A Relay Scheme for Distribution Networks Considering the Control Mode of Inverter-Based Distributed Generator

2013 ◽  
Vol 805-806 ◽  
pp. 801-804
Author(s):  
Yan Xia Zhang ◽  
Yan Li

In the distribution system including distributed generators, it is difficult to meet the requirements of selectivity and sensitivity for traditional current protection. Currently, inverter-based distributed generators (IBDG) are widely used in distribution systems. The transient process of IBDG is rapid, and its transient characteristics are influenced by the control strategy. The controlled current source equivalent model of IBDG with positive-sequence P-Q control is put forward. After analyzing the fault characteristics, the protection scheme using negative sequence current is proposed, which can be used in the distribution systems including IBDG under positive-sequence P-Q control. The simulation results on a 10kV distribution system have verified the correctness of faults characteristics and the effectiveness of protection scheme.

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2909 ◽  
Author(s):  
Aristotelis Tsimtsios ◽  
Dionisis Voglitsis ◽  
Ioannis Perpinias ◽  
Christos Korkas ◽  
Nick Papanikolaou

The upcoming adoption of low-voltage-ride-through requirements in low-voltage distribution systems is expected to raise significant challenges in the operation of grid-tied inverters. Typically, these inverters interconnect photovoltaic units, which are the predominant distributed energy resource in low-voltage distribution networks, under an umbrella of standards and protection schemes. As such, a challenging issue that should be considered in low-voltage distribution network applications, regards the coordination between the line protection scheme (typically consisting of a non-settable fuse) and the low-voltage-ride-through operation of photovoltaic generators. During a fault, the fuse protecting a low-voltage feeder may melt, letting the generator to continue its ride-through operation. Considering that the efficacy/speed of the anti-islanding detection is affected by ride-through requirements, this situation can lead to protracted energization of the isolated feeder after fuse melting (unintentional islanding). To address this issue, this paper proposes a fault-current-limitation based solution, which does not require any modification in the existing protection scheme. The operation principles, design, and implementation of this solution are presented, while, its effectiveness is supported by extensive simulations in a test-case low-voltage distribution system. A discussion on the presented results concludes the paper.


2012 ◽  
Vol 622-623 ◽  
pp. 1882-1886
Author(s):  
Hadi Zayandehroodi ◽  
Azah Mohamed ◽  
Hussain Shareef ◽  
Masoud Farhoodnea ◽  
Marjan Mohammadjafari

The presence of renewable distributed generator (RDG) in a distribution system will have unfavorable impact on the operating system because the distribution system is no longer radial in nature and is not supplied by a single main power source. With RDGs in a distribution network, it brings about a change in the fault current level of the system and causes many problems in the protection system, such as false tripping of protective devices, protection blinding, an increase and decrease in short-circuit levels. This paper presents the effect of RDGs on the fault current level of the system. The operating protection issues particularly in cases where RDGs are added to a LV distribution feeder are also discussed.


2014 ◽  
Vol 496-500 ◽  
pp. 1457-1463
Author(s):  
Yan Xu ◽  
Qin Cheng Yuan ◽  
Xiao Yun Huang ◽  
Lan Jiang

A model is established to research on the applicability of network protection in theory. In this model, distributed power generation with constant power (PQ) control mode which is equivalent to a voltage control current source is taken as the research object. Fault ride-through control theory is used to analyze the influence on the network protection exerted by three-phase short-circuit fault. In this paper, the equivalent model of the distributed generation is offered firstly. Then the three-phase short-circuit fault characteristics are illustrated based on the equations of the access points voltage and the distributed generations current. In the end, a simulation model is built to verify that the network protection can be applied to settle the three-phase short-circuit fault in the distributed network with distributed generation.


2016 ◽  
Vol 17 (2) ◽  
pp. 131-141 ◽  
Author(s):  
Neelakanteshwar Rao Battu ◽  
A. R. Abhyankar ◽  
Nilanjan Senroy

Abstract Distributed Generation has been playing a vital role in dealing issues related to distribution systems. This paper presents an approach which provides policy maker with a set of solutions for DG placement to optimize reliability and real power loss of the system. Optimal location of a Distributed Generator is evaluated based on performance indices derived for reliability index and real power loss. The proposed approach is applied on a 15-bus radial distribution system and a 18-bus radial distribution system with conventional and wind distributed generators individually.


Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.


