Power Loss Profile Research Articles

Economic Analysis of Hres Based Distributed Generation for Mitigation of Power Loss and Voltage Profile Problem

Economic Analysis of Hres Based Distributed Generation for Mitigation of Power Loss and Voltage Profile Problem

Power loss reduction and voltage enhancement via distributed photovoltaic generation: Case study in North Cyprus

Recently, power systems have witnessed a vast shift toward the integration of distributed generation systems (DGs), such as solar photovoltaic (PV) systems. The importance of planning DGs cannot be denied as they help to improve operations in the system and reduce the reliance on fossil fuel-based power generation methods. This paper proposes a new method for site and size selection of distributed PV systems considering system active power loss and nodal voltage profiles. The novelty of this work relies on nodal voltage magnitude deviations for PV siting and sizing criteria where PV DG sizes are weighted based on the voltage deviation index. This work includes a detailed case study performed on the Northern Cypriot power system with promising results that validate the proposed method against unweighted approaches.

Capacity‐basedoptimization using whale optimization technique of a power distribution network

AbstractIn the power distribution network, real power loss and voltage profile management are critical issues. By providing active and reactive power support, both of these issues can be managed. Distributed generation (DG) and capacitor bank (QG) can be utilized to solve these issues. Therefore, this paper utilized optimally placed and sized DG and capacitor (QG) to minimize losses and improve the voltage profile. The overall problem is optimized using an upgraded method of the fitness assignment and solution chasing based on the aggregate approach called multi‐objective whale optimization algorithm (MWOA). Wind and solar photovoltaic sources with biomass are utilized as the DG sources with their probabilistic outputs. The developed method is tested using two practical feeders of Bahir Dar city distribution network, Ethiopia. The results of loss minimization and voltage profile enhancement with MWOA are compared with multi‐objective particle swam optimization (MPSO) with an equal number of iterations to show the superiority of the developed method.

Electrothermal Stress Analysis and Lifetime Evaluation of DC-Link Capacitor Banks in the Railway Traction Drive System

In the railway traction drive system, the reliability of DC-link capacitor banks faces enormous challenges due to the multioperation conditions, the complex physical structures, and the safe operation requirements. Considering these issues, this article proposes a reliability evaluation method of the DC-link capacitors banks to provide a guideline for preventive maintenance in the traction drive system. In the electrothermal stress analysis, different from the conventional methods, the dynamic power loss profile is obtained by the sliding-window discrete Fourier transform (DFT), and the equivalent series resistance is fit by the neural network. Afterward, a bidirectional thermal model is established to estimate the thermal stress under the dynamic power losses, considering the impact of thermal capacity, thermal coupling, and air-cooling heat dissipation. In addition, according to the stability analysis and the rated temperature limitation, an end-of-lifetime standard that meets the safe operation requirement of the train is first proposed, thereby evaluating the lifetime bottleneck of the DC-link capacitor banks. The evaluation results can provide a reference to use the low-cost on-condition maintenance instead of scheduled maintenance in the railway traction drive system. Furthermore, a prototype experiment is performed to verify the effectiveness of the electrothermal stress model.

Cooperative negawatt P2P energy trading for low-voltage distribution networks

In this paper, the formation and feasibility of negawatt (nW) peer-to-peer (P2P) energy trading in a grid-connected energy network are studied. In particular, a framework is presented to introduce nW P2P trading concept in the local electricity market in order to provide cost savings to each participating prosumer. To capture the decision-making strategy of various nW prosumers, a coalition game model is proposed whereby prosumers can trade energy frequently in a collaborative way. The proposed nW P2P trading framework satisfies the beneficial criterion of the coalition game. Also, it confirms the stability and prosumer-focused feature of the structured coalition. To distribute the total coalition payoff between nW prosumers, Shapley value and Nucleolus are used. Finally, simulation results are provided to examine the effectiveness of the developed nW P2P trading on an actual distribution network. The simulation results emphasise that the proposed nW P2P trading can (1) enable prosumers to minimise notable portion of their electricity costs compared to the grid’s-facilitated demand response scheme, (2) keep total power loss and voltage profiles within permissible ranges, and (3) avoid network protection arrangements required for voltage regulation as opposed to kilowatt P2P trading.

