Study on Stability and Reactive Power Optimization of Active Distribution Network Based on Bifurcation Theory

2015 ◽  
Vol 734 ◽  
pp. 701-706
Author(s):  
Xian Bin Dai

as the basic method used to analyze the stability of nonlinear dynamic system, it is able to more deeply discuss the stability problems of power system in the vicinity of a critical point in comparison with traditional analysis method. Active power distribution network is a complicated nonlinear dynamic system. The change of voltage stability is the process to convert from stable status to bifurcation in essence. Taking 10-node active distribution system as an example, the author studies the influence of reactive power optimization on voltage stability based on bifurcation theory. The author explains the reactive optimization algorithm based on numerical simulation, namely, it is the decision - making algorithm in order to realize multiple purposes of having minimum power network loss, largest reactive power margin with stable operation of power distribution network and minimum voltage floating in system fluctuation, which is proved to be effective in elevating power distribution system stability, reducing power loss and improving voltage quality.

Author(s):  
Akram Qashou ◽  
Sufian Yousef ◽  
Abdallah A. Smadi ◽  
Amani A. AlOmari

AbstractThe purpose of this paper is to describe the design of a Hybrid Series Active Power Filter (HSeAPF) system to improve the quality of power on three-phase power distribution grids. The system controls are comprise of Pulse Width Modulation (PWM) based on the Synchronous Reference Frame (SRF) theory, and supported by Phase Locked Loop (PLL) for generating the switching pulses to control a Voltage Source Converter (VSC). The DC link voltage is controlled by Non-Linear Sliding Mode Control (SMC) for faster response and to ensure that it is maintained at a constant value. When this voltage is compared with Proportional Integral (PI), then the improvements made can be shown. The function of HSeAPF control is to eliminate voltage fluctuations, voltage swell/sag, and prevent voltage/current harmonics are produced by both non-linear loads and small inverters connected to the distribution network. A digital Phase Locked Loop that generates frequencies and an oscillating phase-locked output signal controls the voltage. The results from the simulation indicate that the HSeAPF can effectively suppress the dynamic and harmonic reactive power compensation system. Also, the distribution network has a low Total Harmonic Distortion (< 5%), demonstrating that the designed system is efficient, which is an essential requirement when it comes to the IEEE-519 and IEC 61,000–3-6 standards.


Author(s):  
Jamal Abdul-Kareem Mohammed ◽  
Arkan Ahmed Hussein ◽  
Sahar R. Al-Sakini

<p>Power distribution network in Iraq still suffers from significant problems regarding electricity distribution level. The most important problem is the disturbances that are occurring on lines voltages, which in turn, will negatively affect sensitive loads they feed on. Protection of these loads could be achieved efficiently and economically using the dynamic voltage restorer DVR when installed between the voltage source and load to inject required compensation voltage to the network during the disturbances period. The DVR mitigates these disturbances via restoring the load voltage to a pre-fault value within a few milliseconds. To control the DVR work, dq0 transformation concept and PID method with sinusoidal pulse-width modulation SPWM based converter had been used to correct the disturbances and thus enhance the power quality of the distribution network. The DVR performance was tested by MATLAB/Simulink with all kinds of expected voltage disturbances and results investigated the effectiveness of the proposed method.</p>


2014 ◽  
Vol 668-669 ◽  
pp. 749-752 ◽  
Author(s):  
Xiao Yi Zhou ◽  
Ling Yun Wang ◽  
Wen Yue Liang ◽  
Li Zhou

Distributed generation (DG) has an important influence on the voltage of active distribution networks. A unidirectional power distribution network will be transformed into a bidirectional, multiple power supply distribution network after DGs access to the distribution network and the direction of power flow is also changed. Considering the traditional forward and backward substitution algorithm can only deal with the equilibrium node and PQ nodes, so the other types of DGs should be transformed into PQ nodes, then its impact on active distribution network can be analyzed via the forward and backward substitution algorithm. In this paper, the characteristics of active distribution networks are analyzed firstly and a novel approach is proposed to convert PI nodes into PQ nodes. Finally, a novel forward and backward substitution algorithm is adopted to calculate the power flow of the active distribution network with DGs. Extensive validation of IEEE 18 and 33 nodes distribution system indicates that this method is feasible. Numerical results show that when DG is accessed to the appropriate location with proper capacity, it has a significant capability to support the voltages level of distribution system.


2019 ◽  
Vol 11 (1) ◽  
pp. 46-52
Author(s):  
Hong WANG ◽  
Zhijie WANG

 In order to solve the problem of reactive power optimization of distribution network with distributed power supply, the multi-objective reactive power optimization function is established from multiple perspectives, and the equation constraint and inequality constraint equation of power system are considered. Secondly, taking IEEE33 node distribution system with distributed power supply as an example, reactive power optimization of single objective function is carried out to verify that the proposed algorithm has a global convergence and a great advantage in convergence speed. Finally, multi-objective reactive power optimization of distribution network with distributed power supply is carried out. Simulation results demonstrate the effectiveness of the proposed algorithm.


2014 ◽  
Vol 644-650 ◽  
pp. 2577-2580
Author(s):  
Xiao Quan Li ◽  
Shuai Liu ◽  
Wei Qun Yang

In the case that a single fault occurs on a power feeder in the one-source distribution system, the directional layered model of the network which reflects the layered topological characteristic of the network was built up. Then a new algorithm for fault detection in power distribution network was proposed to locate the faulty sections in distribution feeder network. The algorithm itself as well as its program design is simple. It can be applied to complex distribution systems with multi-sources. It is proved correct by an example.


2014 ◽  
Vol 960-961 ◽  
pp. 1077-1080 ◽  
Author(s):  
Bo Lun Wang

Near the load of distribution network access distributed networks, the entire distribution network load distribution will change, system trend then change, then the trend of the distribution network can also be changed from the original "one-way flow" to "two-way flow". For synchronous generator connected to the power distribution network, the input active power and reactive power at the same time to the system, can reduce the loss and the voltage distribution network can play a supporting role, but for asynchronous induction generator connected to the power distribution network, the input to the system active power and reactive power absorption, reduce the power factor of the grid. By trend analysis found that introducing asynchronous induction generator to increase distribution network loss, deterioration in transmission line voltage level. Distributed generators after introducing the distribution network could reduce may also increase the system network loss.


2014 ◽  
Vol 484-485 ◽  
pp. 650-654
Author(s):  
Xu Yang

Article systematic analysis of rural power grid situation, use of existing data resources and distribution lines to achieve the level of automation for reactive power optimization, operation optimization and concrete implementation. Papers able to give a complete, scientific and reasonable reactive power optimization. While article takes DSP2812 as core to developed reactive power compensation controller, to achieve the reactive power compensation, power distribution network detection information, and send messages via GPRS, remote control compensation capacitors. Configuration parameter has a flexible, reliable, convenient and practical features.


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