Electric power utilities and end users are becoming increasingly concerned about the quality of power supply. To reduce the losses caused by power service disturbances, mitigation devices are available for improving the power quality. The first step in the power quality improvement is to monitor the system behavior by using some Electronic recording devices. A design and implementation of a digital signal processor based power quality monitoring device is presented in this thesis. Several event-triggering methods are studied and implemented to detect system disturbances. Simulation and test results indicate that the proposed design can meet the requirements for power measurements and transient event recording during steady and transient states.

Power quality has a great effect on the operation of system loads. To analyze its effects and the possible economic losses due to system disturbances, there is an immediate need of a power quality monitoring system. With an effective communication system, network disturbance data can be gathered and analyzed efficiently such that outage duration and its consequent losses can be reduced. This thesis presents communication network performance simulation results of different types of communication schemes used in a power quality monitoring system. Discrete event simulation method is used to study the end-to-end delay times of different communication architectures. Based on these simulation results, system designers can choose the best option to meet their data communication requirements in power quality monitoring.

Thesis deals with the design of intelligent electrical socket. At the beginning of the thesis, there are described the characteristics of the distribution network in the Czech Republic and the ways of measuring these properties. The selected integrated circuit that realizes the measurement is described in detail. The third chapter deals with the current possibilities of power management, especially from the perspective of the distribution company and the concept of smart networks. The fourth chapter deals with the selection of communication interface suitable for smart socket as an element of smart home. The selected IEEE 802.15.4 standard and the microcontroller implementing the communication itself are described in more detail. The following part of the work is about design of the intelligent socket development board, on which the concept is tested and the design of the final hardware is described in this chapter. The last chapter describes the measurement results realized by the created device.

Developments in measurement technology, communication and data storage have resulted in measurement systems that produce large amount of data. Together with the long existing need for characterizing the performance of the power system this has resulted in demand for automatic and efficient information-extraction methods. The objective of the research work presented in this thesis was therefore to develop new robust methods that extract additional information from voltage and current measurements in power systems. This work has contributed to two specific areas of interest.The first part of the work has been the development of a measurement method that gives information how voltage flicker propagates (with respect to a monitoring point) and how to trace a flicker source. As part of this work the quantity of flicker power has been defined and integrated in a perceptionally relevant measurement method. The method has been validated by theoretical analysis, by simulations, and by two field tests (at low-voltage and at 130-kV level) with results that matched the theory. The conclusion of this part of the work is that flicker power can be used for efficient tracing of a flicker source and to determine how flicker propagates.The second part of the work has been the development of a voltage disturbance classification system based on the statistical learning theory-based Support Vector Machine method. The classification system shows always high classification accuracy when training data and test data originate from the same source. High classification accuracy is also obtained when training data originate from one power network and test data from another. The classification system shows, however, lower performance when training data is synthetic and test data originate from real power networks. It was concluded that it is possible to develop a classification system based on the Support Vector Machine method with “global settings” that can be used at any location without the need to retrain. The conclusion is that the proposed classification system works well and shows sufficiently high classification accuracy when trained on data that originate from real disturbances. However, more research activities are needed in order to generate synthetic data that have statistical characteristics close enough to real disturbances to replace actual recordings as training data.

