Power Factor Compensation Research Articles

저압 유도전동기 부하 변동에 따른 역률 보상에 관한 연구

저압 유도전동기 부하 변동에 따른 역률 보상에 관한 연구

POWER FACTOR IMPROVEMENT BY USING STATIC VARIABLE COMPENSATOR

This project aims to improve the power factor of transmission lines using a static variable compensator. Traditional methods using large rotating parts were inefficient and prone to damage. Static VAR Compensation under FACTS employs Thyristor Switched Capacitors (TSC) controlled by a programmed microcontroller. This system compensates the power factor using thyristor-switched capacitors, where the zero voltage and zero current pulses are fed to a microcontroller. Previously, power factor compensation relied on large machines like synchronous condensers or switched capacitor banks. Shunt capacitive compensation, where a shunt capacitor is connected to draw current leading the source voltage, improves the power factor for inductive loads. The program controls opto-isolators interfaced with SCRs to achieve near-unity power factor. The project can be further enhanced with thyristor-controlled triggering for precise power factor correction.

Voltage-Controlled and Current-Controlled Low Voltage STATCOM: A Comparison

Inverter-based converters interconnecting DC microgrids and AC-microgrids/grids are in a strong expansion. Besides power exchange, the inverter can be requested to furnish ancillary services and, among them, power factor compensation. This work presents a comparison between voltage control and current control in a low voltage inverter in a STATCOM operation. Both strategies use P&O controllers to control power factor, but in voltage-control the P&O adjust modulation index while in current-control P&O adjusts the current reference. HIL simulations show that both controllers can efficiently increase power factor; however, voltage control requires additional overcurrent protection. Current control can easily limit the devices current, but requires an extra current measurement when compared to the voltage controller, therefore has increased cost.

Turning toward a smart region by implementing a hybrid power system

Distributed generation (DG) especially energy acquired from renewable energy sources (RES) plays a significant role in modern power sector due to high carbon emissions around the globe. Its emerging potential is feasible by implementing microgrids as they are beneficial for networks in terms of increasing flexibility and stability, providing frequency and voltage support, power factor compensation etc. This makes the investment into microgrid incorporating RESs attractive, while at the same time reducing overall investment in the grid. Higher cost and stochastic nature of intermittent RES are complications for the implementation and operation of such solutions. This paper will analyse economic feasibility of hybrid power system (HPS) implementation consisting of a wind generator (WG), a photovoltaic system (PVS), gas combined heat and power plant (CHP) and storage batteries. Each of the elements is optimized according to power demand and RES’s potential. Technical analysis of the grid integration, parallel operation of the system and the grid is analysed with an example of a real medium-voltage distribution network operating in Bosnia and Herzegovina by using quasi-dynamic load flow simulation of one-week time-period. Finally, different operating mechanisms and strategies will be proposed, following the minimal power form the grid premise to satisfy maximum usability of RES’s potential. It is shown that implementing such HPS would be beneficial in terms of both economy and, ecology, as well as in reducing energy losses. Besides, it will reduce power supplying costs and energy losses, as well as and secure better exploitation and utilization of natural renewable energy sources. These technologies positively affect power network by decreasing the risk of network-components overloading, better exploiting the power-generation facilities based on renewable resources and positively impacting voltage profiles. Similar places, situated on remote locations, may use this analysis as an example to follow, to reduce their costs of electricity, acquire more reliable and sustainable power supply, and embrace green future.

Double-Side Feeding and Reactive Power Compensation Using the Railway Interline Power Flow Controller

This paper gives an overview of the operating characteristics of the railway interline power flow controller (RIPFC) regarding the capability of transferring active power between two sections of an electrified railway line separated by a neutral zone and proposes its use for compensating the power factor at the substation instead of regulating the voltage level at the neutral zone. The basic analysis is based on simplified steady-state models for the energy supply architecture, while detailed time-domain simulations are used for more realistic tests. The paper mainly focus on active power balancing between two neighbouring substations and the global losses in the system. Other functionalities of the RIPFC system are also analysed, like reactive power compensation at the substations. The paper presents the main operating principles of the system, shows results for some representative scenarios (generic and reduced) and discusses the results. The most relevant conclusions are related to substation active power balancing and peak shaving, power factor compensation in the substation, voltage stability at the neutral zone and system power losses.

