Active Power Quality Research Articles

Analysis of Improvements to Bank Capacitor Requirements in 20kv Voltage Distribution Network Panels for Power Plant 2 at PT. Toyota Motor Manufacturing Indonesia

This research aims to describe and analyze the effectiveness of using capacitor bank capacity in PT's power plant 2 distribution system. TMMIN. The focus is to analyze the initial design of capacitor bank requirements for each panel in the substation production line, including Painting, Assembly and Welding, to increase capacitor bank requirements according to electrical theory standards. The Power Factor calculation method is used to measure the required capacitor bank capacity. The power factor is influenced by the type of electrical load which is resistive, inductive or capacitive, with a value range between 0 and 1. A power factor close to 1 indicates high active power and better electrical power quality, while a power factor close to 0 indicates high reactive power. reducing power quality and increasing electrical energy use. The current power factor value is obtained from the actual voltage and active power conditions, and the required capacitor bank value is calculated with a target power factor of 0.9 or 0.95. According to calculations, the panels that can be repaired are panels 3, 4, 5, 6 Painting, panel 1 Assembly, and panel 1 Welding. The results show that 2 MDB panels reach ideal conditions with 6 steps of 2x50kVAR capacitor bank, while the other 6 MDB panels require an additional 2 steps of 2x50kVAR capacitor bank to achieve ideal conditions.

Voltage and Reactive Power-Optimization Model for Active Distribution Networks Based on Second-Order Cone Algorithm

To address the challenges associated with wind power integration, this paper analyzes the impact of distributed renewable energy on the voltage of the distribution network. Taking into account the fast control of photovoltaic inverters and the unique characteristics of photovoltaic arrays, we establish an active distribution network voltage reactive power-optimization model for planning the active distribution network. The model involves solving the original non-convex and non-linear power-flow-optimization problem. By introducing the second-order cone relaxation algorithm, we transform the model into a second-order cone programming model, making it easier to solve and yielding good results. The optimized parameters are then applied to the IEEE 33-node distribution system, where the phase angle of the node voltage is adjusted to optimize the reactive power of the entire power system, thereby demonstrating the effectiveness of utilizing a second-order cone programming algorithm for reactive power optimization in a comprehensive manner. Subsequently, active distribution network power quality control is implemented, resulting in a reduction in network loss from 0.41 MW to 0.02 MW. This reduces power loss rates, increases utilization efficiency by approximately 94%, optimizes power quality management, and ensures that users receive high-quality electrical energy.

System Power Quality Analysis under Wind–Hydro Complementary Generation Mode

The highly random and characteristics of wind power generation challenge the power quality of the wind–hydro complementary generation system (WHCGS). Herein, the transient characteristics of power quality under the complementary generating mode are studied. First, a nonlinear hydropower system (HPS) model is innovatively established considering the dynamic characteristics of hydrounits under part load operation, and then a wind power system model including wind speed model, wind turbine and its controller, generator and converter is established. Finally, the applicability of WHCGS model in power quality evaluation is established and verified by IEEE‐9 node model. Combined with active power, frequency, and voltage power quality indicators, the effects of wind–hydro capacity ratio and voltage sag on the system are quantified. The results show that the increase in wind power penetration will deteriorate the power quality of WHCGS. Moreover, when the wind power capacity reaches 60 MW, it will damage the voltage and frequency stability of HPS. Besides, the larger the voltage sag amplitude, the worse the power quality of WHCGS. The longer the voltage sag lasts, the higher the risk of WHCGS instability. This article provides a technical reference for the safe and stable operation of WHCGS.

