Effect of Distributed Photovoltaic Generation on Short-Circuit Currents and Fault Detection in Distribution Networks: A Practical Case Study

The increase in the installation of renewable energy sources in electrical systems has changed the power distribution networks, and a new scenario regarding protection devices has arisen. Distributed generation (DG) might produce artificial delays regarding the performance of protection devices when acting as a result of short-circuits. In this study, the preliminary research results carried out to analyze the effect of renewable energy sources (photovoltaic, wind generation, etc.) on the protection devices of a power grid are described. In order to study this problem in a well-defined scenario, a quite simple distribution network (similar to the ones present in rural areas) was selected. The distribution network was divided into three protection zones so that each of them had DG. In the Institute of Electrical and Electronic Engineers (IEEE) system 13 bus test feeder, the short-circuits with different levels of penetration were performed from 1 MVA to 3 MVA (that represent 25%, 50%, and 75% of the total load in the network). In the simulations carried out, it was observed that the installation of DG in this distribution network produced significant changes in the short-circuit currents, and the inadequate performance of the protection devices and the delay in their operating times (with differences of up to 180% in relation to the case without DG). The latter, that is, the impacts of photovoltaic DG on the reactions of protection devices in a radial distribution network, is the most relevant outcome of this work. These are the first results obtained from a research collaboration framework established by staff from ETSI Civil and the IDR/UPM Institute, to analyze the effect of renewable energy sources (as DG) on the protection devices of a radial distribution network.

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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 ◽

10.14710/ijred.7.3.223-231 ◽

2018 ◽

Vol 7 (3) ◽

pp. 223-231

Author(s):

Saad Muftah Saad ◽

Naser El Naily ◽

Faisal A. Mohamed

Keyword(s):

Renewable Energy ◽

Distribution Systems ◽

Renewable Energy Sources ◽

Distribution Network ◽

Distribution Networks ◽

Energy Sources ◽

Distance Protection ◽

Protection Measure ◽

Protection Scheme ◽

Modern Distribution

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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Robust Fault Protection Technique for Low-Voltage Active Distribution Networks Containing High Penetration of Converter-Interfaced Renewable Energy Resources

Processes ◽

10.3390/pr8010034 ◽

2019 ◽

Vol 8 (1) ◽

pp. 34 ◽

Cited By ~ 1

Author(s):

Shijie Cui ◽

Peng Zeng ◽

Chunhe Song ◽

Zhongfeng Wang

Keyword(s):

Renewable Energy ◽

Low Voltage ◽

Short Circuit ◽

Renewable Energy Sources ◽

Distribution Network ◽

Distribution Networks ◽

Fault Current ◽

Fault Protection ◽

High Penetration ◽

Small Fault

With the decentralization of the electricity market and the plea for a carbon-neutral ecosystem, more and more distributed generation (DG) has been incorporated in the power distribution grid, which is then known as active distribution network (ADN). The addition of DGs causes numerous control and protection confronts to the traditional distribution network. For instance, two-way power flow, small fault current, persistent fluctuation of generation and demand, and uncertainty of renewable energy sources (RESs). These problems are more challenging when the distribution network hosts many converter-coupled DGs. Hence, the traditional protection schemes and relaying methods are inadequate to protect ADNs against short-circuit faults and disturbances. We propose a robust communication-assisted fault protection technique for safely operating ADNs with high penetration of converter-coupled DGs. The proposed technique is realizable by employing digital relays available in the recent market and it aims to protect low-voltage (LV) ADNs. It also includes secondary protection that can be enabled when the communication facility or protection equipment fails to operate. In addition, this study provides the detail configuration of the digital relay that enables the devised protection technique. Several enhancements are derived, as alternative technique for the traditional overcurrent protection approach, to detect small fault current and high-impedance fault (HIF). A number of simulations are performed with the complete model of a real ADN, in Shenyang, China, employing the PSCAD software platform. Various cases, fault types and locations are considered for verifying the efficacy of the devised technique and the enabling digital relay. The obtained simulation findings verify the proposed protection technique is effective and reliable in protecting ADNs against various fault types that can occur at different locations.

