The Use Of New Technologies

Published Date: 02 Nov 2017

Literature review

2.1 Introduction

This chapter presents the thesis literature review, a brief look at the IEC60044-7, IEC60044-8 and IEC61850 standard. Focusing on measurement, we look at the evolution of substation systems, from systems using Conventional Transformers (CT) to Non-Conventional Transformer (NCIT), the introduction on smart sensor nodes within a substation environment and IEC 61850-9-2 interface for communicating measurements information from primary plant to secondary plant. We also attempt to outline the benefits and challenges of implementing a data acquisition node (merging unit) for the transmission of measurements from primary plant to control plant.

In the literature review we looks at papers outlining the main problems and dangers of using conventional transformer protection systems, need for change towards the non-conventional transformer protection schemes, NCIT communication interfaces and the benefits of using NCIT. We also look at the need to standardize the communication interfaces to NCIT and introduce smart sensor nodes to interface non-conventional transformers to secondary plant according to IEEE 1541.

We also look at time synchronization requirements for measurements published from a sensor node, time synchronization implementation challenges and Precision Time Protocol (PTP) clocks and PTP time distribution as a possible solution to the one pulse per second requirement for publish measurements from a sensor node.

Finally we look at the IEC 61850-9-2 standard and the information that should be contained within the published measurement carrying message, the structure of the published message and outline what will be the structure of out partial simulation of a sensor node.

Paper/standards

Purpose

Objectives

Results/Observations/ Conclusions

Summary and Comments

Non-Conventional transformers

IEC 60044-7 Instrument transformer

(Electronic voltage transformers)

SANS 60044-7, September 2007

Standard for instrument voltage transformers

standard dedicated to electronic voltage measurements

Introduction of standardised AC and DC voltage instrument transformers, Including subparts such as sensing devices, signal treatment, A/D conversion and interfacing

IEC 61850-9-1 and 61850-9-2 also recognize the data structure outlined in the 60044-7 standard, and expanded to also permit an Ethernet physical layer with the same overall data structure.

IEC 60044-8 Instrument transformer

(Electronic current transformers)

SANS 60044-7, September 2007

Standard for instrument current transformers

Standard dedicated to the electronic CT

Introduction of standardised AC and DC current instrument transformers, Including subparts such as sensing devices, signal treatment, A/D conversion and interfacing

IEC 61850-9-1 and 61850-9-2 also recognize the data structure outlined in the 60044-8 standard, and expanded to also permit an Ethernet physical layer with the same overall data structure.

"Electronic Voltage and Current Transformers Testing Device" by Feng Pan, Ruimin Chen, Yong Xiao and Weiming Sun

18 January 2012

To describe testing methods for instrument transformers, including

electronic EVTs, ECTs with both analogue and digital outputs

The objective is to develop a testing prototype to measure the ratio error and phase error of the

transformer under test

In this paper, a testing device for ECT and EVT has been introduced and the metrological characterization of the device has been discussed. The device is based on the digital signal processing technology, which can test both analogue and digital outputs

In this paper a comparison method is used to test the output of a transformer publishing SV and the output of the reference transformer when the same signal is applied to their primary.

"Impact of Optical Instrument Transformer Characteristics on the Performance of Protective Relays and Power Quality Meters", by: Mladen Kezunovic, Fellow, IEEE, Levi Portillo, George Karady, Fellow, IEEE, and

Sadik Kucuksari, Student Member, IEEE

2006

To evaluate and quantify the influence of optical current transducers characteristics on protective relay performance, and defines criteria and procedure for evaluating the influence of OIT characteristics on power quality meter performance

The purpose of this paper was to evaluate the influence of optical instrument transformers on the performance of protection and power quality metering IEDs

Using of simulation combined with statistical analysis, it was shown in this paper that the influence of NCIT on powers systems can be quantified and the results show that the use optical transducers is expected to positively influence the performance of protection and control IED.

This paper shows the importance of testing systems to enable testing of the optimization of your system when using NCIT. The simulation conducted incorporate power network and instrument transformer models. Simulation of measurements from the instrument transformer was important in the analysis on NCIT’s.

"Application of Non-Conventional Voltage and Currents Sensors in High Voltage Transmission and Distribution Systems", by Dr. Joachim Schmid

and Dr. Kerstin Kunde

investigates the use of new

technologies for current and voltage measurement

especially in high voltage equipment

To evaluate and quantify the influence of optical current transducers characteristics on protective relay performance, and defines criteria and procedure for evaluating the influence of OIT characteristics on power quality meter performance

No tests conducted. In conclusion, low power current transformers with voltage output and resistive-capacitive voltage dividers are non-conventional instrument transformers with well-known measuring principles. These devices can be very well combined with a standalone merging unit, which is providing a digital interface according to IEC 61850.