Improvement of hybrid grid-connected inverter control scheme with active power injection and power quality improvement in order to operate in weak grid conditions

Improvement of hybrid grid-connected inverter control scheme with active power injection and power quality improvement in order to operate in weak grid conditions

Power Selective Control With Fault Tolerance of Multifunctional Inverter for Active Power Injection and Power Quality Compensation

This paper proposes a power selective control with fault tolerance of multifunctional inverter for active power injection and power quality compensation. The multifunctional inverter is widely researched, because the inverter capacity can be fully used to realize multiple functions. However, the inverter legs may have open-circuit fault during operation, affecting the realization of inverter functions and even causing the secondary fault. Following the early stage of fault detections, fault tolerance can be applied to inverters, in some cases, to prevent unexpected shutdowns. The fault tolerance control enables the inverter to be reconstructed to another steady state and operates normally under open-circuit fault. By reconstructing of the inverter, the non-faulty legs can prioritize and selectively inject active, reactive, and harmonic power, so as to realize the multifunction during the leg open-circuit fault. Finally, the simulation and experimental results are given to demonstrate the effectiveness of proposed power selective control with fault tolerance of multifunctional inverter for active power injection and power quality management.

A Residential Miniboost Photovoltaic Inverter With Maximum Power Point Operation and Power Quality Compensation

Among the exiting multifunctional photovoltaic (PV) inverters (MPVIs), the main challenges are low efficiency, undesired harmonic emission, and weak compensation capability. In this paper, a theoretical study via rotating phasor to the PV curves is firstly proposed to figure out the undesired harmonic emission puzzle in different PV inverters as well as to provide the foundation for PV inverters to achieve multifunction ability under varying load conditions. On the other hand, a single-phase time-sharing miniboost MPVI with different operation modes is proposed and operated under varying PV and load conditions in order to improve its efficiency and compensation capability without undesired harmonic emission. Corresponding control strategy and stability analysis are given. Finally, a 1.5-kW prototype is presented, benchmarked against harmonic emission issues, compensation capability, and efficiency. Experimental results clearly indicate that the proposed topology and control method can perform the active power injection and power quality compensation with better efficiency and avoiding harmonic emission into the grid dynamically.

Quadratic Sensitivity Models for Flexible Power Quality Improvement in AC Electrified Railways

With the development of flexible traction power systems (TPSs), more active and flexible power quality improvement is becoming feasible for ac electrified railways. However, the standard definitions of power quality indexes of electrified railways are strongly nonlinear, which poses challenges to the optimal real-time power quality control of flexible TPSs. Therefore, this letter establishes universal and concise mathematical models that directly link the active and reactive power outputs of the traction transformer to the negative sequence current (NSC) and effective power factor (EPF) of traction substations (TSSs). With that, the quadratic sensitivity models (QSMs) of the power outputs of the traction transformer to the NSC and EPF of TSSs are developed. These QSMs can accurately estimate the varieties of NSC and EPF with the varieties of the power outputs of the traction transformer. To demonstrate their utility, two application schemes of the proposed QSMs for optimal real-time power quality control in flexible TPSs are explored and verified via hardware-in-the-loop experiments.

Active Power Filters and Power Quality

The transmission of electricity from the source to the load is mainly carried out using a three-phase line [...]

A Residual-Generator-Based Plug-and-Play Control Scheme Toward Enhancing Power Quality in AC Microgrids

In this article, an active power quality control scheme centered on an observer-based residual generator is proposed for power quality improvement in ac microgrids. The active power quality controller is realized by a plug-and-play (PnP) configuration and consists of three parts: the control of the power electronic converter, the flexible structure, and the optimization algorithm. By means of the observer-based realization of the Youla parameterization of a stabilizing controller, the active power quality controller with the PnP flexible structure is designed. The proposed active controller has the advantage of improving power quality without changing the structure or parameters of the original controller. The optimization of the controller is implemented by tuning the Youla parameterization system in the PnP flexible structure. Here, a gradient descent optimizing algorithm is applied to estimate the optimal tuning/control parameters online. Finally, extensive hardware-in-the-loop experiments and simulations are given to demonstrate the effectiveness of the proposed power quality controller.

