Muhammad Shoaib Almas

SmarTS Lab — A laboratory for developing applications for WAMPAC Systems

At the core of the development of “Smart Transmission Grids” is the design, implementation, and testing of synchronized phasor measurement data applications that can supplement Wide-Area Monitoring, Protection, and Control Systems (WAMPAC). Nevertheless, the development of new PMU data-based WAMPAC applications has been relatively slow. The great potential of WAMPAC systems is being limited by this, and efforts are needed so that new applications can be developed. The slow rate of development of these applications is strongly related to, among other factors, the application development approach used. This article starts by discussing the needs and approaches for developing WAMPAC applications that exploit synchronized phasor measurements, and illustrates how one of these approaches has been achieved. A preliminary work carried out to develop and implement a Smart Transmission System Laboratory (SmarTS Lab), a hardware and software-based system for developing and analyzing “Smart Transmission Grids” paradigms and applications for WAMPAC systems, are described. The laboratorys conceptual architecture and hardware and software implementation are presented, and some of its components are described. Finally, the article illustrates proof-of-concept examples of how PMU data-based applications can be developed.

Over-current relay model implementation for real time simulation & Hardware-in-the-Loop (HIL) validation

Digital microprocessor based relays are currently being utilized for safe, reliable and efficient operation of power systems. The overcurrent protection relay is the most extensively used component to safeguard power systems from the detrimental effects of faults. Wrong settings in overcurrent relay parameters can lead to false tripping or even bypassing fault conditions which can lead to a catastrophe. Therefore it is important to validate the settings of power protection equipment and to confirm its performance when subject to different fault conditions. This paper presents the modeling of an overcurrent relay in SimPowerSystems (MATLAB/Simulink). The overcurrent relay has the features of instantaneous, time definite and inverse definite minimum time (IDMT) characteristics. A power system is modeled in SimPowerSystems and this overcurrent relay model is incorporated in the test case. The overall model is then simulated in real-time using Opal-RTs eMEGAsim real-time simulator to analyze the relays performance when subjected to faults and with different characteristic settings in the relay model. Finally Hardware-in-the-Loop validation of the model is done by using the overcurrent protection feature in Schweitzer Engineering Laboratories Relay SEL-487E. The event reports generated by the SEL relays during Hardware-in-the-Loop testing are compared with the results obtained from the standalone testing and software model to validate the model.

Synchrophasor network, laboratory and software applications developed in the STRONg 2 rid project

This paper presents the activities carried out in one of the work packages of the Nordic Energy Research funded project Smart Transmission Grid Operation and Control (STRONg2rid). The main objective of the work package is to deploy a state-of-the-art software and hardware for developing power system operation, protection, control and automation applications. Several PMUs have been deployed at partner universities and a network of synchrophasors has been set up. In addition the Smart Transmission System Laboratory (SmarTS-Lab) has been established. This laboratory serves as a test-bench to develop and verify smart transmission grid technologies. A software development kit (S3DK) was developed within the project. The S3DK has been used to implement PMU-based applications and deploy them in different targets, including smart phones and tablets. Several tools and software applications which utilize synchrophasor measurements (from the laboratory or the deployed university PMU network) to perform power system monitoring, sub-synchronous power oscillation detection, etc., have been developed and are presented herein.

RT-HIL Implementation of the Hybrid Synchrophasor and GOOSE-Based Passive Islanding Schemes

Real Time Hardware-in-the-Loop (RT-HIL) performance assessment of three different passive islanding detection methods for both local and wide-area synchrophasor measurements is carried out in this article. Islanding detection algorithms are deployed within the Phasor Measurement Unit (PMU) using logic equations. Tripping decisions are based on local and wide-area synchrophasors as computed by the PMU and trips are generated using IEC 61850-8-1 Generic Object Oriented Substation Event (GOOSE) messages. The performance assessment compares these islanding detection schemes for Non Detection Zone and operation speed under different operating conditions. The test-bench demonstrated is useful for a myriad of applications in which simulation exercises in power system CAD software provides no realistic insight into the practical design and implementation challenges. Finally different communication latencies introduced due to the utilization of synchrophasors and IEC 61850-8-1 GOOSE messages are determined.