Krav på överföringen av el ställs i föreskrifter och standarder för att hålla störande elkvalitetsparametrar inom godtagbara nivåer i nätet. På senare år har användandet av elnätet förändrats med nya belastningar, distribuerad generering och en ökande mängd kraftelektronik. Detta bidrar till ett ökat behov att utföra kontinuerlig övervakning av parametrar som kan orsaka problem för kund och nätägare. I samband med installationen av de nya ”smarta elmätarna” hos kunder finns möjligheten att få utökad elkvalitetsövervakning i stora delar av nätet. Till följd av detta har Geab valt att se över sin elkvalitetsövervakning. I denna rapport ligger fokus på vilka parametrar som ska övervakas, var i nätet de ska övervakas och hur man kan bedriva detta effektivt med en bra täckning av nätet. Syftet med denna övervakning är primärt att verifiera att nätet uppfyller standard. Men andra fördelar finns, bland annat kan åtgärder vidtas i ett område innan gränsvärden överskrids. Det går även att använda utrustningen för störningsanalys. I denna rapport sammanställs vilka parametrar som ska övervakas och vilka krav som gäller för mätutrustning vid mätning av elkvalitet enligt standard och föreskrift. Förslag ges även på var och hur mätning kan utföras. Sju mätsystem har jämförts utifrån dessa parametrar. Baserat på resultatet rekommenderas att fasta mätare installeras i fördelningsstationer på nedsidan av mellanspänningstransformatorn, i kombination med smarta elmätare i nätstation och i anslutningspunkt mot kund i lågspänningsnät. Detta för att få en kostnadseffektiv täckning och hantering av elkvalitetsövervakning i nätet. På grund av det stora antalet mätinstrument bör övervakning av elkvaliteten ske med hjälp av gränsvärdesövervakning och automatiskt genererade rapporter. Detta minskar hanteringstid för personal då portabla mätare inte behöver monteras men även då systemet behandlar den insamlade informationen på egen hand. Eftersom gränsvärdesövervakning kan missa vissa avvikelser bör även stickprov utföras för att verifiera den automatiska övervakningen. / Requirements for the transmission of electricity are set in regulations and standards to keep disruptive power quality parameters in the grid within acceptable levels. In recent years, the use of the electrical grid has changed with new loads, distributed generation, and an increasing amount of power electronics. This contributes to an increased need to perform continuous monitoring of parameters that can cause problems for customers and network owners. With the installation of the new ”smart meters” at customers connection point, there is the possibility of having extended power quality monitoring in large parts of the network. As a result, Geab has chosen to review its power quality monitoring. This report focuses on which parameters are to be monitored, where to monitor and how this can be done effectively with good coverage of the network. The purpose of this monitoring is primarily to verify that the network meets the requirements. But there are other advantages, for example, steps can be taken before a limit value is exceeded in an area. It is also possible to use the equipment for analyzing disturbances. This report summarizes which parameters to monitor and which requirements apply to measuring equipment when measuring power quality in accordance with standards and regulations. Suggestions are also given on where and how measurement can be performed. Seven measurement systems have been compared based on these parameters. Based on the results, the recommendation is that fixed meters be installed in substations on the medium voltage side of the transformer, in combination with "smart meters" in distribution substations and at the connection point to the customer in the low voltage network. This will result in cost-effective coverage and management of power quality monitoring in the network. Due to a large number of measuring instruments, monitoring of power quality should take place with the help of automatic limit monitoring and automatically generated reports. This approach will give alarms/warnings if any parameter exceeds its limit. This reduces handling time for personnel as portable meters do not need to be installed but also when the system processes the collected information on its own. Since automatic detection of exceeded limit values may miss certain deviations, random sampling should be performed to verify the automatic monitoring.

The problem with the implementation of the PV generators is that majority of the UNDP offices are in developing and underdeveloped countries. Majority of these countries experience various problems with the power quality from the national electrical grid. There is also a second problem with the installed PV system, the problem is that the installed PV sources show a significant decrease in the expected annual yield ranging from 10 % – 60 % in some cases. The main aim of this thesis is to analyze the power quality in three countries (Nepal, Sao Tome and Namibia) and find the correlation between power quality and PV generation. This aim is done in five steps. The first step is the collection of measured data from the grid for a specific period of one year from July 2020 to August 2021. The collected data includes the current, voltage, power factor, frequency, reactive and active power. To achieve this, the Acuvim II power quality analyzer was sent to these three countries. In the second step, a literature review is done to research about power quality problems, identifying the power quality problems and analyzing the problems created by these identified power quality problems. In the three countries, undervoltage, overvoltage, swells, and sags where the main power quality problems which were recorded. The third step is a system case study process in which an in-depth analysis is done on the three PV systems and a simulation is done to understand the solar parameters which includes the specific yield, and performance ratio. The fourth step involves comparing the collected data from the PQ analyzer with the simulation results and determine the effects the power quality problems and system design have on the low annual yield. Also, the yearly amount of overvoltage and undervoltage in the three countries within the analysis period was analyzed. The voltage and fluctuation analysis also includes other power quality parameters which were measured. The collected parameters were analyzed and the correlation between the electrical grid requirements in the three countries were made with the recorded data. The final step involves recommending improvements and optimization techniques for the three systems to improve life cycle cost and long-term vision. Thus, analyzed results and simulated results are compared to evaluate the performance. The PV system in Namibia had the best grid conditions with all the grid parameters operating within the defined grid limits, there was a 30 % reduction in annual energy production in the Nepal system due to poor power quality conditions which included overvoltage, undervoltage, and frequency deviations. There was also a 50 % energy loss in the annual production of the PV systeminstalled in Sao Tome. Sao Tome also had the highest number of recorded outages with an average of 6 – 7 hours of outages recorded daily. Power quality problems recorded in Sao Tome included voltage fluctuation problems and frequency deviations.