Treating the Impacts of Connecting HVDC Link Converters with AC Power System Using Real-Time Active Power Quality Unit

The High Voltage Direct Current (HVDC) systems have been applied worldwide, due to important roles, technical benefits, and high efficiency. Usually, the HVDC network is a joining link between two separate and different technical properties of HVAC systems, which enhances its use. The joinpoint system that used to connect HVDC and HVAC links is a controlled converter circuit. Despite the importance of use and the significant benefits of the HVDC link, there are negative effects on the power quality of the electrical power of both systems connected on both ends of the HVDC network. The low quality of electric power has been addressed by known methods, whether traditional or modern. But the improvement is usually made with the assumption of load conditions and the need for the system to synthesize it. This research presents an innovative method based on real-time control strategy. This is performed by proposing dSPACE for controlling the Active Power Quality Unit (APQU). The proposed control strategy of the APQU includes a Modified Harmonics Pulse Width Modulation (MHPWM) algorithm in order to mitigate the line current THD and improve the effective power factor of the AC converter sides. The MHPWM is applicable for different nonlinear loads and can be implemented with APQU based on different topologies of H-bridge voltage source inverter. Simulation and practical results have been presented in this paper. The Experimental results are done based on real-time laboratory tests using dSPACE DS1103 board as a controller circuit. The presented results, under different operating loading conditions, show that the APQU provides almost unity power factor and significantly improving THD of the AC supply currents at both sides of the HVDC link controlled converters.

Hybrid compensation method for traction power quality compensators in electrified railway power supply system

In order to improve the Power Quality (PQ) of traction power supply system and reduce the power rating and operation cost of compensator, a Static VAR Compensator (SVC) integrated Railway Power Conditioner (RPC) is presented in this paper. RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network. The next generation of this equipment is Active Power Quality Compensator (APQC). The major concern of these compensators is their high kVA rating. In this paper, a hybrid technique is proposed to solve aforementioned problems. A combination of SVC as an auxiliary device is employed together with the main compensators, i.e., RPC and APQC that leads on to the reduction of power rating of the main compensators. The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system. The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents. The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents. In this paper firstly, the PQ compensation procedure in AC electrified railway is analyzed step by step. Then, the control strategies for SVC and the main compensators are presented. Finally, a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.

Power quality monitoring system based on IEC61850

Power quality monitoring system is an important means to find and evaluate power quality problems in time. A service-oriented browser / server (B / S) mode active power quality real-time monitoring system is designed and implemented, which provides the real-time monitoring function of power quality in the process of active power distribution network absorbing distributed power generation layer by layer, and focuses on observing the impact of the change of power flow direction on the level of power quality. Based on IEC 61850 standard, the system establishes the power quality information model, and uploads the real-time monitoring data of power quality on site to the master station for analysis and storage in the real-time database through MMS. The client communicates with the server through windows communication base (WCF) service to obtain real-time monitoring data, and realizes the global real-time monitoring function of power quality of active distribution network combined with the main wiring diagram, so as to achieve the integrated display effect of data graph.

Performance of Distribution Grid Connected Solar Photovoltaic Array with Unified Power Quality Conditioner

The control of distribution grid connected Solar Photovoltaic Array with Unified Power Quality Conditioner (SPV-UPQC) is presented. The SPV-UPQC comprises of a solar photovoltaic array, a shunt active power filter (APF) and series APF. In UPQC, the series and shunt Active Power Filters (APFs are connected in back to back with a common DC-bus capacitor. The shunt active compensator is used to extracts the power from solar PV array as well as compensates load current harmonics. The Synchronous Reference Frame (SRF) based control theory is used in shunt active compensator for extracting fundamental load active current component. The Unit Vector Template (UVT) technique is used in series active compensator. The series active compensator mitigates grid voltage sags and swells conditions by injecting voltage in phase or out of phase at the Point of Common Coupling (PCC) respectively. The proposed system performs both the transfer of active power and power quality enhancement simultaneously. The performance of the test system are examined under steady-state condition, grid voltage fluctuations and varying solar irradiation conditions by detailed simulation in MATLAB/Simulink software.