Experiences with steady-state PMU compliance testing using standard relay testing equipment

This paper presents the results of steady state compliance testing of phasor measurement units (PMUs) from three different vendors in a laboratory environment. Testing is performed by providing three phase voltage and current injections to the VT and CT inputs of the PMUs through Freja-300 stand-alone protection relay test set. Testing is performed according to the standard “IEEE C37.242-2013 - IEEE Guide for Synchronization, Calibration, Testing, and Installation of Phasor Measurement Units (PMUs) for Power System Protection and Control”. The paper discusses the test setup, testing process and overall test results of this project. The limitations of stand-alone testing equipment and recommendations for utilizing real-time hardware-in-the-loop simulation for thorough testing of PMUs are also presented.

Voltage stability monitoring using sensitivities computed from synchronized phasor measurement data

Wide-area early warning systems are dependent on synchrophasor data-based applications for providing timely information to operators so that preventive actions can be taken. This article proposes the use of voltage sensitivities computed from syncrhophasor data for voltage stability monitoring, and a visualization approach that can be implemented in wide-area early warning systems. In order to provide reliable information, synchrophasor data must be pre-processed to extract only the useful features embedded in measurements and correct for errors. Hence, this article also addresses the issue of data filtering and correction, and proposes a filtering methodology for robust voltage sensitivity computation. The methodology is developed considering both positive-sequence simulations for methodology development purposes, and real phasor measurement data from a real-time (RT) hardware-in-the-loop (HIL) laboratory for testing the robustness of the developed approach for use in the control room. The results from both approaches are contrasted against each other, the limitations of the positive-sequence simulation approach for developing PMU-data applications are highlighted and the challenges of working with the RT HIL lab are recognized.

A MATLAB-based PMU simulator

The use of Phasor Measurement Unit (PMU) data in power system operation is of increasing importance. These data are currently used for real-time operation monitoring and off-line analysis. A good understanding of the phasor measurement process is essential for phasor quality analysis as well as for the design of advanced control and protection schemes. In this paper the main computational algorithms involved in the phasor measurement process are illustrated using a Matlab based PMU simulator.

PMU-based real-time damping control system software and hardware architecture synthesis and evaluation

Low-frequency, electromechanically induced, inter-area oscillations are of concern in the continued stability of inter-connected power systems. Wide Area Monitoring, Protection and Control (WAMPAC) systems based on wide-area measurements such as synchrophasor (C37.118) data can be exploited to address the inter-area oscillation problem. This work develops a hardware prototype of a synchrophasor-based oscillation damping control system. A Compact Reconfigurable Input Output (cRIO) controller from National Instruments is used to implement the real-time prototype. This paper presents the design process followed for the development of the software architecture. The design method followed a three step process of design proposal, design refinement and finally attempted implementation. The goals of the design, the challenges faced and the refinements necessary are presented. The design implemented is tested and validated on OPAL-RTs eMEGASIM real-time simulation platform and a brief discussion of the experimental results is included.

Real-time data mediation for synchrophasor application development compliant with IEEE C37.118.2

This paper presents the design and implementation of a IEEE C37.118-2-compliant real-time data mediator, namely BableFish (BF), that facilitates synchrophasor data-manipulation for smart grid applications. The mediator is scalable by virtue of its modular software architecture, and is capable of receiving concurrently synchrophasor data streams from either Phasor Measurement Units (PMUs) or Phasor Data Concentrators (PDCs). The different modules of the mediator and their functional capabilities are discussed. Furthermore, the performance of the mediator is analyzed through several statistical performance stress tests. The mediator facilitates prototyping of wide area power system monitoring and control applications using real-time hardware-in-the-loop simulation, as illustrated with examples in development at KTH SmarTS Lab. Finally, the technical challenges associated with implementation and integration of system-wide synchrophasor solutions for realtime synchrophasor-based applications is discussed.

Analysis of communication network challenges for synchrophasor-based wide-area applications

Wide-area synchrophasor applications inherently depend on the underlying IT and communications infrastructure supporting them. In particular, closed loop control systems for power grid oscillation damping is problematic, as it is a complex mixture of power grid monitoring, communication network properties and overall system stability issues. This article offers a holistic analysis of these fields, proposing a combined requirement on the full system: to keep system delays down to maintain stability. Simulation results to support the analysis findings, also showing how observability of power oscillations is important in combination with system delays related to feedback signals, and finally laying out experimentation plans to be performed in the lab on a complex power-grid model with real PMUs, communication network and controllers interacting with the SmarTS Lab real-time hardware-in-the-loop simulator platform.