A Novel Three-Pulse Equivalent Power Loss Profile for Simplified Thermal Estimation

One of the key challenges for long-term reliability analysis of power electronic converters is to quickly estimate extensive junction temperature cycles of power semiconductor devices while fulfilling an accepted accuracy. To address this challenge, this article proposes a novel three-pulse equivalent power loss profile. By contrast to the conventional methods of dividing the power loss equally, this article discretizes the power loss profile based on the identified occurrences of maximum and minimum junction temperatures (i.e., thermal characteristics). This proposed model decouples the conventional conflict between the thermal estimation accuracy and computational burdens. And it has the advantages of improving accuracy in terms of the maximum and minimum junction temperatures, and power-on time of thermal profiles, which are majorly concerned by today’s lifetime models of power semiconductors. Moreover, the proposed method also helps to reduce computational burdens. The relevant variables of the thermal modeling methods are investigated. Finally, the effectiveness of the proposed method is verified through simulation and experiments, and the impact of its thermal estimation advantages on lifetime evaluation is analyzed further.

Voltage Profile Enhancement and Loss Minimization Using Optimal Placement and Sizing of Distributed Generation in Reconfigured Network

Power loss and voltage instability are major problems in distribution systems. However, these problems are typically mitigated by efficient network reconfiguration, including the integration of distributed generation (DG) units in the distribution network. In this regard, the optimal placement and sizing of DGs are crucial. Otherwise, the network performance will be degraded. This study is conducted to optimally locate and sizing of DGs into a radial distribution network before and after reconfiguration. A multi-objective particle swarm optimization algorithm is utilized to determine the optimal placement and sizing of the DGs before and after reconfiguration of the radial network. An optimal network configuration with DG coordination in an active distribution network overcomes power losses, uplifts voltage profiles, and improves the system stability, reliability, and efficiency. For considering the actual power system scenarios, a penalty factor is also considered, this penalty factor plays a crucial role in the minimization of total power loss and voltage profile enhancement. The simulation results showed a significant improvement in the percentage power loss reduction (32% and 68.05% before and after reconfiguration, respectively) with the inclusion of DG units in the test system. Similarly, the minimum bus voltage of the system is improved by 4.9% and 6.53% before and after reconfiguration, respectively. The comparative study is performed, and the results showed the effectiveness of the proposed method in reducing the voltage deviation and power loss of the distribution system. The proposed algorithm is evaluated on the IEEE-33 bus radial distribution system, using MATLAB software.

Optimal Placement of Distribution Generation Sources in Hybrid Generation Network

The ideal places and size of the distribution generators were determined by reducing the loss of power in the distribution networks. The ideal positioning of various kinds of DGs has been suggested in the current job. In this job, the ideal power factor for DG supply has been acquired, both the active power as well as the reactive power. In the proposed approach, different types of distribution generation (DG) supply both reactive and real power. For the optimal placement of DG sources, particle swarm optimization techniques have been used in this job. Each of these innovations has its own strengths and drawbacks. Most of the methods that have been proposed so far to formulate DG’s optimum placement problem only consider Type-I DGs, Type-II and Type-III DGs that are considered for optimal position in the existing research. In the reference, artificial bee colony algorithm was used to determine sites of DGs and condenser combinations and optimal size. The author used PSO method in the reference to determine the appropriate positioning of the DG’s and to maximize the savings of power loss and voltage profile in the distribution network.