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Influence of FACTS Device Implementation on Performance of Distribution Network with Integrated Renewable Energy Sources

Energies ◽

10.3390/en13205516 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5516

Author(s):

Filip Relić ◽

Predrag Marić ◽

Hrvoje Glavaš ◽

Ivica Petrović

Keyword(s):

Renewable Energy ◽

Distribution System ◽

Low Voltage ◽

Flow Direction ◽

Renewable Energy Sources ◽

Distribution Network ◽

Distribution Networks ◽

Energy Sources ◽

Voltage Profile ◽

Facts Devices

In the modern power system, Flexible Alternating Current Transmission System (FACTS) devices are widely used. An increased share of the distributed generation (DG) and the development of microgrids change the power flows in the existing distribution networks as well as a conventional power flow direction from the transmission to the distribution network level which may affect the overall stability aspects. The paper shows the FACTS devices’ implementation influence on the performance of the distribution network with integrated renewable energy sources (RES) observing the aspects of the oscillatory stability and the low-voltage motor starting. The FACTS devices, in particular the static var compensators (SVC), have been allocated according to a novel algorithm proposed in the paper. The algorithm uses an iterative process to determine an optimal location for implementation and rating power of SVC considering active power losses minimization, improvement of the voltage profile and maximizing return of investment (ROI) of FACTS devices. Novel constraints—transformer station construction constraint, SVC industrial nominal power value constraint and the constraint of distribution system operator (DSO) economic willingness to investment in the distribution network development are considered in the proposed algorithm. The analysis has been performed on 20 kV rural distribution network model in DIgSILENT PowerFactory software.

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A Novel Three-Phase Power Flow Algorithm for the Evaluation of the Impact of Renewable Energy Sources and D-STATCOM Devices on Unbalanced Radial Distribution Networks

Energies ◽

10.3390/en14196152 ◽

2021 ◽

Vol 14 (19) ◽

pp. 6152

Author(s):

Raavi Satish ◽

Kanchapogu Vaisakh ◽

Almoataz Y. Abdelaziz ◽

Adel El-Shahat

Keyword(s):

Renewable Energy ◽

Radial Distribution ◽

Power Flow ◽

Renewable Energy Sources ◽

Distribution Networks ◽

Energy Sources ◽

Branch Number ◽

Three Phase ◽

Radial Distribution Networks ◽

The Impact

The impacts of the fast growth of renewable energy sources (RESs) and distribution static synchronous compensators (D-STATCOMs) on unbalanced radial distribution networks (URDNs) are analyzed with three-phase power flow algorithms (PFAs). As the URDNs are unbalanced, they can experience voltage unbalance (VU). This paper proposes a novel three-phase PFA for URDNs with multiple RES and D-STATCOM device integrations. The bus number matrix (BNM) and branch number matrix (BRNM) developed in this paper make the implementation of the proposed PFA simple. These matrices are developed to store the bus numbers and branch numbers of newly created sections of the URDN. Both PQ and PV modeling of RES and PV modeling of D-STATCOM devices are effectively integrated into the proposed three-phase PFA. The accuracy of the proposed PFA has been tested on the IEEE-13 bus URDN and the results are found to be accurate with the IEEE results. Several study examples have been conducted on the IEEE-13 bus and the IEEE-34 bus URDNs with multiple integrations of three-phase RESs and three-phase D-STATCOMs. Test results indicate that these integrations improve the voltage profile, reduce the power loss and reduce the severity of the VU.

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An Effective Bi-Stage Method for Renewable Energy Sources Integration into Unbalanced Distribution Systems Considering Uncertainty

Processes ◽

10.3390/pr9030471 ◽

2021 ◽

Vol 9 (3) ◽

pp. 471

Author(s):

Eman S. Ali ◽

Ragab A. El-Sehiemy ◽

Adel A. Abou El-Ela ◽

Karar Mahmoud ◽

Matti Lehtonen ◽

...

Keyword(s):

Renewable Energy ◽

Radial Distribution ◽

Distribution System ◽

Distribution Systems ◽

Optimization Problems ◽

Renewable Energy Sources ◽

Distribution Networks ◽

Test System ◽

Energy Sources ◽

The Impact

The output generations of renewable energy sources (RES) depend basically on climatic conditions, which are the main reason for their uncertain nature. As a result, the performance and security of distribution systems can be significantly worsened with high RES penetration. To address these issues, an analytical study was carried out by considering different penetration strategies for RES in the radial distribution system. Moreover, a bi-stage procedure was proposed for optimal planning of RES penetration. The first stage was concerned with calculating the optimal RES locations and sites. This stage aimed to minimize the voltage variations in the distribution system. In turn, the second stage was concerned with obtaining the optimal setting of the voltage control devices to improve the voltage profile. The multi-objective cat swarm optimization (MO-CSO) algorithm was proposed to solve the bi-stages optimization problems for enhancing the distribution system performance. Furthermore, the impact of the RES penetration level and their uncertainty on a distribution system voltage were studied. The proposed method was tested on the IEEE 34-bus unbalanced distribution test system, which was analyzed using backward/forward sweep power flow for unbalanced radial distribution systems. The proposed method provided satisfactory results for increasing the penetration level of RES in unbalanced distribution networks.

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