Relay in the loop test procedures for adaptive overcurrent protection

Doctor of PhilosophyElectrical and Computer EngineeringAnil PahwaNoel N. SchulzMicrogrids with distributed generators have changed how protection and control systems are designed. Protection systems in conventional U.S. distribution systems are radial with the assumption that current flows always from the utility source to the end user. However, in a microgrid with distributed generators, currents along power lines do not always flow in one direction. Therefore, protection systems must be adapted to different circuit paths depending on distributed generator sites in the microgrid and maximum fuse ampere ratings on busses. Adaptive overcurrent protection focuses on objectives and constraints based on operation, maximum load demand, equipment, and utility service limitations. Adaptive overcurrent protection was designed to protect the power lines and bus feeders of the microgrid with distributed generators by coordinating fuses and relays in the microgrid. Adaptive overcurrent protection was based on the relay setting group and protection logic methods. Non-real-time simulator (NRTS) and real-time simulator (RTS) experiments were performed with computer-based simulators. Tests with two relays in the loop proved that primary relays tripped faster than backup relays for selectivity coordination in the adaptive overcurrent protection system. Relay test results from tripping and non-tripping tests showed that adaptive inverse time overcurrent protection achieved selectivity, speed, and reliability. The RTS and NRTS with two relays in the loop techniques were described and compared in this work. The author was the first graduate student to implement real-time simulation with two relays in the loop at the Burns & McDonnell - K-State Smart Grid Laboratory. The RTS experimental circuit and project are detailed in this work so other graduate students can apply this technique with relays in the loop in smart grid research areas such as phasor measurement units, adaptive protection, communication, and cyber security applications

Heat gain from power panelboard

Master of ScienceDepartment of Electrical and Computer EngineeringAnil PahwaWarren N. WhiteThis thesis focuses on estimating the power loss from power panelboards by means of power loss models. The model is intended to be used by HVAC engineers to help estimate building heat loss. While McDonald & Hickok (1985) did not report power losses for power panelboards, Rubin (1979) did. These publications present the power losses of electrical devices at rated loads in tables. In this thesis, the models for electrical devices are created and used, instead of tables, to estimate power losses. The use of curve fit models presents a convenience in calculation of power losses. Breaker, fusible switch, and motor starter power losses presented by McDonald & Hickok (1985) and Rubin (1979) were updated using manufacturer published data, technical papers, industrial standards, and test samples. Test, manufacturer, and analytical model data are collected and power loss curve fit models are created for breakers, fusible switches, motor starters, and bus bars with enclosures. The panelboard power loss is calculated as the sum of partial power losses of the component electrical equipment, i.e. breakers, fusible switches, motor starters, and bus bars with enclosures used in power panelboards. A power loss model for main breaker and fusible switch power panelboards are created based on the sum of breaker, fusible switch, motor starter, and bus bars with enclosure power loss models. The main breaker and fusible switch power panelboard power loss models are used in a heat loss example. It is shown that power panelboard power losses can be significantly overestimated when calculated with one of the methods currently used (Rubin, 1979). This can result in erroneous sizing of HVAC equipment

Electrical substation grid testbed for DLT applications of electrical fault detection, power quality monitoring, DERs use cases and cyber-events

Electrical utilities continue to deploy more intelligent electronic devices (IEDs) inside and outside electrical substation, and are associated with customer-owned distributed energy resources (DERs). The integrity and confidentiality of data from these IEDs, like power meters and protective relays, is crucial. Blockchain technology could improve the resilience of microgrids by improving the security of data sharing. The penetration of customer-owned DERs (renewable energy sources) and the increasing deployment of IEDs can lead to integrate power system applications with Distributed Ledger Technology (DLT). In this study, we implemented the electrical faulted phase detection and power quality monitoring algorithms with a Cyber Grid Guard (CGG) system using DLT. In addition, the DERs (wind turbine farms) use case and protective relay cyber-event tests were assessed, by using the CGG system with DLT. In the experimental model, the testbed was created by using a real-time simulator and CGG system with power meters/ protective relays in-the-loop. The data collected from the CGG system and IEDs were compared with the same time stamp source. These results had shown the successful assessment of protection, control and monitoring applications using a CGG system with DLT. In the future, the ESGT with DERs and the CGG system will be used in other power system applications, based on implementing smart contracts between electrical utilities with customer-owned DERs