Algorithm Research and Implementation of Power Quality Parameters Analysis

The rapid advancement of power system technologies has significantly transformed the way electrical power quality (PQ) is monitored, managed, and improved. The increasing penetration of non-linear loads, automation systems, and renewable energy sources has intensified power quality challenges, including harmonic distortion, voltage sags, voltage fluctuations, and transient disturbances. This study aims to analyze the impact of modern technological approaches on power quality enhancement in contemporary power systems. A descriptive-analytical research methodology was employed through a systematic review of recent scientific literature, international standards, and technical reports related to power quality management. The collected data were analyzed using qualitative content analysis and comparative evaluation to assess the effectiveness of automation, machine learning, Internet of Things (IoT)-based monitoring systems, and power electronic mitigation devices. The results indicate that integrated technological solutions significantly improve power quality performance compared to conventional approaches. Machine learning techniques, particularly Artificial Neural Networks, demonstrate high accuracy in disturbance classification and adaptive control, while IoT-based systems enable real-time monitoring and rapid response to power quality deviations. Furthermore, power electronic devices such as Active Power Filters, Static Var Compensators, and Dynamic Voltage Restorers effectively mitigate harmonics and stabilize voltage. However, challenges related to implementation cost, system complexity, cybersecurity, and regulatory inconsistency remain. The study concludes that an integrated, intelligent, and data-driven framework is essential for sustainable power quality management in modern power systems.

Providing high-quality, reliable, and continuous power to consumers is crucial in today's power systems. However, the increasing demand and widespread use of power electronic devices have introduced various power quality issues, including voltage sags, swells, and harmonics. To mitigate these issues, advanced power electronic devices have been employed. This project focuses on utilizing a Unified Power Quality Conditioner (UPQC) integrated with a solar PV array to maintain optimal power quality. The UPQC combines series and shunt compensators, enabling it to perform multiple tasks and improve power quality. The series converter addresses grid-side power quality problems, such as voltage sags and swells, while regulating the load voltage and PCC voltage. Meanwhile, the shunt compensator mitigates current harmonics caused by nonlinear loads, leveraging power from the PV array. A synchronous reference frame control strategy based on a moving average filter generates the reference signal. The UPQC model is developed and simulated using MATLAB/SIMULINK software to evaluate its performance. Keywords: Solar PV, UPQC, Power Quality.

14 - Harmonic distortion effect of large-scale hydropower storage based on doubly fed induction machine in power system

Abstract- Based on Fast Fourier Transform (FFT), power quality indices (PQIs) definitions contained in the standards cannot be successfully applied for non-stationary signals analysis in unbalanced three-phase systems with non-sinusoidal conditions. Unlike FFT, Discrete Wavelet Transform (DWT) gives more accurate definitions preserving time-frequency information and reduces the computational effort. This paper proposes a comparative analysis of definitions employing these two instruments for unbalanced three-phase systems case in sinusoidal and nonsinusoidal situations using waveforms captured with data acquisition system which contains Hall voltage and current transducers. The experimental testing of harmonic distortion was made for a RL unbalanced three-phase load, a three-phase rectifier with diodes (TPRD) and a rectifier with near sinusoidal currents (RNSIC). I. I NTRODUCTION For the electric power quality monitoring, the IEEE working group has analysed the customers expectations concerning electric power delivery, the susceptibility limits of the electric and electronic equipments connected at the electric network and thus obtained the standards regarding the evaluation methods of electric power quality, the parameters that define this concept and the functioning classes of the measurement tools [1-3]. In the last years electric power quality became un important issue in the power systems domain because of the increased usage of nonlinear loads which are producing great harmonic distortion in power supply [4-12, 33-36]. Voltage and current quality can be determined based on the deviations between the real voltage/current and the ideal voltage/current waveforms [13]. These deviations are counted power quality disturbances and can be classified as stationary (with time unchangeable characteristics) or non-stationary (with time changeable characteristics) and each of them as sinusoidal or non-sinusoidal. The Fast Fourier Transform (FFT) approach in Power Quality Indices (PQIs) definition is replaced in this study with a time-frequency domain approach using Discrete Wavelet Transform (DWT). This method eliminates the FFT drawbacks as high computational effort, time related information loss, spectral leakage and provides representations for any non-stationary waveforms [14-17]. DWT is a useful tool in the waveforms analysis due to its accuracy and sensitivity at signal irregularities [5], [32]. The waveforms of voltage and current are obtained using a data acquisition system with linear/nonlinear loads composed of a Digital Signal Processor (DSP) board with high-speed 12 bit Analog to Digital Converters (ADC) coupled to a three-phase system using the Hall transducers. This paper presents a comparative analysis of DWT based measurements of power quality indices and the IEEE Standard 1459-2000 based values using unbalanced linear three-phase systems and nonlinear power loads. The power quality disturbances are calculated with a RL unbalanced three-phase load, a three-phase rectifier with diodes (TPRD) and a rectifier with near sinusoidal currents (RNSIC). II. T