Dual-loop generalized predictive control method for two-phase three-wire railway active power quality controller

One of the most challenging topics in electric railway networks (ERNs) is power quality (PQ) problems caused by single-phase feeding of time-varying and high-power locomotives. During previous years, many techniques and compensators have been offered to alleviate these problems. Railway active power quality controller (RAPQC) is considered as one of the most efficient approaches. Due to the time-variant, uncertainty and distorted features of ERNs, the controlling of RAPQCs has always been a substantial concern to experts. This paper presents, a new robust control system for two-phase three-wire RAPQC (ThRAPQC) based on generalized model predictive control integrated with modified instantaneous reactive power theory (GMPC-MIRP). A dual-loop balancing system has been adopted in the proposed control system to equalize the active powers of traction power substation (TPSS) adjacent feeders, compensate reactive powers and suppress harmonic simultaneously. The performance of the proposed method in comparison with the conventional Fryze-Buchholz-Depenbrock (FBD)-based current strategy together with hysteresis current controller (FBD-HCC) has been evaluated through the detailed simulations and Opal-RT 5600-based laboratory setup results. The fast response, high precision, lower fluctuation in reference current tracking and high capability of working in distorted conditions are the outstanding privileges of the proposed method that are confirmed by the output results.

Multiple Spatiotemporal Characteristics-Based Zonal Voltage Control for High Penetrated PVs in Active Distribution Networks

The penetration of photovoltaic (PV) outputs brings great challenges to optimal operation of active distribution networks (ADNs), especially leading to more serious overvoltage problems. This study proposes a zonal voltage control scheme based on multiple spatiotemporal characteristics for highly penetrated PVs in ADNs. In the spatial domain, a community detection algorithm using a reactive/ active power quality function was introduced to partition an ADN into sub-networks. In the time domain, short-term zonal scheduling (SZS) with 1 h granularity was drawn up based on a cluster. The objective was to minimize the supported reactive power and the curtailed active power in reactive and active power sub-networks. Additionally, a real-time zonal voltage control scheme (RZVC) with 1 min granularity was proposed to correct the SZS rapidly by choosing and controlling the key PV inverter to regulate the supported reactive power and the curtailed active power of the inverters to prevent the overvoltage in each sub-network. With the time domain cooperation, the proposed method could achieve economic control and avoid overvoltage caused by errors in the forecast data of the PVs. For the spatial domain, zonal scheduling and zonal voltage control were carried out in each cluster, and the short-term scheduling and voltage controlling problem of the ADN could then be decomposed into several sub-problems. This could simplify the optimization and control which can reduce the computing time. Finally, an actual 10kV, 103-node network in Zhejiang Province of China is employed to verify the effectiveness and feasibility of the proposed approach.

Active power quality management in smart microgrids

In this manuscript, a new concept of active power quality management (APQM) is presented. In which, instead of solely controlling the nodal power quality in a power system, the power quality is seen as a network-level issue and a high-level management method to deal with this issue in distribution networks is presented. Analogous to how active network management enables increased levels of hosting capacity for interconnection of distributed energy resources (DERs) by managing thermal and voltage constraints, APQM maps consumer requirements and technical and regulatory standards to specific areas and actively manages operational power quality limits, rather than relying on interconnection planning screens. APQM includes re-structuring of distribution network and integration of renewable energy sources (RESs) to increase the supply reliability for critical loads, smart management, and optimised installation of power quality improvement devices (PQIDs) to enhance the distributed power quality improvement, adding ancillary functionalities to installed DER power electronic converters to increase the cost-effectiveness of DERs. Last but not the least, in this study, coordinated control of the PQIDs and high-penetration non-linear loads will also be discussed.

Active power quality improvement for unified renewable energy system with multilevel inverter and PEKF controllers

ABSTRACT Standalone microgrid with hybrid wind-PV-fuel cell renewable energy resources is necessary to meet the power demand in remote areas where the utility grid is not available. Renewable energy resources are erratic, (i.e.) sudden changes in the climatic condition generates variable output voltage that affects the reliability of the power electronics system providing voltage stress, switching losses and deliver harmonic deviation. Hybrid PV-wind-fuel cell provides multiple conversion stages, which reduces the efficiency of the system. In order to overcome this issue, this paper proposes new dc-dc boost converter for improving voltage gain and a predictive exogenous Kalman filter with fuzzy controller (PEKF) employed with bumble bee selective harmonic elimination-pulse width modulation for reducing the harmonic and maintains the system at steady state and also a cascaded 9-level H-bridge converter is utilized that operates at high voltage with stress per switching at lower voltage, higher efficiency and low electromagnetic interferences. The PEKF controller is utilized to predict the state and to improve power sharing injected by renewable energy resources. To show the effectiveness of the proposed scheme, simulations are done in working platform MATLAB/SIMULINK environment.

