Mini S. Thomas

Design, development, and commissioning of a supervisory control and data acquisition (SCADA) laboratory for research and training

This paper reports a state-of-the-art Supervisory Control and Data Acquisition (SCADA) Laboratory facility for power systems at Jamia Millia Islamia, New Delhi, India. It has been designed to function as a research and training center for utilities, faculty members, and students. This paper covers the design, commissioning, and functioning of the SCADA/EMS laboratory facility, based on distributed-processing technology. The SCADA laboratory will provide hands on experience to students and practicing engineers and will give them an insight into the contemporary SCADA systems. This lab is the first of its kind to be functional in India.

Reliable, Fast, and Deterministic Substation Communication Network Architecture and its Performance Simulation

A highly reliable, fast, and deterministic communication network is required to support time-critical real-time monitoring, protection, and control functions of the substation automation systems (SAS). This paper proposes an Ethernet-based logical architecture for the substation communication network (SCN). Improved reliability, availability, and survivability of the SAS are demonstrated through the unique architectural features of this SCN, whereas the end-to-end (ETE) time-delay performance of the SCN architecture is evaluated with the help of simulation. The optimized network engineering tool modeler is used for modeling and simulation of the various nodes of the SCN and the communication traffic according to IEC 61850, the International Electrotechnical Commissions (IEC) standard for Communication Networks and Systems for Substation.

Substation Communication Networks Architecture

There is a need for fool proof architecture of the substation communication network (SCN) for reliable, fast and deterministic operation of the automation functions within a substation, to ensure the reliability, availability and survivability of the geographically distributed complex power network. This paper presents different types of Substation Communication Network architectures and analyzes their performance, which is intended to help the power utility personnel, to plan and build a substation automation system (SAS), with a fool proof substation communication network having desirable real-time performance characteristics to support the functions of a SAS. The reliability aspect of the SCN is demonstrated through their architecture and the adopted methods of communication. Modeling of various real-time communication network traffics within the substation is done according to IEC 61850: Communication Networks and Systems for Substations Standard and OPNET Modeler is used for Simulation of the performance analysis.

Fuzzy-genetic algorithm for pre-processing data at the RTU

Uncertainties are always present in the data captured at the remote terminal unit (RTU) in a power system. In this paper, it has been demonstrated that pre-processing the data with a fuzzy-genetic algorithm at the RTU will reduce the uncertainty and vagueness in the measurands. The initial population for the genetic algorithm is generated with assumed fuzzy functions. These functions are optimized using the theory of reproduction, cross over and mutation. The result shows that the fuzzy-genetic algorithm gives better results than the other methods available. It is also observed that the fuzzy-genetic algorithm is easy to apply to the output fuzzy solution rather than to the input fuzzy function.

Fuzzy approach to fault classification for transmission line protection

This paper presents a scheme for real time fault location and classification on transmission lines using fuzzy logic technique. The protection algorithm is based on the travelling waves present on major transmission lines after the incidence of a fault. The time interval between the initial travelling wave propagated from a fault and a later wave resulting from a reflection at the fault position is used to find the location of the fault. A possible application based on modal analysis to detect the type of fault is also proposed. This paper shows that a fuzzy approach can be useful in transmission line protection, whenever fuzzy decisions have to be undertaken. Simulation results are used to illustrate the basic features of the performance of the new scheme on a 220 kV transmission line.

Design, Development, and Commissioning of a Substation Automation Laboratory to Enhance Learning

Automation of power systems is gaining momentum across the world, and there is a need to expose graduate and undergraduate students to the latest developments in hardware, software, and related protocols for power automation. This paper presents the design, development, and commissioning of an automation lab to facilitate the understanding of substation automation (SA). The laboratory has relay intelligent electronic devices (IEDs) that support IEC 61850 protocol, a universal secondary test kit for testing the relays, a protocol converter that can be programmed and can handle a large number of power automation protocols, a Global Positioning Systems (GPS) clock for time synchronization, and all related software. In this paper, the retrofitting of the latest relay IEDs with the existing control center software has been demonstrated. The commissioning process and the experimental setup of the SA laboratory have also been described. A post-training evaluation emphasizes that the student learning experience is helping students to gain a better understanding of the theory and to have better career prospects in power automation. The SA laboratory, which demonstrates all aspects of substation automation, is being used extensively for research and training in this emerging field.