The extensive use of power electronics devices in power systems, including rectifiers and inverters, presents considerable issues regarding power quality. One problem is the creation of current and voltage harmonics, which result in load waveform distortion, voltage fluctuation, voltage drop, and equipment overheating. Harmonic current sources are prevalent in commercial, institutional, and medical establishments, encompassing computer power supplies, fluorescent lights with electronic ballasts, elevator motors, and electrical devices using switch-mode power supplies. Active power filters (APF) represent the most effective method for harmonic reduction and may be used across many applications. This study employs a digital active power filter to eliminate harmonics from the source current in a grid system characterized by non-linear demand. Nonlinear loads are essential components of every power system. The advent of power electronics has resulted in switching components constituting a substantial portion of electrical demand. These features create discontinuities in lines, exacerbating line losses and diminishing power quality and sine wave integrity. Passive filters effectively eliminate harmonics at specified frequencies within the design. Active filters, conversely, operate in accordance with the prevailing harmonics. This work develops a shunt active power filter that mitigates current harmonics generated by non-linear loads. The active filter includes a voltage source converter (VSC) that functions in conjunction with a DC coupling capacitor. The VCS delivers power at the point of common coupling (PCC). The reference current is obtained by the instantaneous power theory. The instantaneous power theory, or PQ theory, has been enhanced with the FIS control system to optimize DC voltage generation over the DC link capacitor. The fuzzy system substituting the PI controller has a 49-rule base structure organized in a 7x7 configuration for the generation of error signals. A comparative study of DC voltage and total harmonic distortions (THDs) is conducted using MATLAB software and the FFT analysis tool..

The constant failure in cyber security in power systems and substation automation that has crippled business activities that mostly depend on power to run their routine activities are caused by Lack of Adequate Security Measures, Human Error, Outdated Software and Hardware, Insufficient Training and Awareness, Insider Threats, Weak Access Control Mechanisms, Inadequate Network Segmentation, Failure to Patch Vulnerabilities, Complexity of the System, Third-Party Vendor Risks and Denial of Service (DoS) Vulnerabilities. This is surmounted by introducing improved cyber security in power systems and substation automation using intelligent based system. To achieve this, it is done in this procedure characterizing and establishing the causes of failure in cyber security in power systems and substation automation, designing a SIMULINK model for cyber security in power systems and substation automation, designing a rule base that will reduce the causes of failure in cyber security in power systems and substation automation,training ANN in the rule base for effective reduction of causes of failure in cyber security in power systems and substation automation, developing an algorithm for the process, designing a SIMULINK model for improving cyber security in power systems and substation automation using intelligent based system and validating and justifying the percentage of improvement in the reduction of causes of failure in cyber security in power systems and substation automation. The results obtained were the conventional Lack of Adequate Security Measures that cause failure in improving cyber security in power systems and substation automation was 25%. On the other hand, when an intelligent based system was incorporated into the system, it drastically reduce the cause failure in improving cyber security in power systems and substation automation to 21.53%, the conventional outdated software and hardware that cause failure in improving cyber security in power systems and substation automation was 15%. Meanwhile, when an intelligent based system was inculcated in the system, it became reduced to 12.92% thereby enhancing the performance of cyber security in power systems and substation automation by 2.08%, the conventional Weak Access Control Mechanisms that cause failure in improving cyber security in power systems and substation automation was 8%. However, when an intelligent based system was integrated in the system, it was reduced to 6.9% and the conventional Denial of Service (DoS) Vulnerabilities that cause failure in improving cyber security in power systems and substation automation was 2% while when an intelligent based system was incorporated in the system, it automatically reduced to 1.7%. Finally, with these results obtained, It vehemently shows that the percentage improvement in cyber security in power systems and substation automation was 0.3%.