Mathematics ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 158
Author(s):  
Farzaneh Pourahmadi ◽  
Payman Dehghanian

Allocation of the power losses to distributed generators and consumers has been a challenging concern for decades in restructured power systems. This paper proposes a promising approach for loss allocation in power distribution systems based on a cooperative concept of game-theory, named Shapley Value allocation. The proposed solution is a generic approach, applicable to both radial and meshed distribution systems as well as those with high penetration of renewables and DG units. With several different methods for distribution system loss allocation, the suggested method has been shown to be a straight-forward and efficient criterion for performance comparisons. The suggested loss allocation approach is numerically investigated, the results of which are presented for two distribution systems and its performance is compared with those obtained by other methodologies.


Author(s):  
Sayed Mir Shah Danish ◽  
Mikaeel Ahmadi ◽  
Atsushi Yona ◽  
Tomonobu Senjyu ◽  
Narayanan Krishna ◽  
...  

AbstractThe optimal size and location of the compensator in the distribution system play a significant role in minimizing the energy loss and the cost of reactive power compensation. This article introduces an efficient heuristic-based approach to assign static shunt capacitors along radial distribution networks using multi-objective optimization method. A new objective function different from literature is adapted to enhance the overall system voltage stability index, minimize power loss, and to achieve maximum net yearly savings. However, the capacitor sizes are assumed as discrete known variables, which are to be placed on the buses such that it reduces the losses of the distribution system to a minimum. Load sensitive factor (LSF) has been used to predict the most effective buses as the best place for installing compensator devices. IEEE 34-bus and 118-bus test distribution systems are utilized to validate and demonstrate the applicability of the proposed method. The simulation results obtained are compared with previous methods reported in the literature and found to be encouraging.


2014 ◽  
Vol 529 ◽  
pp. 455-459
Author(s):  
Nan Xu ◽  
Shan Shan Li ◽  
Hao Ming Liu

Considering the probabilistic of the wind power and the solar power, a fault recovery method for distribution systems with the wind power and the solar power is presented in this paper. For the wind power, a simplified steady-state equivalent model of an asynchronous wind generator is added into the Jacobian matrix to consider the impact of the wind power on systems. For the solar power, its output is considered as an injected power which is related with solar irradiance. Three-point estimate is employed to solve the probabilistic power flow of distribution systems with the wind power and the solar power. The restoration is described as a multi-objective problem with the mean of the system loss and the number of switch operations. Fast elitist non-dominated sorting partheno-genetic algorithm is used to solve this multi-objective problem. IEEE 33-bus system is used as an example and the results show that the models and algorithms in this paper are efficient.


Author(s):  
Razan Al Rhia ◽  
Haithm Daghrour

Monitoring and controlling the electrical distribution system for real time is becoming very important to improve its operating performance after transition to active distribution systems. So, many sensors are needed to monitor all parts in the systems. But if sensors are installed at all buses, investment cost becomes huge. To reduce the number of sensors, state estimation approach can be used to estimate the voltage of buses, which do not have sensors. State Estimation (SE) algorithms are broadly classified into Static State Estimator (SSE) and Dynamic State Estimator (DSE). This chapter classifies most algorithms used in active distribution networks, also State estimation in unbalanced distribution systems, and Role of PMU in Distribution System State Estimation.


2018 ◽  
Vol 7 (3) ◽  
pp. 223-231
Author(s):  
Saad Muftah Saad ◽  
Naser El Naily ◽  
Faisal A. Mohamed

The environmental and economic features of renewable energy sources have made it possible to be integrated as Distributed Generation (DG) units in distribution networks and to be widely utilized in modern distribution systems. The intermittent nature of renewable energy sources, altering operational conditions, and the complex topology of active distribution networks makes the level of fault currents significantly variable. Thus, the use of distance protection scheme instead of conventional overcurrent schemes offers an appropriate alternative for protection of modern distribution networks. In this study, the effect of integrating multiple DG units on the effective cover of distance protection schemes and the coordination between various relays in the network was studied and investigated in radiology and meshed operational topologies. Also, in cases of islanded and grid-connected modes. An adaptive distance scheme has been proposed for adequate planning of protection schemes to protect complex networks with multiple distribution sources. The simplified simulated network implemented in NEPLAN represents a benchmark IEC microgrid. The comprehensive results show an effective protection measure for secured microgrid operation.Article History: Received October 18th 2017; Received in revised form May 17th 2018; Accepted July 8th 2018; Available onlineHow to Cite This Article: Saad, S.M., Naily, N.E. and Mohamed, F.A. (2018). Investigating the Effect of DG Infeed on the Effective Cover of Distance Protection Scheme in Mixed-MV Distribution Network. International Journal of Renewable Energy Development, 7(3), 223-231.https://doi.org/10.14710/ijred.7.3.223-231


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