Multi-source distribution network fault elimination strategy based on real-time risk perception

Renewable energy driven distributed generators (DGs) are mostly connected to radial distribution network with overhead feeders. It is estimated that 80% of network faults are temporary single phase to ground faults and therefore automatic restoration is required. A combination of automatic re-closer devices, circuit breaker, sectionalizer and fuse is applied to clear the temporary fault and isolate the permanent fault in order to optimise the service continuity to customers. Investigation into the sustainability of different DG technologies during temporary faults on overhead network should be carried out to (i) assess the possibility of preserving DG in services as far as possible to optimise the electric supply continuity and (ii) identify the requirements of automatic restoration in distribution networks with high penetration of DGs. On the other hand, it has been reported that future distribution networks are very likely to be operated in ring mode in order to maximise the installed capacity of distributed generation. The ring network operation mode will need special considerations in network feeder protection compared to radial network operation mode in the context of DG. Thus the implementation of auto reclosing in ring network with DG will also need further investigation. This paper reports an investigation into the impact of different wind power based distributed generations on auto reclosing schemes in MV overhead distribution networks that are operated in radial and ring modes. The paper is divided into two parts; the first part present literature survey on the development of system protection schemes in power distribution network with high penetration of DG. The second part present results of dynamic simulation studies on the operation of auto reclosing scheme in network with DGs when operated in different operating modes. A particular emphasis is placed on examining the application of single pole auto reclosing scheme in the distribution network.

With the rapid development of power system, the distribution network structure is gradually mature and the connection situation is more complex. The traditional distribution network reliability calculation method can not accurately calculate the reliability index of complex distribution network. Based on the traditional simple power supply reliability evaluation method of radial distribution network, this paper completely considers the influence of circuit breaker, tie switch, branch line, standby transformer and other equipment, and puts forward an improved network equivalence method model. The model first treats the complex distribution system in layers, and then gradually equates it into a simple radial distribution network to calculate the reliability of the system. At the same time, this paper analyzes the distribution network with multi connection structure in a provincial capital city. The results show that this model simplifies the complexity of distribution system reliability calculation, improves the accuracy and speed of reliability calculation, and more truly reflects the reliability of actual distribution system.

The rapid depletion of fossil fuel motivates researchers and policymakers to switch from the internal combustion engine (ICE) to plug-in electric vehicles (PEVs). However, the electric power distribution networks are congested, which lowers the accommodation of PEVs and produces higher power losses. Therefore, the study proposes an effective deterministic methodology to maximize the accommodation of PEVs and percentage power loss reduction (%PLR) in radial distribution networks (RDNs). In the first stage, the PEVs are allocated to the best bus, which is chosen based on the loading capacity to power loss index (LCPLI), and the accommodation profile of PEVs is developed based on varying states of charge (SoC) and battery capacities (BCs). In the second stage, the power losses are minimized in PEV integrated networks with the allocation of DG units using a recently developed parallel-operated arithmetic optimization algorithm salp swarm algorithm (AOASSA). In the third stage, the charging and discharging ratios of PEVs are optimized analytically to minimize power losses after planning PEVs and DGs. The outcomes reveal that bus-2 is the most optimal bus for accommodation of PEVs, as it has the highest level of LCPLI, which is 9.81 in the 33-bus system and 28.24 in the 69-bus system. The optimal bus can safely accommodate the largest number of electric vehicles, with a capacity of 31,988 units in the 33-bus system and 92,519 units in the 69-bus system. Additionally, the parallel-operated AOASSA mechanism leads to a reduction in power losses of at least 0.09% and 0.25% compared with other algorithms that have been previously applied to the 33-bus and 69-bus systems, respectively. Moreover, with an optimal charging and discharging ratio of PEVs in the IEEE-33-bus radial distribution network (RDN), the %PLR further improved by 3.08%, 4.19%, and 2.29% in the presence of the optimal allocation of one, two and three DG units, respectively. In the IEEE-69-bus RDN, the %PLR further improved by 0.09%, 0.09%, and 0.08% with optimal charge and discharge ratios in the presence of one, two, and three DG units, respectively. The proposed study intends to help the local power distribution companies to maximize accommodation of PEV units and minimize power losses in RDNs.

