the system. Line outage contingency ranking was performed on several loading conditions in order to identify the effect of an increase in loading to critical line outages. Correlation studies on the results obtained from contingency ranking and voltage stability analysis were also conducted, and it was found that line outages in weak lines would cause voltage instability conditions in a system. Subsequently, using the results from the contingency ranking, weak areas in the system can be identified. The proposed contingency ranking technique was tested on the IEEE reliability test system.

A new control scheme for unified power quality conditioner (UPQC)

This paper presents a solution to the control of a unified power quality (PQ) conditioner (UPQC) for Power Quality improvement in power distribution systems. The problem formulation allows not only harmonic compensation but also voltage sags/swells, load demand changes, and power factor correction to be tackled in a unified framework. The proposed controller combines the multivariable regulator theory with H^, loop shaping, so that zero steady-state error and insensitivity to supply frequency variations can be accomplished simultaneously. The effectiveness of the proposed controller is, in practice, verified by experimental studies on a single-phase power distribution system.

Non Linear Control of STATCOM

This paper presents an investigation on a voltage regulator for parallel operated isolated synchronous generators supplying 3-phase 4-wire loads driven by constant speed prime mover like diesel engine, bio-mass, gasoline, hydro turbine unit etc. The proposed voltage regulator is realized using a STATCOM (static compensator) for providing the reactive power compensation, and load balancing. Three single-phase thyristors based VSC along-with three single-phase transformers and self supporting DC bus is used as a voltage controller for supplying 3-phase 4-wire loads. The neutral point of the load is achieved using neutral point of the excitation capacitors and primary windings terminal of the transformers. The proposed isolated electrical generating system is modeled and simulated on MATLAB using Simulink and PSB (Power System Blockset) toolboxes. The performance of proposed voltage controller for isolated synchronous generators is demonstrated while feeding loads.

Line outage contingency screening and ranking for voltage stability assessment

This paper presents the voltage stability based weak area clustering techniques in power system. The techniques employed voltage stability analysis (VSA) and Line outage contingency analysis (LOCA). From the VSA and LOCA, the most critical lines in a system during stressed condition are identified. A predeveloped voltage stability index was utilized as an indicator to voltage stability condition of the system. The weak areas formed by the lines are identified as the most critical lines. The results show that the lines which are identified as the weak lines from stability analysis. The proposed technique was implemented on IEEE reliable test system and the results show that distinct weak areas were identified when the system was closed to the stressed Condition.

Impact of FACTS devices on distance protection in transmission system

Due to the development in the field of Power Electonics many FACTS devices such as SVC, STATCOM, TCSC, UPSC are introduced in transmission lines. These devices are used to improve the system voltage profile, stability, Powerflow etc. Distance Relays are unique devices used to protect the transmission line from various faults. The reach of the relay is independent of the type of fault. Distance Relays are very sensitive to the apparent impedance seen by the relay and its zones. When a FACTS device say as TCSC is incorporated into the existing transmission line in order to improve the voltage profile, power flow, stability, etc it introduce problems in distance protection scheme in the measurement of the apparent impedance seen by the relay. Due to this significant change in the apparent impedance seen by the relay, it will lead to the mal operation of distance relay. This paper presents about the maloperation of distance protection of transmission line, when it is compensated by a series compensating device such as Thyrister Controlled Seies Capacitor(TCSC).

Application of integrated wind energy conversion system (WECS) and photovoltaic (PV) solar farm as Statcom to regulate grid voltage during night time

This paper presents the concept of utilizing photovoltaic (PV) solar farm (SF) as flexible ac transmission system controller-static synchronous compensator, to regulate the point of common coupling voltage during night time when the SF is not producing any active power. The proposed control will enable increased connections of WECS to the grid. MATLAB/Simulink based simulation results are presented for validation of the system.

Thyristor Controlled Series Capacitor as an Optimizer in an Electrical Market

This paper presents an overview over different areas where FACTS devices can improve transmission system efficiency especially under the condition of liberalized electricity markets. Furthermore, a network example, is shown where the installation of Thyristor Controlled Series Capacitor (TCSC) increases the transfer capacity into a region considerably while maintaining security margins. This can help to reduce or even eliminate congestion in a transmission network.