Power quality enhancements for IEC 61850

Transcription

1 Power quality enhancements for IEC April 2011 / White paper by D. Cumming, Schneider Electric (CAN) Make the most of your energy

2 Summary Keywords... p 2 Executive summuary... p 2 Introduction... p 3 Global emergence of IEC p 5 Enhancing power quality in p 6 Conclusion... p 8 Keywords IEC 61850, logical nodes, power quality.

3 Power quality enhancements for IEC Executive summuary Today design, deployment, and operation of modern substations are changing significantly. IEC (61850) 1 leads the way, as a notably improved global standard. This paper supports as a worthy vehicle for providing power quality solutions to the industry while examining concepts for enhancing power quality aspects for improved functionality is the result of years of research by leading utility industry experts seeking to provide a universal standard addressing all significant aspects of modern substation communication. 1 IEC 61850: Communication Networks and System in Substations, 2008 White paper l 02

4 Power quality enhancements for IEC Introduction ORIGINALLY centered around automation and protection aspects inside high voltage substations, s guiding principal of using modeling and common services to reduce technical functions into logical pieces (logical nodes) has facilitated branching out into many electrical infrastructure areas. The resulting ability to achieve relatively quick maturity of new functions lends itself well to a vision of the complete modern substation of the future. White paper l 03

5 Power quality enhancements for IEC IEC leads the way as a notably improved global standard White paper l 04

6 Global emergence of IEC Power quality enhancements for IEC The integrated approach to system design and communications has led to IEC emerging as the dominant global utility substation protocol standard. With more than five years of market awareness and two published editions to date, will continue to be heavily prescribed due to the excellent market support from major vendors. Further evidence of this emergence can be seen in the myriad of areas which has reached. Working groups have and are developing extensions of the standard into substationsubstation communications, wind-farms, hydro plants, and device security to name just a few seeks a unified approach, presenting a suite of protocols that are designed to multitask efficiently and provide support for modern engineering workflows in the design, deployment, and operation of electrical utility systems. Fig. 1 shows the traditional substation and the many protocol choices that can exist. Fig. 2 shows the same system as Fig. 1 with a new communications architecture utilizing and Ethernet. Fig. 2 _ Ethernet-based sustation also provides other unique technical benefits superior to traditional communication protocols. These include: File based setup to allow archiving, maintenance, and the potential for high level engineering tools to enable repeatability and ease of deployment. Unified modeling of functions and a common dictionary of terms to provide vendor neutrality and support a strong basis for extension and expansion of the standard in the future. Fig. 1 _ Traditonal sustation protocols. Because Ethernet is the backbone for the architecture, easily deployable technology exists to simplify the substation of tomorrow. Self-description services for automated discovery and potential for system validation at commissioning. The sheer market momentum, coupled with the functional strength of its integrated design and technical potential, mark as the global emerging dominant standard within electrical utility infrastructure. White paper l 05

7 Enhancing power quality in Power quality enhancements for IEC Aspects of power quality analysis and reporting have been included from the beginning in though they are not able to provide a full solution for power quality users. But, because it leverages high bandwidth communications (Ethernet) and an integrated approach to protocol suites and services, can be adapted to provide full support for power quality analysis and reporting applications. Existing Power Quality Support In the current edition of (Edition 2 at the time of writing), there already exist elements of power quality analysis and compliance reporting. These include: Fault record support - Adoption of the COMTRADE 2 fault record standard for providing file-based waveforms and the RDRE (Disturbance Recorder Function) logical node for notification of fault records for clients. File based protocol service - FTP service to provide downloading of COMTRADE fault record data. Modeling for some power quality functions - Logical node support for providing harmonics (MHAI), flicker (MFLK) and imbalanced power calculations (MADV), frequency variation (QFVR), current transient (QITR), current unbalance variation (QUIB), voltage transient (QVTR), voltage unbalance variation (QVUB) and voltage variation (QVVR). Log model service This service can be used to log values from logical nodes in an Intelligent Electronic Device (IED). In the context of power quality, this service could store the power quality statistical values over a power quality survey period. Time synchronization SNTP 3 is called out by the standard and provides potential for millisecond accuracy. Time synchronization is important in order to provide power quality event correlation between devices. These elements are important pieces of power quality but they cannot provide the whole picture. In other words, the current power quality support level in is lacking key features for widely used applications, such as contract based compliance reporting. 2 IEEE Standard Common Format for Transient Data Exchange (COMTRADE) for Power Systems, IEEE standard C37.111, RFC1361: Simple Network Time Protocol (SNTP), White paper l 06

8 Power quality enhancements for IEC Adoption of IEC and EN as a Basis for Enhancing the Power Quality Aspects of In order to bolster the power quality capabilities of the approach should be built on the existing principles of the standard: vendor-neutrality, application relevance, and global market presence. To this end, the obvious choices for power quality applications are the IEC (4-30) 5 and EN standards. These two standards are well established globally and go hand-inhand to provide contractual-based power quality measurement support (4-30) and compliance reporting (EN50160). 3.3 Proposed Power Quality Enhancements to IEC Assuming that the adoption of 4-30 and EN form the basis for the power quality improvements in future versions of the IEC standard, the following additions/ changes should be considered: Modeling for additional power quality functions - Logical Node support should be expanded to include all the required measurements of the 4-30 standard (Class A) and the key data and counters of EN reporting. Time synchronization Time synchronization should be updated to the current standard. In some cases submillisecond time synchronization between devices would be useful for accurate power quality event correlation between devices. At this time IEEE is being considered for future editions of the standard which would provide this functionality. File-based power quality events IED power quality events could potentially be developed in the logical node additions for client reporting. However, it may be useful to provide some kind of file-based power quality method through This method would provide a record sequence of time-stamped power quality events to trace system events between devices (like a cascading protection sequence [based on breaker status] or a waveform based algorithm). File-based support for compliance reporting FTP (public) and File Transfer (61850 specific) services should be modified to provide downloading of power quality compliance reports. In addition, File-based support for compliance reporting could be developed in conjunction with filebased power quality events or as a similar but separate construct. This would provide end user compliance reporting through filebased downloads from the device. Log model service The log model service may require some extension in order to provide meaningful data for power quality applications. 4 EN 50160: Voltage Characteristics in Public Distribution Systems, IEC : Testing and measurement techniques - Power quality measurement methods, IEEE 1588: Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems, White paper l 07

9 Power quality enhancements for IEC Conclusion IEC is a powerful standard. Built on sound engineering principles and technology, it can be leveraged to provide valuable information in power quality analysis, compliance reporting applications, and other similar functions. Using widely adopted power quality standards for measurement and reporting, like IEC and EN 50160, could provide logical key support. By enhancing the logical node support, time synchronization accuracy, and event sequencing with additional quality reporting for end users, IEC can be extended to support many advanced power quality applications. White paper l 08

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