Distributed energy resources (DERs) provide various benefits to distribution networks, including the enhancement of reliability, resilience, sustainability, security, energy efficiency, and deferral of capacity upgrades, where each benefit should be valued individually. Accordingly, DER valuation which corresponds with its stated objective in a distribution network is viewed as a challenging task in electric power systems. This paper presents a method to calculate the valuable portion of installed DERs regarding their contribution to the network capacity upgrade deferral. The proposed approach will assign priority-based marginal values to existing DER locations in a distribution network and calculates the corresponding DER amounts for the deferral of capacity upgrades, which is based on respective locational marginal values. The proposed method utilizes the DistFlow method for DER valuation that considers branch flow constraints in radial distribution networks. The IEEE 33 and the modified IEEE 123 node distribution networks are studied in which several scenarios are analyzed to demonstrate the merits of the proposed method. The results provide additional insights on distribution networked-constrained DER valuation and demonstrate that the DER valuation can provide an alternative for deferring capacity upgrades economically in a distribution network.

Most of the generated electricity is lost in power loss while transmitting and distributing it to the consumer end. The power losses occurring in the distribution network cause deviation in voltage and lower stability due to increased load demand. The integration of multiple Distributed Generation (DG) will enable the existing radial electrical distribution network efficient by minimizing the power losses and improving the voltage profile. Metaheuristic optimization techniques provide a favorable solution for optimal location and sizing of DG in the distribution network. A novel modern metaheuristic Transient Search Optimization (TSO) algorithm, inspired by the electrical network’s transient response of storage components implemented in the proposed work. The TSO formulated optimal DGs allocation to minimize total active power loss, voltage deviation and enhance voltage stability index as minimization optimization problem satisfying various equality and inequality constraints. The installation of multiple DG units at unity, fixed, and optimal power factors were examined. The TSO algorithm’s effectiveness was tested on standard IEEE 33-bus and 69-bus radial distribution networks, including various operating events developed in the form of single and multi-objective fitness functions. The active power loss reduced to 94.29 and 94.71% for IEEE 33 and 69 bus distribution systems. The obtained results trustworthiness is confirmed by comparison with well-known optimization methods like Genetic Algorithm (GA), Particle Swarm Optimization (PSO), combined GA/PSO, Teaching Learning Based Algorithm (TLBO), Swine influenza model-based optimization with quarantine (SIMBO-Q), Multi-Objective Harris Hawks optimizer (MOHHO) and other provided in the literature. The presented numerical studies represent the usefulness and out-performance of the proposed TSO algorithm due to its exploration and exploitation optimization mechanisms for the DG allocation problem meticulously.

This paper proposes a hybrid HS–DE algorithm-based optimal node identification and sizing of shunt capacitors with an aim to enhance the performance of the radial distribution network. To enhance the exploitation power of harmony search algorithm (HSA), differential evolution algorithm (DE) is embedded with it. The combination of sensitivity analysis and hybrid HS–DE algorithm is used to trace the optimal solution for the installation of shunt capacitive compensation. A comprehensive objective function is formulated to minimize real power loss, improve the voltage stability and voltage profile of the distribution network. The suitability of the proposed hybrid HS–DE-based approach has been validated using IEEE 69 node radial distribution test network at three discrete load scenarios, and the result outcomes are compared with HSA, DE and other similar methods in the literature. The simulation results reflect the superiority and robustness of the hybrid HS–DE-based approach for solving shunt capacitor planning problem in radial distribution networks.

When a single phase earth fault occurs in distribution network, the difference between the transient zero-sequence currents at the head of the non-faulty section before the fault point is small, and the non-faulty section after the fault point also has this feature, but the difference between the zero-sequence currents at the head of the section before and after the fault point is big. Based on this, a method for comparing the single-phase grounding fault section location in distribution network based on the difference of the transient zero-sequence current was proposed. Based on the known distribution network structure, the fault section table was compiled, then the transient zero-sequence currents difference at the head of each section were compared, the fault section could be selected. The simulation by PSCAD/EMTDC verified the reliability of the method.

In the present work, a strategic multi-scenario EV ultra-fast charging station (CS) planning framework is designed to provide advantages to charging station owners, Distribution Network Operators, and EV owners. Locations of CSs are identified using zonal division and the Voltage Stability Index strategy. The number of chargers is determined using the Harris Hawk Optimization (HHO) technique while minimizing the installation, operational costs of CS, and energy loss costs considering all the power system security constraints. To ensure a realistic planning model, uncertainties in EV charging behavior and electricity prices are managed through the 2m-Point Estimate Method. This method produces multiple scenarios of uncertain parameters, which effectively represent the actual dataset, thereby facilitating comprehensive multi-scenario planning. This study incorporates annual EV and system load growth in a long-term planning model of ten years, ensuring the distribution network meets future demand for sustainable transportation infrastructure. The proposed research work is tested on a 33-bus distribution network and a 51-bus real Indian distribution network. To evaluate the financial and environmental benefits of the planning, a cost-benefit analysis in terms of the Return-on-Investment index and a carbon emission analysis are performed, respectively. Furthermore, to prove the efficacy of the HHO technique, the results are compared with several existing algorithms.

