Reactive Power In Transmission Line Research Articles

Analysis of Reactive Power Flow in an Electric Power System

Optimal power flow analysis is a calculation to minimize an objective function, namely generation costs or transmission losses by regulating the active power and reactive power generation of each interconnected power system generator by taking into account certain limits. The growth of industrial loads which are dominated by inductive loads requires a fairly large reactive power supply. This reactive power requirement will of course reduce the available power that can be transmitted to the load. Reactive power flow in transmission lines will reduce the active power distribution capacity required by the load. Reactive power flow that is too large can also cause losses. However, this reactive power is also an important component in the stability of the electric power system. For this reason, the flow of active and reactive power in transmission lines needs to be regulated so that the capacity and stability of the electric power transmission system is maintained.

Active Power Flow Control Using Phase Shifting Transformer and UPFC in AC Transmission Line

Electrical power system is huge interconnected power system to meet the consumer demand without interruption and to maintain the stability, to utilize existing system to their maximum limit within stability limit of the system, to solve the congestion problem and improve the power flow in the line. Phase shifting transformer (PST) is used to control the active power flow in transmission line. This active flow control is obtained by adjusting phase angle of voltages at PST terminal. Unified power flow controller (UPFC) is facts device, it can control both the active and reactive power in transmission line by controlling the line parameter like voltage, phase angle and line impedance there by adjusting the line reactance in real time. The power system simulation model for PST and UPFC are developed in MATLAB. By simulating the model without PST and UPFC and then model with PST and UPFC is simulated to obtain the results. Results are compared for different loading condition to analyze the performance of the system with both the model. Keyword – PST, UPFC, Power flow control, active and reactive power, MATLAB/SIMULINK

Controlling of Reactive Power in Transmission Line using Facts Technology with Closed Loop Controller

The paper proposes the power flow control in the transmission line using FACTS devices. In the existing system the power flow in the line system is controlled by using STATCOM. In the proposed system we are going to implement the Combined FACTS device. Which is a combination of series and shunt controller like HPFC (Hybrid power flow controller). Comparison of open loop and closed loop are analyzed for fourteen bus system. In the closed loop PI and FOPID are analyzed for both FACTS Devices. The simulation of both open loop and closed loop are done in the Matlab software.

Optimized Reactive Power Compensation Using Fuzzy Logic Controller

Reactive power flow in a long transmission line plays a vital role in power transfer capability and voltage stability in power system. Traditionally, shunt connected compensators are used to control reactive power in long transmission line. Thyristor controlled reactor is used to control reactive power under lightly loaded condition. By controlling firing angle of thyristor, it is possible to control reactive power in the transmission lines. However, thyristor controlled reactor will inject harmonic current into the system. An attempt to reduce reactive power injection will increase harmonic distortion in the line current and vice versa. Thus, there is a trade-off between reactive power injection and harmonics in current. By optimally controlling the reactive power injection, harmonics in current can be brought within the specified limit. In this paper, a Fuzzy Logic Controller is implemented to obtain optimal control of reactive power of the compensator to maintain voltage and harmonic in current within the limits. An algorithm which optimizes the firing angle in each fuzzy subset by calculating the rank of feasible firing angles is proposed for the construction of rules in Fuzzy Logic Controller. The novelty of the algorithm is that it uses a simple error formula for the calculation of the rank of the feasible firing angles in each fuzzy subset.

PERFORMANCE ANALYSIS OF VARIOUS PARAMETERS BY COMPARISON OF CONVENTIONAL PITCH ANGLE CONTROLLER WITH FUZZY LOGIC CONTROLLER

This paper deals with a variable speed wind turbine coupled with a permanent magnet synchronous generator connected through a two mass drive train. This drive train is connected to synchronous generator and after the conversion process finally connected to grid and the idea of transmission over a long distance makes the use of converter necessary and at the receiving end. The inverter is used to convert it back and the inverter is designed with a proper gate signal to get the best output three phase voltages. The fuzzy logic controller is used to track generator speed with varying wind speed to optimize turbine aerodynamic efficiency in the outer speed loop. Pitch angle control of wind turbine has been used widely to reduce torque and output power variation in high rated wind speed areas .The machine side converter is designed to extract maximum power from the wind. In this work a WECS connected with grid is designed in Matlab and a Fuzzy controller is designed to improve the output and we can see the major difference in DC link voltage and reactive power in transmission line. From the outputs we can also go through the reactive power issue which system is best for inductive load or capacitive load. The simple PI system is good for capacitive load and the fuzzy system is better option for the inductive load. The results of both the system of normal controller and fuzzy controller is compared and analyzed.

Optimal location and signal selection of UPFC device for damping oscillation

Unified power flow controller (UPFC) is used for controlling the real and reactive power in transmission line and bus voltage simultaneously and independently. An additional task of UPFC is to increase transmission capacity as result of power oscillation damping. The effectiveness of this controller depends on its optimal location and proper signal selection in the power system network. A residue factor has been proposed to find the optimal location of the UPFC controllers and eigenvalue analyses are used to assess the most appropriate input signals (stabilizing signal) for supplementary damping control of UPFC to damp out the inter-area mode of oscillations. The proposed residue factor is based on the relative participation of the parameters of UPFC controller to the critical mode. A simple approach of computing the residue factor has been proposed, which combines the linearized differential algebraic equation model of the power system and the UPFC output equations. While for signal selection a right-half plane zeros (RHP zeros) and Hankel singular value (HSV) is used as tools to select the most receptive signal to a mode of the inter-area oscillation. The placements of UPFC controllers have been obtained for the base case and for the dynamic critical contingences. The effectiveness of the proposed method of placement and selection of signals are demonstrated on practical network of TNB 25 bus system of south Malaysian network and New England 39 bus system.