Mark Adamiak

Development and Implementation of a Synchrophasor Estimator Capable of Measurements Under Dynamic Conditions

The classical two-parameter Fourier algorithm for computing synchrophasors is appropriate when the underlying voltage and current waveforms are sinusoids with constant amplitude and phase angle and with a frequency equal to the assumed value. Synchrophasor measurements, however, are applied in power systems to track dynamic conditions where, by definition, currents and voltages, though resembling sine-waves, exhibit changes in their magnitudes and vectorial positions. This paper presents a novel algorithm for estimating synchrophasors under such dynamic conditions. In contrast to the classical Fourier algorithm, our model is a complex Taylor expansion, yielding several parameters in the model to be estimated. Four- and six-parameter models are presented corresponding to first and second order Taylor expansions. This paper derives a compensation method for canceling the error in the classical Fourier algorithm that arises under dynamic conditions, shows comparative simulation and test results and describes an efficient implementation. Application of the error cancellation method to other phasor algorithms and extending the technique to higher order Taylor expansions, are discussed. Implementation of synchrophasor measurements on protection and control intelligent electronic devices (IEDs) is discussed, and solutions are presented that allow for secure integration.

IEEE PSRC Report on Global Industry Experiences With System Integrity Protection Schemes (SIPS)

This paper is a summary of the IEEE Power System Relaying Committee report on the System Integrity Protection Schemes (SIPS) survey. The SIPS role is to counteract system instability, maintaining overall system connectivity, and/or to avoid serious equipment damage during major system events. The survey describes industry experiences with this category of protection schemes applied to protect the integrity of the power system. It is designed to provide guidance for SIPS users and implementers based on surveyed operating practices and lessons learned. The survey includes a global participation through the comprehensive effort of IEEE and CIGRE.

JEC 61850 - A Practical Application Primer for Protection Engineers

This paper reviews concepts proposed by the IEC 61850 standard; protection and control (P&C) aspect in particular. The standard describes building blocks meant to facilitate the general idea of migrating traditionally hard-wired P&C connections and configurations into the realm of software, while opening considerable opportunities for engineering and labor savings. The underlying principle is that the newly introduced complexity resides in software, and therefore, new software tools will reduce or eliminate some of it, simplifying both the engineering and deployment, thus resulting in a substantial net gain. IEC 61850 has received considerable attention in recent years, but vast majority of publications are written around the theme of the intelligent electronic device (IED), and rest at introducing the concept, reviewing selected details of IED implementations, and focusing on anticipated advantages. This paper is written for a traditional P&C engineer and reviews important practical questions that need to be answered, solutions worked out, and tools developed before the IEC 61850 concept could see its all-inclusive implementation

Synchrophasors: A primer and practical applications

Although the concept and definition of Synchrophasors dates back to 1980, the combination of 2nd generation IED platforms and power system needs has brought the technology into high-visibility in the electric power industry. As synchrophasor technology has matured, nuances of the measurement of a synchronized phasor have been identified and the details of ldquohowrdquo a phasor is defined, synchronized to absolute time, reported, and communicated have subsequently been re-codified int he recently revised IEEE standard: Synchrophasors for Power Systems - C37.118. This paper reviews the concept of the synchronized phasor in light of the IEEE C37.118 standard. Specifically, details of an ldquoun-correctedrdquo Fourier based phasor during off-nominal frequency conditions are presented as well as techniques for correction to meet the Synchrophasor standard. The need for IED input transformer and filter characterization / correction is presented. Simulations of various system transients and their phasor response are presented - specifically, the response of synchrophasor calculation to dynamic system conditions. Finally, this paper reviews application of synchrophasors on the SRP system today as well as plans and needs in the future.

Reliabilty of protection systems (what are the real concerns)

Protection Systems have a significant role in maintaining the stability and reliability of the electric power grid. Their optimal performance plays a vital role and becomes more critical when the power system is operating near its limits. Protection Systems are used to detect and isolate faults or to arrest adverse conditions that occur on the grid. Subsequently, misoperation of these systems must be kept to a minimum. This paper discusses protection applications and reliability considerations, and methods such as Synchrophasor monitoring of system conditions that can be incorporated into protection schemes to reduce problems stemming from a variety of hidden failure modes and increase the effectiveness and reliability of Protection Systems. The impact of Protection System failures on dependability and security is discussed. Failure modes initiated by Calculation of Settings and Modeling Errors, Firmware issues, and Hardware failures will be analyzed. The various components of the Protection System are described and plausible failures of these components are presented. The use of separate but equivalent (redundant) protection systems is presented to illustrate methods that could increase reliability of the protection systems. This includes a discussion concerning same or different manufacture of protective relays. The probabilities of these failure modes will be presented. The effect of the new NERC guidelines on protection system redundancy is evaluated.