Net Zero Energy cost Building system design based on Artificial Intelligence

This paper presents a solution to the energy planning problem in buildings by implementing the net Zero Energy cost Building (nZEcB), a new concept that refers to buildings with zero or almost zero annual energy costs, using Artificial Intelligence (AI) techniques such as bidirectional long short-term memory, ordinary least squares linear regression, K-means, Pearson’s correlation, decision tree, and binary gravitational search algorithm. AI techniques are used to design the optimal structure of a distributed generation system. The system includes wind and photovoltaic renewable energy sources, a battery bank, and an automated capacitor bank for power factor compensation. A case study was conducted in a real public building with an annual consumption of 1.748 GWh, which resulted in the specification of a distributed generation system with a generation of 2.805 GWh per year. This system meets approximately 160.5% of the building’s electrical demand and 99.999% of annual energy costs, i.e., attending the nZEcB concept. The excess production of approximately 60% of the energy is necessary because the exported energy (feed-in tariff) has a lower value than that imported from the network, having to deduct costs with demand, in addition to having to compensate for losses in the battery banks. The project has a payback period of 6.79 years. This novel study demonstrates the feasibility and effectiveness of using AI techniques to achieve nZEcBs more efficiently, economically and sustainably.

Model predictive control for solid state transformer

The solid-state transformer (SST) is being presented as a technology that enables the construction of new power systems due to its many advantages. These benefits include reduced weight and volume compared to traditional transformers, power factor compensation, accurate output voltage regulation, harmonic mitigation, short-circuit current limitation, and voltage dip immunity, under certain conditions. Unlike other studies that only demonstrated the effectiveness of Model Predictive Control (MPC) in individual parts of the SST, this study shows the control of an entire SST using the MPC strategy. The performance of the SST during power system transients is evaluated to showcase the features of the SST by predictive control.

출력변동에 대응한 유도발전기의 역률 보상 제어

Induction generators are widely used in micro hydroelectric power plants. When the flow rate and the head change in the power plants, it becomes a parameter that changes the output of the induction generator. Induction generator has a low power factor even when operated at rated output with an inductive load. Also, if the induction generator is operated lower than the rated value or its output power is fluctuated, the change in the power factor becomes larger at a lower power factor. Therefore, a power factor compensation device such as a single capacitor or STATCOM is applied for power factor compensation. When the generator output is fluctuated, the converter voltage of STATCOM has the characteristic of fluctuating in conjunction with it. In this study, we propose the constant voltage source control method in STATCOM for power factor correction of induction generator and its feasibility is verified by the simulation in which the performance of power factor compensation by the capacitor, STATCOM without constant voltage control and STATCOM with constant voltage control are simulated and quantitatively compared. As a results, we confirmed that the STATCOM with constant voltage control can improve the power factor of induction generators a little comparing to the single capacitor or STATCOM without constant voltage control even if the generator output is fluctuated.

Automatic Power Factor Compensation

Paper present the project designed to correcting power factor for domestic, Commercial, Industrial. Which with hope to make the cost and energy usage efficient, because the energy source is depleting due to increase in population. Power factor is the ratio of real power and apparent power. This definition is mathematically represented as kW/kVA where kW is active power and kVA is apparent power (active + reactive). Reactive power is the non-working power generated by the magnetic and inductive load to generate magnetic flux. The increase in reactive power increase the apparent power so the power factor will decrease. Low pF will cause the industry to meet high demand thus making it less efficient. The main aim of this project is to increasing the current power factor of industries from 0.85 to 0.90. Power factor compensation contribute to reduction in current-dependent losses and increase energy efficiency while expanding the reliability of planning for future energy network. As technology develops, the gradual cost and efficiency penalty should reduce. Therefore, automatic power factor compensation device should become cost-effective and smaller device over time. That is the reason this project is using programmable device as it is a miniature architecture device.

유도발전기의 출력 변동시 역률 보상 커패시터의 자기여자에 관한 연구

Induction generators are widely used in mini- or micro-scale hydroelectric power plants. In the case of hydroelectric power generation in which changes in flow rate and head are large, the operation of the induction generator is often lower than the rated output. An induction generator is an inductive load and has a lagging power factor, and when operated at rated output, the power factor is around 0.8. The utility recommends that the customer compensate for the low power factor. The power factor compensation is planned so that the power factor of the induction generator will be about 0.95 under the condition of operating at the rated capacity. When the output of the induction generator decreases, the reactive power required for magnetization has a low change, but the active power decreases and the power factor is further lowered. At this time, a self-excitation phenomenon in which the reactive power for power factor compensation becomes higher than the reactive power required for magnetization may occur. When the self-excitation phenomenon occurs, electrical stress is provided to the induction generator, so in order to reduce the occurrence probability, the extent to which the generator

Performance Analysis and Energy Conservation of PV Based Hybrid Power System

The increase in energy consumption due to population expansion and scarcity of fossil fuels is happening simultaneously in developing countries like India. In this regard, commercial buildings are increasingly required to employ renewable energy sources (like PV) and conserve the energy for improving energy efficiency. This research article examines the performance of such PV-based hybrid power system, consists of 11 kV grid supply, 100 kWp PV plant & 200 kVA diesel generator. The results indicate that the addition of 68.34 kVAr shunt capacitor bank to Automatic Power Factor Compensation (APFC) panel, keeps the Power Factor (PF) unity and also eliminates the PF penalties in electricity bills. The maximum demand (MD) saving Rs 54528.00 (INR) on annual basis is achieved after the integration of PV with low voltage (433 V) distribution system and grid supply (11 kV). This integration has also reduced the average transformer loading to 64.73% and improved the transformer life. However the development of high current harmonics (average value 47.10%) must be reduced to ensure the life of the electrical load.