Continuous research to achieve high luminous efficiency with low cost LED lamps has widen the field of LED lighting applications, which dictates the need to study different characteristics of commercial LEDs and their impact on power quality parameters. This paper addresses the negative influence of utilizing LED lamp as a lighting source on power grid and on public health. The operation of the LED and its behavior as a nonlinear load has been further discussed. Various experimental tests that include harmonic analysis, voltage flickering voltage sag, swell and voltage harmonics have been conducted to investigate current and voltage quality issues. This paper aims at a better understanding to the characterization of commercial LED lamps in order to highlight the need for power quality improvement techniques for such an application also the need for new developments that improve LEDs internal power electronic driving circuit.

In this modern generation almost every power supplies are non-linear loads which contains electronic devices that do not conduct current over the full cycle of the applied voltage, and thus they introduce harmonics into the power network. Electronic front end of non linear load makes them more efficient than linear loads and these non-linear front ends are one of the source of harmonic. Harmonic is nothing but a signal or a wave having frequency is an integral (whole-number) multiple of the frequency of some reference signal or wave or fundamental frequency. Harmonic causes losses in the power distribution network and can lead to increased cost due to maintenance, failures or device de-rating and thus decreases the power quality of the power distribution network. Power quality may be defined as a set of electrical characteristics that allows a piece of equipment to function in its desired manner without any interruption and significant loss of performance or life expectancy. Total harmonic distortion (THD) is an important figure of merit used to quantify the level of harmonics in voltage or current waveforms. In this paper Distribution Static Compensator (DSTATCOM) with Synchronous Reference Frame based control which taking into account Three-Level Cascaded multi level Inverter for minimization of harmonics in Power System. This Three level Cascaded multilevel inverter supply low harmonics distortion, reduced number of switches, suppression of switching losses and take out the Total Harmonics Distortion (THD).

Power quality has become a serious concern as the usage of nonlinear loads is increasing rapidly. Power quality has some substantial effects on power systems, one of them is transformer derating. In this paper, the harmonic impacts of DC-DC fast charging of EV along with residential, small-scale industrial, and commercial complex loads on the transformer derating in a radial distribution network (RDN) has been studied using three different test cases. Firstly, a DC-DC fast charging model has been simulated by optimal tuning of the PI controller, and the harmonic spectrum has been collected. Then harmonic power flow analysis is performed using the Backward/Forward sweep (BFS) load flow analysis method, for the calculation of fundamental and harmonic voltages and currents. Consequently, transformer derating is calculated for each case. It can be seen that this harmonic spectrum has a direct impact on it.

In current era the operation of power electronic devices in power system is becoming enormous to enhance the utilization of electric power in an interconnected distribution system to increase the reliability of sophisticated lifestyle of deregulated electricity market, which alarms the power system engineers about the impact of power quality issues and the need for improving the quality of electric power supplied to the consumers. The effects produced by the interconnected power system having renewable energy based electric power generating systems and non-linear loads cause harmonics, voltage variations in the system, which can be mitigated with the help of Unified Power Quality Conditioner (UPQC). This paper presents the performance comparison two different control techniques adopted in the design of UPQC namely synchronous detection method (SDM) and instantaneous direct and quadrature (id-iq) method. The proposed UPQC mitigates the voltage variations such as voltage sag/swell and harmonics present in an interconnected distribution system and improve the electric power quality supplied to the consumers as per the IEEE standard 519-1992. The application of SDM and id-iq method is to generate the compensation current, voltage required by the UPQC and results in the effective elimination of short time voltage variation disturbances and harmonics at the point of common coupling (PCC). The entire system has been modeled using MATLAB SIMULINK environment.