A High Efficiency and Low Cost ANPC Inverter Using Hybrid Si/SiC Switches

This paper presents a performance investigation and design optimization of a high efficiency three-level Active Neutral Point Clamped (ANPC) inverter topology using hybrid Si/SiC switches. It uses a modulation strategy that produces a cluster of low frequency switches commutating at fundamental line frequency (realized with Si IGBTs) and high frequency switches commutating at carrier frequency (realized with hybrid Si/SiC switches) to facilitate a tradeoff between the inverter efficiency and cost. A generalized Si/SiC current rating ratio optimization algorithm is presented for the hybrid Si/SiC switches based on the power loss profile of ANPC inverter. This algorithm determines the optimal current rating ratio between the Si IGBT and SiC MOSFET for the hybrid Si/SiC switches based on the inverter operating specification and Si/SiC gate control technique to achieve the best tradeoff between cost, loss and reliability. The performance of the proposed ANPC inverter system is investigated and compared with other similar ANPC inverter systems. The proposed ANPC inverter system achieves higher efficiency compared to an all Si IGBT based ANPC inverter system, all SiC MOSFET based ANPC inverter system, and other ANPC inverter systems consisting mixed Si IGBT and SiC MOSFET devices. On the other hand, the semiconductor device cost of the proposed ANPC inverter system is much lower than an all SiC MOSFET based ANPC inverter system and the mixed Si IGBT and SiC MOSFET based ANPC inverter systems while it is on par with an all Si IGBT based ANPC inverter system.

Optimal Energy Efficiency Tracking in the Energy-Stored Quasi-Z-Source Inverter

In this paper, the interaction between the energy storage (ES) power distribution and system efficiency enhancement is researched based on the energy stored quasi-Z-source inverter. The corresponding current counteraction, stress reduction, power loss profile, and efficiency enhancement around the embedded energy storage units are studied in details. Firstly, the current counteraction effect on the device current is presented with the embedded ES source. The corresponding reduction in the device current stress is revealed. Then, the detailed device power loss expressions with current redistribution in the impedance network are explored mathematically. A quasi-inverted-trapezoidal power loss profile is found with the embedded source power distribution. To further increase the overall system efficiency, an optimal energy efficiency tracking strategy is proposed for the ES-qZSI (energy-stored quasi-Z-source inverter) based on the power distribution control. Both the simulation and the experiment verified that the power loss is reduced by over 40% through the proposed efficiency enhancement method. The device current and loss analysis for the embedding of energy storage can also be extended to the operating range optimization in other ES systems.

Optimization of Demand Side Management and DG Placement in the Distribution System with Demand Response

In the distribution system, Distribution Generation (DG) plays an vital role and by optimizing the DG the performance and efficiency is improved in the distribution system network. Demand Side Management (DSM) deals with this process of optimizing the DGs in a network. In this paper, a new algorithm is proposed for optimal DSM including the demand response and DG units. The optimal capacity and location of the DGs to be connected in the network are selected using real and reactive power loss and voltage profile. The environmental conditions and economic operation of the system is ensured by optimizing the daily performance of the multiple DG units and grid parameters with and without inclusion of demand response. A non dominated sorting firefly algorithm is used to obtain optimization of the functions and decision making fuzzy system is used to decide the best possible scenario from the list of optimized solutions. It is tested with IEEE 33 bus system. The validity of the proposed DSM methodology is verified with the simulation results.

A finite time adaptive back‐stepping sliding mode control for instantaneous active‐reactive power dynamics based DFIG‐wind generation towards improved grid stability

AbstractIn this paper, a low computational, robust nonlinear feedback control is proposed as independent distributed generation controller (IDGC) for doubly fed induction generator (DFIG) based wind power generation system (WPGS). WPGS integration as distributed generation (DG) to grid point of common coupling (PCC) is reflecting high power loss profile in terms of low frequency oscillations under grid operational contingencies and have high instability hazard under unbounded uncertainties like unintentional islanding operation. Thus, to improve the stability margin of DFIG‐WPGS integration fast DG dynamic relations are obtained, where instantaneous active‐reactive power (P‐Q) formulation is proposed to avoid unnecessary phase locked loop (PLL) angle (ω) estimation. The feedback path is designed with proposed finite time adaptive backstepping sliding mode control (FTABSMC) for IDGC operation according to ISA‐95 standards. The FTABSMC is ensured with bounded/unbounded uncertainty handling capability by incorporating backstepping based dynamic error profile depletion and with enhanced stability margin by finite time sliding surface based error trajectory to equilibrium. Further, the adaptive sliding surface estimation is proposed in terms of dynamic uncertainty (energy fluctuation) for robust unbounded uncertainty handling. The stability improvement is established with small‐signal (SS) based closed loop analysis of considered DFIG‐WPGS. The uncertainty handling capability is presented thought rigorous case studies in MATLAB based simulation environment and TMS 320 digital signal processor (DSP) based processor‐in‐loop (PIL) validation.

