Effect of nonlinear load on design of dynamic compensator for reactive power modulation in AC/DC power system

Author(s):  
M.A. Choudhry ◽  
K. Lateef
2018 ◽  
Vol 57 ◽  
pp. 03003
Author(s):  
Xiao Fan ◽  
Zhou Kunpeng ◽  
Wang Tao ◽  
Cao Kan ◽  
Rao Yuze

In order to cope with the great pressure caused by the gradually exhaustion of fossil energy and environmental protection and climate warming, the development and application of the renewable energy has become an important foundation and development direction in the field of energy. However, due to the impact of energy and resource endowment, China’s load center and renewable energy base into the characteristics of long-range reverse distribution, the use of long-distance large-capacity transmission potential is necessary. With the “strong DC system and weak AC system” problem of the company power grid is increasingly prominent, the higher demand of dynamic reactive power support is put forward in the UHV DC power transmission project. Then, the large-capacity dynamic reactive power of new generation synchronous condenser is large-scale built up in the UHV DC/AC power system. Due to the high requirement of response speed and capacity in the UHV DC power transmission, the structure, dynamic characteristics, excitation control and relay protection and other aspects of the large synchronous condenser are different from generators and traditional synchronous condenser. Based on this, the dynamic reactive power demand of UHV DC power system is analyzed in this paper. Then, the main situation of large synchronous condenser is considered. In addition, the key points of the excitation control system and protection system are also discussed in this paper. There are important theoretical and practical significance for the safe and reliable operation of the UHV DC/AC power system.


This paper presents multifunctional operation capability of three level cascade H bridge inverter for grid connected solar pv application. The solar panel and inverter are modelled for unbalance and nonlinear loads with three control techniques (pq,dq,cpt) and its performance is simulated in the MATLAB environment using SIMULINK and Sim Power System (SPS) toolboxes. The performance of inverter is evaluated for harmonics elimination, power factor correction apart from active and reactive power support to grid and nonlinear load .Performance of three level H bridge inverter is evaluated for both PV mode and STATCOM mode using three control techniques for distribution grid.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3308
Author(s):  
Xingpeng Li

Though the full AC power flow model can accurately represent the physical power system, the use of this model is limited in practice due to the computational complexity associated with its non-linear and non-convexity characteristics. For instance, the AC power flow model is not incorporated in the unit commitment model for practical power systems. Instead, an alternative linearized DC power flow model is widely used in today’s power system operational and planning tools. However, DC power flow model will be useless when reactive power and voltage magnitude are of concern. Therefore, a linearized AC (LAC) power flow model is needed to address this issue. This paper first introduces a traditional LAC model and then proposes an enhanced data-driven linearized AC (DLAC) model using the regression analysis technique. Numerical simulations conducted on the Tennessee Valley Authority (TVA) system demonstrate the performance and effectiveness of the proposed DLAC model.


Author(s):  
Shaik Nagul Sharif and Sri Latha Veerla

The power quality problem in the power system is increased with the use of non-linear devices. Due to the use of non-linear devices like power electronic converters, there is an increase in harmonic content in the source current. Due to this there is an increase in the losses, instability and poor voltage waveform. To mitigate the harmonics and provide the reactive power compensation, we use filters. There are different filters used in the power system. Passive filters provide limited compensation, so active filters can be used for variable compensation. In this work, a shunt active filter has been made adaptive using a Variable Leaky Least Mean Square (VLLMS) based controller. Proposed adaptive controller can be able to compensate for harmonic currents, power factor and nonlinear load unbalance. DC capacitor voltage has been regulated at a desired level using a PI controller and a self-charging circuit technique. But, this scheme as two disadvantages such as, tuning issues of current controller pre-requisites the traditional PI controller, which is controlled by intelligent based Hybrid-Fuzzy-Logic controller for achieving good performance features. The design concept of proposed intelligent Hybrid-Fuzzy controller for shunt active filter has been verified through simulation analysis and results are presented with proper comparisons.


2020 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Rakesh Kumar ◽  
Mr Anurage Khare

The stability of a power system is the ability of a power system to restore an operating state of equilibrium for a given initial operating condition after it has been subjected to a physical disturbance, most of the variables of the system being limited so that almost the entire system remains intact. Designing of a SPVWM controlled inverter that has to be made available for efficient power supply to the load of different types. The control of inverter has to be designed in order to enhance the system power supply. To achieve this a space vector pulse width modulation technique has been designed which is then used to provide pulses to the three leg inverter. To design a power quality enhancement device with a simplified architecture such that it will accommodate for the reactive power supply along with an improvement in the active power available at the load terminals. Thus it can be drawn from this work that while designing an inverter with SPVWM control strategy the proposed power quality enhancement device can serve the purpose with better results in terms of power and efficiency. This architecture can also be used in hybrid systems thus making it more reliable controlling method. The system designed is also fitted to feed different types of load like nonlinear load, balanced load and unbalanced load.


2020 ◽  
Vol 8 (6) ◽  
pp. 1004-1012

The power quality problem in the power system is increased with the use of non-linear devices. Due to the use of non-linear devices like power electronic converters, there is an increase in harmonic content in the source current. Due to this there is an increase in the losses, instability and poor voltage waveform. To mitigate the harmonics and provide the reactive power compensation, we use filters. There are different filters used in the power system. Passive filters provide limited compensation, so active filters can be used for variable compensation. In this paper, a shunt active filter has been made adaptive using a Variable Leaky Least Mean Square (VLLMS) based controller. Proposed adaptive controller can be able to compensate for harmonic currents, power factor and nonlinear load unbalance. DC capacitor voltage has been regulated at a desired level using a PI controller and a self-charging circuit technique. But, this scheme has two disadvantages such as, tuning issues of current controller pre-requisites the traditional PI controller, which is controlled by intelligent based Fuzzy-Logic controller for achieving good performance features. The design concept of proposed intelligent Fuzzy controller for shunt active filter has been verified through simulation analysis and results are presented with proper comparisons.


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