Demand for electrical power is increasing everyday. Along with the increase in power demand, the characteristics of the loads are also changing. From being high power consuming, simple, robust loads, today loads are more efficient, but at the same time more sensitive. The performance and life of these highly sensitive loads depend a lot on the quality of power supplied to them. <p>Power quality is any deviation of the voltage or current waveform from its normal sinusoidal waveshape. These disturbances include, but are not limited to, sag, undervoltage, interruption, swell, overvoltage, transients, harmonics, voltage flicker and any other distortions to the sinusoidal waveform. Occurrence of one or more of such disturbances is called a power quality event. Automatic classification of these disturbances is important for quick determination of the causes and to characterize possible impacts of the disturbances.<p>Modern microprocessor based protective relays have numerous integrated functions that allow them to provide information on power quality events. It is proposed to utilize the existing numerical relays to analyze the quality of power at any point in the power system. The numerical relays can be programmed to capture the oscillographic waveform or any disturbance on the analogue signal or change of state of the digital signals and store it in the form of Common Format For Transient Data Exchange (COMTRADE) format. These records are then transferred to a central monitoring workstation for off-line analysis. <p>This thesis describes a technique to automate the classification and analysis of the power quality events using relay recorded data. The technique uses voltage duration and magnitude (as specified in the IEEE Std. 1159 - 1995, IEEE Recommended Practice for Monitoring Electric Power Quality) of three phases to detect and classify the events. The classified results are then presented in a user-friendly graphical form. Fast Fourier Transform (FFT) is used to estimate the fundamental frequency and harmonic components in power systems. The graphical user interface of the power quality analysis tool is developed using Microsoft Visual C++ IDE and the algorithms are programmed in C++. <p>The proposed technique was tested using data obtained by simulating different power system disturbances as well as on the data recorded by relays. The algorithms were able to classify the power quality events accurately. In the future, this facility will: enhance the real time monitoring of power quality and provide statistical analysis of available power quality data. From the utility viewpoint, it would allow them to monitor power quality in a cost effective manner and assist in preventive and predictive maintenance besides helping them to fix differential tariff based on the quality of the delivered power. It may also turn out to be a smart tool for them to penalize the consumer polluting the power quality.

Demand for electrical power is increasing everyday. Along with the increase in power demand, the characteristics of the loads are also changing. From being high power consuming, simple, robust loads, today loads are more efficient, but at the same time more sensitive. The performance and life of these highly sensitive loads depend a lot on the quality of power supplied to them. <p>Power quality is any deviation of the voltage or current waveform from its normal sinusoidal waveshape. These disturbances include, but are not limited to, sag, undervoltage, interruption, swell, overvoltage, transients, harmonics, voltage flicker and any other distortions to the sinusoidal waveform. Occurrence of one or more of such disturbances is called a power quality event. Automatic classification of these disturbances is important for quick determination of the causes and to characterize possible impacts of the disturbances.<p>Modern microprocessor based protective relays have numerous integrated functions that allow them to provide information on power quality events. It is proposed to utilize the existing numerical relays to analyze the quality of power at any point in the power system. The numerical relays can be programmed to capture the oscillographic waveform or any disturbance on the analogue signal or change of state of the digital signals and store it in the form of Common Format For Transient Data Exchange (COMTRADE) format. These records are then transferred to a central monitoring workstation for off-line analysis. <p>This thesis describes a technique to automate the classification and analysis of the power quality events using relay recorded data. The technique uses voltage duration and magnitude (as specified in the IEEE Std. 1159 - 1995, IEEE Recommended Practice for Monitoring Electric Power Quality) of three phases to detect and classify the events. The classified results are then presented in a user-friendly graphical form. Fast Fourier Transform (FFT) is used to estimate the fundamental frequency and harmonic components in power systems. The graphical user interface of the power quality analysis tool is developed using Microsoft Visual C++ IDE and the algorithms are programmed in C++. <p>The proposed technique was tested using data obtained by simulating different power system disturbances as well as on the data recorded by relays. The algorithms were able to classify the power quality events accurately. In the future, this facility will: enhance the real time monitoring of power quality and provide statistical analysis of available power quality data. From the utility viewpoint, it would allow them to monitor power quality in a cost effective manner and assist in preventive and predictive maintenance besides helping them to fix differential tariff based on the quality of the delivered power. It may also turn out to be a smart tool for them to penalize the consumer polluting the power quality.