Supply Voltage and Grid Current Harmonics Compensation Using Multi-Port Interfacing Converter Integrated Into Two-AC-Bus Grid

A modified multi-port converter topology is proposed for active power quality control of two-ac-bus grid while maintaining a flexible integration of distributed dc energy sources. In this system, the lower converter cells work in voltage controlled mode to supply power to autonomous local critical loads with reduced harmonic distortions. At the same time, the upper converter cells working in current controlled mode are placed in between the main grid and the lower cells, to block the harmonic current from the local nonlinear loads to pollute the higher voltage grid current. In this proposed system, the upper and lower power cells harmonic control are well decoupled with minimal interferences. This features reduced computational load as there is no need to use any harmonic components extractions in the whole compensation process. In addition, the proposed harmonic compensation method has no interference with the interphase power flow control through zero sequence voltage injection. It has been examined that the proposed power quality control method works well in various conditions including that with large grid impedance and dc rail voltage variations.

Feasibility Analysis of Different Energy Storage Systems for Solar Road Lighting Systems

This paper investigates and analyses the feasibility of different energy storage systems for solar road lighting systems. The energy storage systems used in this paper are divided into two cases, namely, homogenous energy storage system [lead-acid (LA) batteries, lithium-ion (LI) batteries, and ultracapacitors (UCs)] and hybrid energy storage systems [lead-acid batteries with ultracapacitors (LA and UC) and lithium-ion batteries with ultracapacitors (LI and UC)]. Various solar power schemes are implemented based on stable and unstable solar irradiance conditions using an experimental setup. The economic analysis of the solar road lighting systems is performed based on the presented energy storage systems using discounted payback period (DPP), net present value (NPV), and internal rate of return (IRR). The installation of energy storage systems with individual and central systems for the solar road lighting system is also discussed. The results show that the LA batteries, LI batteries, and UCs yielded satisfactory active power quality for effective charging in all ranges of solar irradiance. However, the lifetimes of battery devices are degraded during dynamic active power charging. To overcome this shortcoming, hybrid energy storage systems are proposed using batteries and UCs. The use of LA batteries yields the lowest installation cost. However, the LI batteries offer the best economic viability in the long term. The cost of the UCs is too high to be used as an energy storage system for solar road lighting systems. However, the use of appropriate proportions of the UCs with batteries to reduce current and active power fluctuations for charging the batteries is economically viable.

Dual‐function PV‐ECS integrated to 3P4W distribution grid using 3M‐PLL control for active power transfer and power quality improvement

This study proposes a single-stage solar photovoltaic energy conversion system (PV-ECS) integrated to a three-phase four-wire (3P4W) distribution grid with dual-function capabilities, i.e. active power transfer and power quality (PQ) enhancement at the point of interaction (PoI). The PV-ECS system comprises of a solar photovoltaic array and a voltage source inverter (VSI), supplying active power (during daytime) to the distribution grid and connected single-phase and three-phase loads. Apart from transfer of power, the system also improves the PQ at the PoI by compensating reactive power and neutral current, attenuating harmonics, correcting power factor and balancing grid currents. During night, the VSI acts as a shunt active power filter mitigating PQ issues, thereby increasing the device utilisation factor. A three-phase magnitude-phase locked loop (3M-PLL) method is utilised to extract and estimate fundamental term of load currents and an incremental conductance algorithm is applied for maximum power point tracking. To demonstrate its effectiveness, the system is modelled and its performance is simulated on MATLAB and experiments are performed on a developed prototype in the laboratory.