ACTIVE POWER LOSS REDUCTION BY FLOWER POLLINATION ALGORITHM

This paper presents Flower Pollination (FP) algorithm for solving the optimal reactive power problem. Minimization of real power loss is taken as key intent. Flower pollination algorithm is a new nature-inspired algorithm, based on the characteristics of flowering plants. The biological evolution point of view, the objective of the flower pollination is the survival of the fittest and the optimal reproduction of plants in terms of numbers as well as the largely fittest. In order to evaluate the performance of the proposed Flower Pollination (FP) algorithm, it has been tested on IEEE 57 bus system and compared to other standard reported algorithms. Simulation results show that FP algorithm is better than other algorithms in reducing the real power loss and voltage profiles are within the limits.

Continuous domain ant colony optimization for distributed generation placement and losses minimization

This paper proposes a method for distributed generation (DG) placement in distribution system for losses minimization and voltage profile improvement. An IEEE 33-bus radial distribution system is used as the test system for the placement of DG. To facilitate the sizing of DG capacity, a meta-heuristic algorithm known as Continuous Domain Ant Colony Optimization (ACO<sub>R</sub>) is implemented. The ACO<sub>R</sub> is a modified version of the traditional ACO which was developed specially for solving continuous domain optimization problem like sizing a set of variables. The objective of this paper is to determine the optimal size and location of DG for power loss minimization and voltage profile mitigation. Three case studies were conducted for the purpose of verification. It was observed that the proposed technique is able to give satisfactory results of real power loss and voltage profile at post-optimization condition. Experiment under various loadings of the test system further justifies the objective of the study.

Optimal Placement and Sizing of Distributed Generation in Distribution System using Analytical Method

The reliability of distribution network can be improved with the penetration of small scale distributed generation (DG) unit to the distribution grid. Nevertheless, the location and sizing of the DG in the distribution network have always become a topic of debate. This problem arises as different capacity of DG at various location can affect the performance of the entire system. The main objective of this study is to recommend a suitable size of DG to be placed at the most appropriate location for better voltage profile and minimum power loss. Therefore, this paper presents an analytical approach with a fixed DG step size of 500 kW up to 4500 kW DG to analyses the effect of a single P-type DG in IEEE 33 bus system with consideration of system power loss and voltage profile. Four scenarios have been selected for discussions where Scenario 1: 3500 kW DG placed at node 3; Scenario 2: 2500 kW DG placed at node 6; Scenario 3: 1000 kW DG placed at node 18 and Scenario 4: 3000 kW DG placed at node 7. Results show that all the four scenarios are able to reduce the power loss and improve the voltage profile however Scenario 4 has better performance where it complies with minimum voltage requirement and minimizing the system power loss.

Optimal power flow studies in direct current grids: An application of the bio-inspired elephant swarm water search algorithm

Colombian power system is experienced important changes due to the large scale integration of renewable power generation based on solar and wind power; added to the fact that direct current networks have taken important attention, since they are efficient in terms of power loss and voltage profile at distribution or transmission levels For addressing this problem, this paper presents the application of an emerging bio-inspired metaheuristic optimization technique known as elephant swarm water search algorithm to the optimal power flow problem in direct current networks. A master-slave hybrid optimization strategy for optimal power flow analysis is addressed in this paper by decoupling this problem in two optimizing issues. The first problem corresponds to the selection of the power generated by all non-voltage controlled distributed generators; While the second problem lies in the solution of the classical power flow equations in direct current networks. The solution of the master problem (first problem) is made by applying the elephant swarm water search algorithm, while the second problem (slave problem) is solved by a conventional Gauss-Seidel numerical method. The proposed hybrid methodology allows solving the power flow problem by using any basic programming language with minimum computational effort and well-precision when is compared with optimizing packages such as general algebraic modeling system/CONOPT solver and conventional metaheuristic techniques such as genetic algorithms.

