scholarly journals Regulation Principles of Power Flow Gradients to Multiple Characteristic Independent Variables in UPFC Embedded Power System

2020 ◽  
Vol 10 (5) ◽  
pp. 1720 ◽  
Author(s):  
Jinlian Liu ◽  
Jian Yang ◽  
Zheng Xu ◽  
Zheren Zhang ◽  
Pengcheng Song

The power flows in the unified power flow controller (UPFC) embedded system is mainly regulated by the two variables containing the magnitude and the phase angle of the output series inserted voltage (OSIV) of UPFC. Different value combinations of the two variables can form multiple regulation modes of OSIV, and the regulation principles and efficiencies for power flows are distinct by different regulation modes. This paper dedicates to research the regulation principles of active and reactive power flow gradients (PFG) to multiple characteristic independent variables (CIVs) at several selected critical points (SCP) of the system in different operation conditions. The CIVs contains the magnitude of OSIV, the phase angle of OSIV, and the phase difference of the system. First, multiple power flow regulation modes of OSIV are designed, the mathematical models of the PFG to each CIV at each SCP are established, and the theoretical principles for the PFG to each CIV at each SCP are analyzed and compared. Next, four typical operation conditions of the system and four regulation scenarios are assumed and case studies for the PFG to each CIV at different SCP are carried out. The test results at each SCP are analyzed both in the two-dimensional planes and three-dimensional spaces. The regulation principles and efficiencies of PFG to each CIV at different SCP are compared with each other and summarized, which can offer useful references for practical engineering and applications of UPFC.

Now days’ electrical power requirement has enlarged expanding as expansion & restructuring of electrical power system (PS) for generation & transmission in power sector is critically limited due to current resources & environmental circumstances. As outcome, approximately of corridors of power transmission overhead lines are greatly loaded & congested. Also major issue of power system voltage stability becomes power transfer restricted and capability issue. A Modern power electronics technology FATCS considered device Static Synchronous Series Compensator (SSSC) is VSC demanded series FACTS equipment. Unified power flow controller (UPFC) is to manage power flow (PF), voltage magnitude & phase angle. In this research paper suggested to maintain voltage magnitude as well as PF of faulty lines. The consequence of mutation of PS parameters like voltage, phase angle, active power, reactive power, & overall power factor with & without SSSC & UPFC have also incorporated. Assessment of PS safety is essential in society to expand customs to sustain system functions when one or more components fail. A PS is "secure" when it can defy loss of one or more ingredients & still go on working without major problems. The Contingency event investigation technique is taken to identify electrical node PF in faulty transmission lines (TL). The Performance of PS has been tested on IEEE 14-Bus System.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Asaad Shemshadi ◽  
Pourya Khorampour

Abstract In recent years, the use of wind energy to generate electricity in the world has been accelerating and growing. Wind farms are unstable when dynamic voltage fluctuations occur, especially sudden and sudden changes in load, and show oscillating performance at their output. In this paper, the Unified Power Flow Controller (UPFC) has been simulated and studied by Matlab software to improve the dynamic stability and transient behavior of the wind power plant in the event of sudden load changes. The simulation results show that by controlling the UPFC series inverter, voltage fluctuations in the PCC bus are prevented and the UPFC parallel inverter injects power after changing the load for faster recovery and stability of the PCC bus voltage and thus the stability of the wind farm. The UPFC can control the active and reactive power at the transmission line, and in fact, controls the output of the wind turbine with the generator from both sides to the fluctuations caused by sudden load changes that play a role such as sudden disturbances and oscillating errors. Also, the presence of UPFC in the system reduces power fluctuations.


Author(s):  
A. Naveena ◽  
M.Venkateswara Rao

The equipments based on the power electronics have been improved under the name of Flexible Alternating Current Transmission Systems (FACTS) in the last years. Unified Power Flow Controller (UPFC) is the most widely used FACTS device to control the power flow and to optimize the system stability in the transmission line. UPFC is a FACTS devices that can control active and reactive power flow in transmission line by means of injection controllable series voltage to the transmission line. This paper proposes a new connection for a Unified Power Flow Controller (UPFC) to control the active and reactive power flow control in two sides of a transmission line independently and it regulates bus voltage in the same transmission line, furthermore it is possible to balance line current too. This connection of the UPFC will be called an center node UPFC (C_UPFC). It is one of the newest devices within the FACTS technology. The structure and capability of the C_UPFC is discussed and its control scheme is based on the d-q orthogonal coordinates. According to this, the performance of UPFC for several modes of operations using different control mechanisms based on Proportional-Integral (PI) and PID based controllers has been studied. The obtained simulation results from Matlab/simulink confirm the effective features.