This paper proposes the performance improvement of radial distribution network with distributed generation (DG) integration using extended particle swarm optimization (PSO) algorithm. High-performance distribution network is a network that has a low power loss, better voltage profile, and loading balance among feeders. The effort to improve the performance of the distribution network is network configuration optimization. The optimization has become an important issue with the presence of DG in distribution networks. In this study, network configuration optimization is based on an extended PSO algorithm. The methodology has been tested in two models of IEEE radial distribution networks. The results showed that the optimal configuration of the distribution network is able to reduce power loss and to improve the voltage profile of the network significantly.

Shunt capacitor placement in radial distribution networks considering switching transients decision making approach

We consider the problem of quantifying and assessing the steady-state voltage stability in radial distribution networks. Our approach to the voltage stability problem is based on a local, approximate, and yet highly accurate characterization of the determinant of the Jacobian of the power flow equations parameterized according to the branch-flow model. The proposed determinant approximation allows us to construct a voltage stability index that can be computed in a fully distributed or in a hierarchical fashion, resulting in a scalable approach to the assessment of steady-state voltage stability. Finally, we provide upper bounds for the approximation error and we numerically validate the quality and the robustness of the proposed approximation with the IEEE 123-bus test feeder.

The presence of wind power, photovoltaic, and other distributed energy sources within the distribution network. The power quality of the distribution network degrades as the proportion of distributed energy increases. To address the uncertainty introduced by the integration of distributed energy, it is essential to coordinate and optimize the multi-voltage levels within the distribution network. Currently, most studies focus on achieving voltage control in the distribution network by minimizing either network loss or voltage fluctuation, often limiting consideration to a single voltage stage. Minimizing network loss can enhance the overall operational cost efficiency of the distribution network, but it has a limited impact on suppressing voltage fluctuation. Hence, this paper initially establishes a two-layer voltage control model for the distribution network through priority target programming. The first layer employs the minimum voltage deviation as the objective function to meet the 10-0.38 kV voltage control requirements. The second layer minimizes the total operational cost of the distribution network, incorporating network loss costs as the objective function to meet economic operational requirements. The programming is subsequently implemented in GAMS. Lastly, the effectiveness of the proposed model is validated using the IEEE-33 node system.

Faults in the power system cause inconvenience in the transmission and distribution networks. Faulty conditions occur due to many reasons both internally and externally. Lightning strikes, cyclones, overheating, fire dangers, destruction of electrical devices, failure of power system components owing to deteriorated equipment, and human errors are only a few of the reasons. These faults in the power distribution network are unpredictable and can cause a reduction in system reliability that can result in exorbitant repairs, loss of productivity, blackout to customers, and even loss of life. The paper does not address any detection methods, but a study of the simulation of symmetrical fault, asymmetrical fault, load switching, capacitor switching, and high impedance faults in the radial distribution network and the analysis is done in Matlab/SIMULINK 2020. The waveforms obtained during single line to ground fault, the line-to-line fault, double line to ground fault, the triple line to ground fault, high impedance fault, load switching, and capacitor switching are presented.

Comprehensive coordination of radial distribution network protection in the presence of synchronous distributed generation using fault current limiter

With the rapid development of intelligent distribution network, a large number of distributed generation (DG) penetrated into the distribution network, changing the original unidirectional current flow direction of the distribution network, which made the direction of the flow is bidirectional or multi-end flow. When a fault occurs, the traditional centralized feeder automation and in-situ feeder automation solutions have not been able to satisfy fast accuracy requirements and have presented severe challenges to fault self-healing. In view of the existing problems, a control method based on quick-acting faults distributed FA is researched. It uses stacked topology recognition. After detecting current and interacting with the peer-to-peer through GOOSE communication, the smart terminal determines the fault area and jump on the local monitoring switch on the spot. After the fault is isolated, the power supply recovery operation is initiated. Taking a typical distributed power distribution network as an example, the different faults are studied. The experimental finally results show that the scheme can adapt to faults in various situations, and the entire fault self-healing process is controlled within 200 ms.