Voltage Control and Power Loss Reduction in Distribution Networks using Distributed Generation

Distributed generation (DG) units can provide many benefits when they are incorporated along the distribution network/system. These benefits are more if DG units are connected at suitable nodes with appropriate rating otherwise, they may cause to increased power loss and poor voltage profile. In this work, optimal allocation (both location and size) problem is solved by considering power loss minimization as an objective function. An analytical method “index vector method (IVM)” is applied to find DG location. A new optimization algorithm “Whale Optimization Algorithm (WOA)” is employed to determine the DG rating. Two popularly known test systems “IEEE 33 & IEEE 69”bus systems are used to evaluate the efficacy of IVM and WOA.

Optimal sitting and sizing of shunt capacitor for real power loss reduction on radial distribution system using firefly algorithm: A case study of Nigerian system

ABSTRACT Geometrical increase in power demand and high load density at the distribution ends of modern power systems have key consequential problems of high power loss and poor voltage profile, as a result of which the integrity of radial distribution networks to faithfully account for the energy received from transmission subsystems has been seriously undermined. This challenge is, however, being overcome by placement of shunt capacitors to supply the reactive power required for compensation; hence, optimal sitting and sizing of compensators has been intensively researched. As efficient as the use of meta-heuristic algorithms for joint optimal placement and sizing of the shunt capacitors are, employment of the approach on the Nigerian radial distribution system (RDS) is not yet popular as most of the earlier works reported rather used analytical and numerical programming approaches. In this study, therefore, the use of firefly algorithm (FA) on a Nigerian 11-kV feeder is presented as an approach to optimally site and size shunt capacitor for real power loss reduction on such network. Backward-forward sweep load flow technique, with voltage stability index (VSI), is employed to find the candidate buses where the shunt capacitors would be installed, then FA is employed to determine the optimal size required. This approach is implemented on a 34-bus 11-kV feeder and it is found out that the system’s real power loss reduced from 762.6419 to 597.7486 kW, while the minimum bus voltage magnitude was raised from 0.8295 to 0.8456 p.u. and the minimum system VSI was improved from 0.4741 to 0.5121 p.u. Based on these results, the proposed approach is, therefore, considered a promising technique for sitting and sizing shunt capacitor optimally in real practical RDS.

A Simplification Method for Power Device Thermal Modeling With Quantitative Error Analysis

To evaluate the reliability of power electronic systems, it is necessary to estimate the junction temperatures of power devices under periodic power loss profiles due to the fundamental-frequency current. However, a large number of periodic power loss profiles under long-term reliability evaluation (e.g., 1 year) are challenging to compute quickly. On the other hand, in order to improve computational efficiency, unvalidated simplified thermal analysis methods may impair the confidence of the reliability outcome. Therefore, this paper proposes an analytical model for power semiconductors with a compromise of the thermal estimation accuracy and computational efficiency. With the proposed model, it is indicated that minimum computation efforts can be obtained for thermal estimation under a maximum allowable error. The proposed method, thus, enables computation-efficient thermal stress analysis for power semiconductor devices with a preset modeling error. The effectiveness of the proposed method has been verified by simulations and experiments on a power electronic system with 1200-V/50-A insulated gate bipolar transistor (IGBT) modules.

Modified JAYA algorithm for optimal power flow incorporating renewable energy sources considering the cost, emission, power loss and voltage profile improvement

This paper presents a new version of JAYA algorithm to solve the problem of optimal power flow (OPF) incorporating renewable energy sources (RES) with four different objective functions that reflect fuel cost minimization, emission minimization, transmission power loss minimization, and voltage profile improvement. The proposed modified JAYA (MJAYA) algorithm can be derived by modifying the equation that used to update the solutions based on best and worst solutions. The formulation of the OPF problem incorporating RES with four different objective functions is introduced in this paper. Then, the proposed MJAYA is employed to solve this problem by converting it into a single objective function using price and weighting parameters. In addition, the scalability of the proposed MJAYA is tested. To prove the effectiveness of the proposed MJAYA algorithm, it is applied to two different test systems (IEEE 30-bus system and IEEE 118-bus system). The obtained results of different scenarios using the proposed MJAYA algorithm are compared with those obtained using other published methods in the literature. The comparisons with other published methods show the superiority of the proposed MJAYA algorithm over other methods with different complexities.