Islanding detection using decision tree approach

Islanding occurs when part of a distribution network is disconnected from the rest of the power system but continues to be energized by a distributed resource (DR). Failure to trip the islanded DR can lead to serious problems for this DR and the connected loads. One method of islanding detection utilizes and combines different system parameters by using data mining technology and a multifunction software model to extract information from these data sets. It also detects the threshold settings for the islanding relays. Using the same methodology, an attempt has been made in this study to simulate the network and obtain the threshold settings by selecting a new set of parameters. Good accuracy was observed when compared to the data mining approach in spite of choosing a different set of parameters. The main advantage is parameters chosen are easily measured and the software tools used are readily available.

Comprehensive Control for Microgrid Autonomous Operation With Demand Response

Several situations in a microgrid (MG) cause unbalances leading to voltage and frequency variations. Conventionally MG power balance is ensured by storage battery units along with unscheduled load shedding. This paper presents control and management strategies to coordinate MG resources including generation, smart electric vehicles, and loads for frequency and voltage regulation to achieve optimal autonomous operation. MG control is designed in two layers of network, i.e., neighbour area network (NAN) and house area network (HAN). MG central controller operates at NAN layer, local load controllers operate at HAN layer, and smart electric vehicle controllers operate at both NAN and HAN layers. Two strategies—comprehensive control (CC) and vehicle aided CC—are developed and implemented in 11/0.4 kV urban residential four-feeder distribution system operating as MG. Both strategies enable calculative load manipulation for demand response (DR) considering customer load priority, thus maximizing customer satisfaction. The simulation results validate the proposed strategies providing frequency regulation and DR for MG autonomous operation. The proposed control and management strategy also provides an on-line tool for household maximum demand allocation and load management.

Modeling and Testing of Protection Relay IED

The analysis of protection relay operation is very important in order to determine the cause of unexpected behavior of the relay. This is useful in identifying problems with the relay settings or with the implemented protection algorithm that may result in an undesired operation and system disturbances. If the conclusion is that the relay IEDs did not operate as expected, the user may change the settings and test the relay by replaying the recorded fault waveform through a test device to check the performance. The process of analysis is complicated and requires special equipment, as well as a relay IED to implement the modifications and to test the new configuration. The main objective of this paper is to test and verify the performance of a protection relay IED through off-line and on-line tests. The results show that these testing tools are very useful during the commissioning and operation of a protection relay IED.

IEC 61850 Substation Communication Network Architecture for Efficient Energy System Automation

Abstract High-speed peer-to-peer IEC 61850-8-1 GOOSE and IEC 61850-9-2 sampled values based information-exchange among IEDs in modern IEC 61850 substations have opened the opportunity for designing and developing innovative all-digital protection applications. The transmission reliability and real-time performance of these SVs and GOOSE messages, over the process-bus network, are critical to realize these all-digital IEC 61850 substation automation systems (SASs) protection applications. To address the reliability, availability, and deterministic delay performance needs of SAS, a novel IEC 61850-9-2 process-bus based substation communication network (SCN) architecture is proposed in this article. Reliability of the proposed as well as the traditional process-bus based SCN architectures is evaluated using the reliability block diagram (RBD) approach. Network components are modeled, and end-to-end (ETE) time-delay performance is also evaluated for all-digital protection applications running on the SCN architectures simulated in the OPNET modeler platform. The reliability and performance results of the proposed architecture compared to the traditional architectures confirmed its highly reliable, fast, and deterministic nature.