Developing A Medium-Voltage Three-Phase Current Compensator Using Modular Switching Positions

The objective of this thesis is to present the context, application, theory, design, construction, and testing of a proposed solution to unbalanced current loading on three-phase four-wire systems. This solution, known as the Medium-Voltage Unbalanced Current Static Compensator or MV-UCSC, is designed to recirculate currents between the three phases of adistribution system. Through this redistribution of the currents negative- and zero-sequence current components are eliminated and a balanced load is seen upstream from the point of installation. The MV-UCSC as it operates in the distribution system is presented followed by its effect on traditional compensation equipment. The construction of the MV-UCSC as well as 13.8 kV simulations are then shown. Development of the switching positions required by the MVUCSC is then given followed by a variation on this switching position with the intent to reduce part count. Finally, the testing the 13.8 kV three-phase four-wire, neutral-point-clamped, elevenlevel, flying-capacitor-based MV-UCSC connected directly to the grid is presented

Introductory notes for the Acta IMEKO Special Issue on the “19th Symposium on Measurement of Electrical Quantities” and the “17th Workshop on ADC/DAC Modelling and Testing”

Postprint (published version

Monitoring and Protection of Power Distribution Networks with IEC 61850-9-2 Standard

In the modern power grid, communication plays a vital role in making the system more reliable and secure. The communications network transfers data between different units to a control center or to Intelligent Electric Devices (IEDs) in order to accurately control or protect the modern power system. The paper discussed possible ways to monitor the measured values for protecting the power system according to IEC 61850-9-2 (sample value). The sequence of the process consists of streaming the sample value packet, decoding it, and phasor extraction and filtering, which are discussed here. To validate the research, Sundom Smart Grid was used as a pilot to measure the values converted to digital form (IEC 61850-9-2) and to stream it to the system through a highly secure communications network. To decode the SV packet, two scenarios are presented in the case study, based on processing useful features of the IEC 61850-9-2 standard-based raw data streamed from the SSG, including μPMU in a range of embedded instruments and a real-time simulator. The main result of this paper is an algorithm for analyzing SV packets and determining whether the network is operating normally.©2020 IET. This paper is a postprint of a paper submitted to and accepted for publication in 15th International Conference on Developments in Power System Protection (DPSP 2020) and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at the IET Digital Library.fi=vertaisarvioitu|en=peerReviewed

Interline Unified Power Quality Conditioner for Enhancing Power Quality using FOFPID-based Interleaved CUK Converter

Electrical distribution systems face increased non-linear loads due to using power electronics for the converters. Due to these non-linear loads, the system exhibits PQ problems in the distributed feeders. To enhance PQ problems in the dual feeder, fractional order fuzzy proportional integral derivative controller (FOFPID) is introduced with interline unified power quality (IUPQC) conditioner. IUPQC conditioner includes a distribution static compensator (DSTATCOM), dynamic voltage restorer (DVR) and interleaved cuk converter (ICC). DSTATCOM and DVR are used for compensating the voltages and current in the dual feeders (feeder-1 and feeder-2). Also, ICC monitors the switching between the DSTATCOM and DVR compensators by providing proper power flow. Moreover, the FOFPID controller regulates an input supply from both feeders. The simulation is performed through MATLAB/Simulink platform, demonstrating the robustness of a proposed FOFPID with an IUPQC controller. The performance of a proposed controller is analyzed through two cases for both feeders. Furthermore, the total harmonic distortions (THD) are calculated for the feeder parameters. The proposed FOFPID with IUPQC controller also maintains stability in a dual feeder. Therefore, the entire response shows the functionality and feasibility of a proposed controller

A Novel Integrated Real-time Simulation Platform for Assessing Photovoltaic Penetration Impacts in Smart Grids

For future planning and development of smart grids, it is important to evaluate the impacts of PV distributed generation, especially in densely populated urban areas. In this paper we present an integrated platform, constituted by two main components: a PV simulator and a real-time distribution network simulator. The first simulates real-sky solar radiation of rooftops and estimates the PV energy production; the second simulates the behaviour of the network when generation and consumption are provided at the different buses. The platform is tested on a case study based on real data for a district of the city of Turin, Italy

New Cost-effective Method for Monitoring Wideband Disturbances at Secondary Substation

Modern societies are becoming increasingly dependent on reliable and continuous supply of high quality electricity. Maintaining continuous supply of electricity round the clock depends heavily on the efficient and reliable operation of distribution system components. On the other hand, large-scale power outages are increasing in overhead lines due to extreme weather condition i.e. heavy storms and snowfalls. Distribution network operators (DNOs) are facing considerable network investments in the near future due to the ongoing trend of cabling. At the same time, the long fault location and repair times in aging cable networks set new demands for condition monitoring and fault prevention through preventive maintenance. Partial discharge (PD) monitoring is an excellent way to determine the overall health of the MV components and detect developing faults in underground cables. On the other hand, the proliferation of e.g. distributed generation and electronic loads poses new challenges to maintain the power quality (PQ) in distribution networks. Utilizing network condition and power quality information together would improve the allocation accuracy and benefit-cost ratio of network maintenance and renewals. Thus, the importance of condition monitoring is increasing in the distribution networks to facilitate online diagnostic, preventive maintenance, forecasting risk of failure and minimizing outages.Secondary substations seldom have any remotely readable measurement and control units and the existing measurements in the network are limited to only power quality and MV fault management due to low sampling rate (some kHz). There are also commercially available devices for PD monitoring of underground cables but those capable of continuous on-line monitoring are still relatively expensive and as such, more suited for critical and high risk location. Currently, there are no cost-effective wideband multifunction devices suitable for continuous on-line PD monitoring, PQ monitoring, disturbance recording (DR) and fault location at secondary substation.This thesis proposes a novel cost-effective secondary substation monitoring solution which includes the monitoring system as well as the monitoring concept to measure various quantities at LV and MV side of secondary substation. Additionally, it can be used in fundamental frequency metering and can be used as disturbance recorder as well. It also locates earth fault which is demonstrated as an application of disturbance recording function. The architecture of the monitoring system includes high frequency current transformer (HFCT) sensors for current measurements at MV side, resistive divider for voltage measurements at LV side, filter & amplifier unit and multichannel data acquisition & processing unit. HFCT sensors not only measure PD but also PQ at the MV side of secondary substation, which is a novel approach. Hence, no sensor having expensive high voltage insulations is needed, which makes the solution cost-effective and reliable. The overall concept is tested and verified through prototype systems in the laboratory and in the field. Secondary substation monitoring solution provides a platform on which various monitoring, control and network automation applications can be built

A Novel Integrated Real-time Simulation Platform for Assessing Photovoltaic Penetration Impacts in Smart Grids

© 2017 The Authors. For future planning and development of smart grids, it is important to evaluate the impacts of PV distributed generation, especially in densely populated urban areas. In this paper we present an integrated platform, constituted by two main components: a PV simulator and a real-time distribution network simulator. The first simulates real-sky solar radiation of rooftops and estimates the PV energy production; the second simulates the behaviour of the network when generation and consumption are provided at the different buses. The platform is tested on a case study based on real data for a district of the city of Turin, Italy