Powers and Power Factor in Non-Sinusoidal and Non-Symmetrical Regimes in Three-Phase Systems

The paper presents several theories related to definitions of powers and power factors in non-sinusoidal and non-symmetrical regimes. The theories must meet some requirements: (a) to facilitate the measuring of power quantities by using acquired electrical waveforms; (b) to support the correct quantification of powers and power factors for a fair charge; (c) to support solutions for efficient compensation of non-sinusoidal and non-symmetrical regimes, simultaneous with the power factor compensation along the fundamental harmonic. Only theories meeting the above-mentioned requirements are approached. Aspects specific to power definitions are discussed and commented. Three theories rely on the Fourier decomposition of non-sinusoidal waveforms, valid only for steady signals, whilst the fourth relies on the Discrete Wavelet Transform (DWT) and can also be applied to unsteady signals. Dedicated original data acquisition systems were used to acquire experimental data for three case studies. Data were analysed with original software tools, based on the Fast Fourier Transform and Discrete Wavelet Transform, implementing the approached theories. Comparisons between results yielded for analogue quantities proved that the approached theories satisfy the requirements for which they were created, except for the fourth theory, which can be used only for compensation purposes.

Automatic power factor correction based on Pearson similarity for distribution networks

In this paper, an online algorithm of automatic power factor correction (APFC) for distribution power grids is presented. The algorithm depends on Pearson similarity of voltage and current signals, which can easily be measured locally using voltage and current transformers, respectively. The proposed method not only evaluates the original power factor (PF), but also functions the APFC more quickly. In this work, the compensation index and reactive power compensation can be identified using new mathematical formulas based on the cross-correlation coefficients calculated between the phase voltage and current signals. Moreover, the coefficients are useful for detecting any abnormal condition. The method performance is examined on a large-scale network with real parameters’ data, which is simulated using the alternative transient program (ATP) environment, and the proposed algorithm is developed in MATLAB package. Numerous simulation results confirm the APFC relay feasibility, and the unity PF can be achieved. Besides, the proposed algorithm is characterized by its high operating speed, safety and accuracy for PF compensation, where its performance accuracy is greater than 99.7%. The approach offers novel operating/tripping curves based on the correlation coefficients for both power factor correction (PFC) and protection functions. Therefore, it is described with high level of functionality integration, and its security and sensitivity are controllable easily using the correlation settings.

Mitigation of Reactive Power and Harmonics in a Case of Industrial Customer

In most industrial plants, power quality is a major issue which hinders productivity and efficiency of the plants due to the use of semiconductor based loads and non-linear loads. As a result, to address the power quality problems in these industries, specialized power devices such as the Unified Power Quality Conditioner (UPQC), can be installed at the customer's location to resolve practically all power quality issues. UPQC consist of a series of active power filters (APF) which mitigate voltage quality issues and shunt active power filters which are used to reduce current quality issues, like harmonics and reactive power burdens. This paper, therefore presents an investigation and assessment of the power quality problems associated with Bahir Dar Textile Share Company. This was achieved by examining the voltage and current harmonic levels of various types of loads using PI and fuzzy logic controllers by measuring the level of total harmonic distortion (THD) with and without the insertion of the UPQC. The novelty of this paper is the implementation of the controller based customized UPQC for power factor and reactive power compensation. It was observed that by designing the system without and with UPQC, the results of the FFT analysis show that the fuzzy logic controller (FLC) reduced the harmonics level of the load voltage and current by 1.10% and 2.14% respectively. Generally, harmonics was alleviated by 90%, reactive power was reduced by 20%, and power factor was improved by 33%. Hence, the proposed UPQC is capable of holding the voltage and current harmonics levels within the acceptable limit, which satisfies the standards imposed by IEEE 519-1995.

The electric substations compensating devices’ distribution optimization

The article discusses methods for calculating electrical networks when choosing the consumer compensating devices’ location. The main network and calculation module of a complex network is analyzed. The mathematical support of the reactive power factor compensation (PFC) problem is described in regional power systems, the areas of application of individual models are substantiated, and the results of the practical use of the corresponding calculation results are analyzed.