Author(s):  
Anuj Singh ◽  
Dr. Sandeep Sharma ◽  
Karan Sharma ◽  
Flansha Jain ◽  
Shreyanshu Kumar Jena

A Power System is actually a vast system that requires an outstanding plan for maintaining the continual flow of electricity. When a fault occurs at the power system, number of difficulties arises because of transients in system. so to attenuate these transients, power electronics based devices like FACTS are utilized. A unified power flow controller (UPFC) is one among different power electronics controller which can dispense VAR compensation, line impedance control and phase shifting. The thought is to see potential of UPFC to require care of active and reactive power movement within the compensated line (including UPFC) and to shrink the falloff of the bus voltage in case of grounding fault within the cable. power system block consisting of simulink is used for numerical analysis. Simulation outcomes from MATLAB reflects major improvement in the overall system’s behaviour with UPFC in sustain the voltage and power flow even under severe line faults by proper injection of series voltage into the cable at the point of connection. outcomes shows how the UPFC contributes effectively to a faster regaining of the power system to the pre-fault conditions.


Author(s):  
S. Ali Al-Mawsawi ◽  
Mohammed R. Qader

It has recently been illustrated that the Unified Power Flow Controller (UPFC) installation location plays an important role in effecting nonlinearly in the UPFC steady state performance of the system. A Pulse Width Modulation (PWM) based on UPFC as a voltage regulator is modeled and analyzed to investigate the optimal position in the transmission line. From the study made in this paper, it is shown that the location of UPFC plays a significant part in effecting nonlinearly. It is also found from the simulation results that the distribution of the active and reactive power flows can be controlled by varying the modulation index of the device. 


2019 ◽  
Vol 8 (4) ◽  
pp. 11456-11459

Generally, power system faces the problem to transfer power from one system to another system without any fluctuations, with minimal of system losses. To overcome this problems, a flexible ac transmission system is implemented in this paper. In present scenario, facts devices are used to reduce the transmission losses for improvising transmission capacity and also to improve the system capability. Unified Power Flow Controller plays a most prominent role in FACTS controller to improve the system stability. The structure of UPFC is combination of back-back converters with boosting and zigzag transformer. This type of UPFC system consists of high losses due to presence of magnetic properties in this transformer. With this, a transformer-less multilevel inverter based UPFC topology is proposed in this paper. This paper focuses on the modulation of transformerless UPFC with PSO, which controlsfundamental frequency for better controlling of active and reactive power, harmonic minimization, and improvement in efficiency of system by controlling DC link voltage


2020 ◽  
Vol 9 (5) ◽  
pp. 1755-1765
Author(s):  
Mohammed Y. Suliman ◽  
Mahmood T. Al-Khayyat

The power flow controlled in the electric power network is one of the main factors that affected the modern power systems development. The unified power flow controller (UPFC) is a FACTS powerful device that can control both active and reactive power flow of parallel transmission lines branches. In this paper, modelling and simulation of active and reactive power flow control in parallel transmission lines using UPFC with adaptive neuro-fuzzy logic is proposed. The mathematical model of UPFC in power flow is also proposed. The results show the ability of UPFC to control the flow of powers components "active and reactive power" in the controlled line and thus the overall power regulated between lines.


Author(s):  
Jaya Raju Gaddala ◽  
Sambasiva Rao Gudapati

Harmonics reduction techniques in source current were found to be unreliable and imbalanced with different load conditions. This certain unreliability problem in harmonics mitigation is caused by non-linear loads. The harmonics and power quality problems are eliminated by filters. These filters are expensive to provide a dynamic response under various load conditions. The new unified power flow controller composed of a series and shunt compensator provides more secured power systems and good voltage stability at various load conditions. D-Q theory is used to generate the reference current from the AC source current. D-Q theory produces sinusoidal harmonics that are opposite to load harmonics. This UPFC can absorb or inject reactive power in the PCC. D-Q theory followed by a hysteresis current controller generates PWM pulses to the shunt and series compensator. The PI and fuzzy logic controllers preserve the DC link voltage in the storage capacitor. The proposed technique has been simulated by using Matlab simulation under different load conditions.


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