Energy Internet (EI) is the energy network based on the power system and information architecture. With the access of the renewable energy power generation equipment, energy storage device and various types of power load to power grid, the traditional power system equipment can't meet the diversity of power supply, energy multi-directional flow, active management of power flow and other requirements. How to use the advanced power electronics technology has become the core of the effective control to EI. The state of art of EI at home and abroad is introduced firstly, and the concepts and research progress of EI in different countries are compared in this paper. Then the application status of power electronic technology in EI is introduced. The working principle and function of three important power electronic devices are mainly introduced, which consists of solid state transformer (SST), energy router, and energy switch. Finally, the future development trend of power electronic technology is pointed out based on the analysis of the existing research results at home and abroad.

Power quality analysis is one of the most important subjects of every power systems' interconnected parts. In fact, the nonsinusoidal regime represents the real operation mode of all the power systems, due mainly to distribution and consumers. Several parameters of power quality analysis are used by every national power system operator to impose specific standard limits and regulation which ensure optimal conditions of the electrical energy quality. Generally, all the limit values must be respected, even though they indirectly depend on one another. This paper proposes new relations between some parameters of power quality for the case of most common linear and inductive consumers, in order to unify the limits imposed on nonsinusoidal regime. Starting by the definition of relative values of voltage and current harmonics a new nonlinear dependence between the power factor and the total harmonic distortion of voltage and current is established. A quantitative approach of the nonlinear function has been assessed by using Matlab tools. The results are compared and discussed to the measured data for a large industrial consumer in two cases: with and without filters for power factor correction.

In recent years, power electronics devices have evolved, and used for varies applications. Also, this device caused the problem of power quality in electrical system. In the utility side arc furnaces, variable frequency drives (VFD), personal computer, fluorescent lamp such non-linear load produces current harmonics. For consumer and distributed side the power quality is an important issue. The active power filter which is capable for improving the power quality and reactive power compensation. In this paper the harmonics problem which is created by non-linear load is discussed. Shunt active filter is used for eliminating the harmonics from non-linear load and in the retrieval technique for controlling the current hysteresis current controller is used. In this paper for producing the reference current instantaneous reactive power (PQ) theory is used. The simulation result of shunt active filter using PQ theory is carried out using Matlab-Simulink toolbox.

The power quality domain in power system networks has received more attention recently because of the increase in sensitive equipment, non-linear load disturbances, and the utilization of Renewable Energy Sources (RES). In case of distributed generation, which could occur from consumers to utilities, power quality quantifies the suitability of electric power supplied from the utilities to the commercial, industrial, and residential users. A minimum of half of the total disruptions to power quality are related to voltage quality. This research concentrated an amplitude-frequency estimation based methods, Power quality Disturbance Classification and Filtering techniques for harmonic mitigation. The enhancement of power quality in a three-phase nonlinear load power system is the subject of this research. Shunt Active Power Filter (SAPF) is used in real-time applications for fault detection and harmonic suppression. The suggested work uses a digital signal processor (DSP) (28335) and a shunt active power filter (SAPF) to achieve power quality disturbance detection and harmonic reduction on hardware system. In addition to applying shunt compensation devices for harmonic detection, the designed hardware model is tested for power quality disturbance categorization of voltage sag, harmonics, and interruption and Total Harmonic Distortion (THD) is 4.3% in this case. The overall implementation of the hardware using -Fuzzy algorithm is found to be satisfactory.

The integration of renewable energy sources, such as solar and wind power, into Electric Vehicle (EV) charging stations presents a promising solution for sustainable transportation. However, ensuring high power quality in these systems is essential for the efficient operation of both the charging stations and the grid. This project compares the power quality improvement in solar and wind-based EV charging stations interconnected with a three-phase grid. Power quality parameters such as voltage stability, harmonics, power factor, and frequency regulation are evaluated for both systems. Solar-based systems, benefiting from predictable energy generation during daylight, generally exhibit superior performance in terms of voltage stability, harmonic reduction, and power factor correction, with the ability to integrate seamlessly with energy storage solutions. In contrast, wind-based systems offer the advantage of continuous power generation in regions with consistent wind, but they face challenges due to variability in wind conditions and more complex control mechanisms. Both systems contribute to frequency regulation and voltage support, albeit with different levels of consistency. The project concludes that while both solar and wind- based EV charging stations can significantly improve power quality, the optimal solution depends on local environmental factors, grid infrastructure, and the need for energy storage integration