Affine projection sign algorithm based control for mitigation of distribution side power quality problems

AbstractThis paper proposes the implementation of Affine Projection Sign Algorithm (APSA) based control for DSTATCOM to mitigate distribution side power quality issues like harmonic elimination, reactive power compensation, load balancing, power factor compensation, voltage regulation, etc. Affine projection algorithms have already finds application in power quality mitigation, but they suffer from high complexity and degraded performance due to impulsive interference. Whereas, sign algorithms are known to be robust against the impulsive noise and converges faster. Hence, sign algorithm with affine projection is proposed for mitigation of power quality problems in this work. APSA is used to estimate the reference active and reactive power component of polluted load current, which is further used to generate the reference signal for DSTATCOM. The performance of the algorithm is investigated for some real operating conditions of power system network in MATLAB/SIMULINK environment. The algorithm is tested in real‐time simulator for validation. The result shows that the control algorithm is able to resolve distribution side power quality problems with fast convergence.

Analisa Kualitas Daya Listrik Pada Gardu Distribusi Universitas Khairun

The large number of applications of nonlinear loads in the electric power system has made the system current very distorted with a very high percentage of current harmonic content, THD (total harmonic distortion) can damage the power factor compensation capacitor, making the system power factor worse, causing interference. to the telecommunication system, increase system losses, cause various kinds of damage to sensitive electrical equipment, all of which cause the use of electrical energy to be ineffective which results in poor power quality. In this study, the collection of data obtained was based on methods such as the following, namely the measurement method. This measurement method measures the harmonic voltages and currents caused by non-linear loads.

Optimal Allocation of Comprehensive Resources for Large-Scale Access of Electric Kiln to the Distribution Network

With the significant progress of the “coal to electricity” project, the electric kiln equipment began to be connected to the distribution network on a large scale, which caused power quality problems such as low voltage, high harmonic distortion rate, and high reactive power loss. This paper proposes a two-stage power grid comprehensive resource optimization configuration model. A multi-objective optimization solution based on the joint simulation platform of Matlab and OpenDSS is developed. The solution aims to control harmonics and optimize reactive power. In the first stage, a multi-objective optimization model is established to minimize the active network loss, voltage deviation, and equipment cost under the constraint conditions of voltage margin, power factor, and reactive power compensation capacity. Furthermore, the first stage uses a particle swarm optimization (PSO) algorithm to optimize the location and capacity of both series and parallel compensation devices in the distribution network. In the second stage, the optimal configuration model of the active power filter assumes the cost of the APF as the objective function and takes the harmonic voltage content rate, the total voltage distortion rate, and the allowable harmonic current as the constraint conditions. The proposed solution eliminates the harmonics by uniformly configuring active filters in the distribution network and centrally control harmonics at the system level. Finally, taking the IEEE33 distribution network as the object and considering the change of electric furnace permeability in the range of 20%–50%, the simulation results show that the proposed algorithm effectively reduces the distribution network’s loss, its harmonic content and significantly improve its voltage.

Control of Single-Phase Electrolytic Capacitor-Less Isolated Converter for DC Low Voltage Residential Networks

In recent years, there has been a desire to improve electricity generation and consumption, to reach sustainability. Technological solutions today allow a rational use of electricity with good overall performance. Traditionally, from production to distribution, electrical energy is AC-supported for compatibility reasons and easy voltage level transformation. However, nowadays most electric loads need DC power to work properly. A single high-efficiency central AC-DC power converter may be advantageous in eliminating several less efficient AC-DC embedded converters, distributed all over a residential area. This paper presents a new single-phase AC-DC converter using one active bridge (most isolated topologies are based on the dual active bridge concept) and a high-frequency isolation transformer with low-value non-electrolytic capacitors, together with its control system design. The converter can be introduced into future low-voltage DC microgrids for residential buildings, as an alternative to several embedded AC-DC converters. Non-linear control techniques (sliding mode control and the Lyapunov direct method) are employed to guarantee stability in the output DC low voltage with near unity power factor compensation in the AC grid. The designed converter and controllers were simulated using Matlab/Simulink and tested in a lab experimental prototype using digital signal processing (DSP) to evaluate system performance.

Optimization of power flow through facts in electrical networks

A mathematical model is presented for optimizing power flows in an electric network with a flexible controlled alternating current power transmission device - FACTS. The range of questions on the problem of optimizing the power flow in electric networks with one of the FACTS devices, the SVC static power factor compensator, has been expanded and investigated. The Lagrange function for the SVC device is proposed, which serves as the basis for obtaining a linearized equation and determining the optimum of the objective function.The method and algorithm of the optimization problem in the electric power system containing devices of the FACTS technology have been synthesized. The mathematical model allows for flexible and reliable optimization of the electrical power system. Flexibility is explained by the universality of the model, and reliability is explained by the high convergence rate of the Newton method used.