High-Speed Control Scheme to Prevent Instability of A Large Multi-Unit Power Plant

Unintended loss of a major power plant can cause substantial strain on the remaining generating resources and lead to local system instability and/or generate oscillations with impact to the overall bulk power system. In the continuing quest to improve the availability of the generation supply and in order to meet the more stringent electric coordinating council reliability criteria, power companies and grid operators are focusing on System Integrity Protection Schemes (SIPS) that can detect and react on events leading to potentially unstable power system conditions. One such situation occurs when severe disturbances occur on transmission line exits from large multi-generator power plants. Based the disturbance severity, the typical results are intensive swings or loss of plant synchronism which will lead into loss of the entire generation complex either by out-of-step protection, or unit shutdown by protective devices reacting to voltage dips at auxiliary buses. By quickly detecting the destabilizing conditions, preemptive actions can be taken to preserve the plant and minimize the extent of the disturbance and subsequent effect on the power grid. Such SIPS offer added advantages under normal operating conditions for scheduled transmission line outages, and allow full power operation with a line out of service. This paper discusses a control solution based on implementation of high-speed SIPS. The control strategy results from transient stability analysis for various types of transmission line faults, including delayed faults caused by complete and partial breaker failures. Different types of faults and transmission outlet line outage conditions for various system and plant initial conditions are investigated and options for mitigation are recommended. The discussion includes stability requirements, alternative actions and algorithms, SIPS components, the methodology for obtaining arming settings, interaction with the existing protection schemes, and effect of a switchyard topology. Technical implementation considerations such as system design, architecture, measures for reliable and secure operation, synchrophasor capture, event capture, performance under missing or conflicting information, and testing are discussed.

Design of a Priority-Based Load Shed Scheme and Operation Tests

Many large industrials operate internal cogeneration systems to provide a substantial portion of their own power and to use the resulting output heat as part of their industrial process. Depending on the amount of cogeneration, on loss of connection to the main grid or instability of the grid, these industrials may have the option of supplying all internal electrical loads from the cogeneration or rather shedding a portion of the load in order to maintain plant stability. In order to maintain and maximize plant operations during either an islanded condition, a severe (and dropping) underfrequency condition, or a prolonged undervoltage condition, a load shed scheme needs to dynamically monitor the load-generation unbalance in the plant and, upon detecting or determining any of the above conditions, needs to quickly initiate shedding of the optimal amount of load based on a user-determined priority schedule. Examples of an actual load shed test are shown and analyzed.

Optimizing Wide Area Measurement System architectures with advancements in Phasor Data Concentrators (PDCs)

Large scale deployment of Wide Area Measurement System (WAMS) is underway at several major power utilities around the globe. This is influencing several activities and discussions at international standard associations (IEEE/IEC) and meetings (NASPI/CIGRE/PSRC) to devise the effective but optimum WAMS architecture. This paper presents some of the recent advancements in Phasor Data Concentrator (PDC) technology to achieve fit-to-purpose WAMS architecture. The presented guidelines can be used to reduce the network bandwidth requirements as well as PDC latency. In addition, this paper also discusses various desired features to handle communication network contingencies, e.g. GPS fail, loss of PMU communication, PMU streams with different data rates and different latency; lost synchrophasor data; diagnostics and their notification at upstream devices, etc.

An overview of the new IEC 61850 synchrophasor publish-subscribe profile

The continuing development and implementation of Synchrophasors throughout the world has given rise to multi-utility sharing of these synchronized measurements, new applications using these measurements, and the need for secure transmission of such. To this end, the IEC TC57 Working Group 10 has undertaken the task to identify the communication requirements for these synchronized measurements and to develop a communication profile to effectively meet the identified requirements. This paper starts by reviewing the identified requirements, including those defined in the North American SynchroPhasor Initiative Network (NASPINet) document, as well as a number of other “use” cases. A description of the resulting profile to meet these requirements is then presented. Of particular note is the use of existing IEC 61850 constructs, such as GOOSE and Sample Values and the XML-based configuration tools that already exist to populate such. The issue of transmitting large synchrophasor datasets will be discussed as well as the management of redundant messages by the subscriber. The paper will also review the complete security suite that is part of the profile including message authentication, data encryption, and key management among the various subscribers of the message. Operational needs in the larger network will be discussed. Finally, a comparison between the existing C37.118 communication profile and IEC 61850 90-5 will be presented.

Practical applications of Ethernet in substations and industrial facilities

This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard throughout the world is Ethernet and the worldwide investment into this technology dwarfs that of investment into any other LAN standard. Speed, fiber support, multiple services and protocol support, and the emergence and usage of the IEC61850 protocol have resulted in an increase in the installation of Ethernet within substations and industrial facilities. There are many practical aspects associated with the application of Ethernet within the substation and industrial facility. This paper will address Ethernet fundamentals and will attempt to cover the most common elements of an Ethernet architecture from media selection, requirements for protective relaying systems, managed Ethernet Switch functions and terminology relevant to the protection relay engineer (such as VLAN, RSTP and QoS), network topology (ring, star, mesh, redundancy) and high speed recovery of redundant ring networks. Architectures for different applications will be reviewed, such as SCADA and GOOSE messaging. The intent of this paper is to educate the non-IT person, such as the protective relay engineer, on Ethernet fundamentals that are important to protective relaying applications.