The benefits of NCIT:

a) Avoiding parallel copper wires to connect the instrument transformers to the secondary equipment.

b) Low power instrument transformers have a wide linearity and need smaller cross section of the cores.

c) One design can be applied for metering as well as for protection purposes.

"Current Differential Protection based on Non-Conventional Instrument Transformer and IEC61850" By: Kun Liu, Xinzhou Dong and Zhiqian Bo2

To look at the application of NCIT and interfacing of IEC 61850 merging unit in current differential protection schemes

Analyses of the time delay of transferring sampled values from NCIT to current differential relay in IEC61850 based substation, outline the non-deterministic time delay problem.

A novel method based on

Phase-Locked Loops (PLL) technology to implement the time synch between MU and protection IEDs developed and compared with the method adopting the absolute accurate time provided by GPS. It is provided that the PLL method can considerable reduce computation overhead in hardware.

This paper outlines some of the applications of merging unit in a substation automation system and how novel techniques can be applied to resolve certain aspects in a substation automation system.

Smart sensors nodes/interfaces

"The IEEE 1451.4 Standard for Smart Transducers" by John Mark, Kistler Instrument Corporation and

Paul Hufnagel, Kistler Instrument Corporation Secretary, IEEE 1451.4 Standard Working Group

September 2004

To look into the IEEE 1451.4 templates, the set of properties or values that describe key

characteristics of the transducer

The objective of this paper was to explore the IEEE P1451.1 and IEEE P1451.2 as the standards that define common object model description for transducers and transducer electronic data sheet (TEDS), smart transducer interface module and transducer independent interface.

IEEE 1451.4 templates are a set of properties or values that describe key characteristics of the transducer in an object orientated model with a network capable application processor (NCAP) for network interfacing. TEDS are described in a template description language (TDL). TDL provides several ways to encode values into the TEDS memory with varying degrees of precision and compression.

The paper looks at the roadmap of transducer standards from IEEE P1451.1 until IEEE P1451.4 was accepted as a full-use standard by the IEEE Standards Association, May 14,

2004. It further discusses the modelling of smart transducer nodes and smart nodes network interfaces

"Smart Interfaces for Sensors" By: James Wiczer

Analysis of the strengths and weaknesses of smart sensor technology and strategies for successful implementation.

To create an awareness of smart sensor technology, whilst raising the economic implication and deployment cost of smart sensors.

a) In conclusion real-world examples of smart sensor technologies that suffered from significant economic and technical feasibility challenges.

b) Real-world example of a smart interface applied to an unenhanced sensor to create a functioning smart sensor unit.

From the (a) and (b), the benefits of smart interface provided by the IEEE 1451.2are outlined

This paper provides a good base for designers and system developers to access the feasibility of employing smart sensor technology in their system. Furthermore the benefits of using IEEE 1451 complaint sensors when deploying smart sensors.

Time synchronization methods

"IEEE 1588/PTP: The Future of Time Synchronization in the Electric Power Industry" By: Bernhard Baumgartner, Christian Riesch, Manfred Rudigier

To present a general introduction to the PTP standard and its novelties in comparison to existing time synchronization and distribution.

Provide scenarios and implementation examples of PTP’s in power utilities, focusing on the infrastructural requirements to allow a successful deployment of PTP time synch in such substations

In summary, if the entire infrastructure of a network is IEEE 1588 compliant all propagation delays inside the network are automatically compensated. The IEEE 1588 standard defines an entire system of different PTP clocks, such as master clocks, transparent clocks, boundary clocks and ordinary clocks, which ensures that all timing needs in a complex network can be addressed

Integration to IEC 61850 is ensured by IEEE C37.238, which especially addresses the needs and requirements of the electric power industry. IEEE 1588 is also essential in providing sub millisecond time synchronization for merging units

"Use of Precision Time Protocol to Synchronise Sampled Value Process Buses" By: David M. E. Ingram, Senior Member, IEEE, Pascal Schaub, Member, IEC TC57 WG10 and Duncan A. Campbell, Member, IEEE

Year: 2011

PTPv2, to examine grandmaster holdover and recovery from loss of GPS synch.

Observe the effects of outages in timing system on SV process bus application

Tests were conducted with commercially available PTPv2 and it was demonstrated to be a viable method of providing time synch for a sampled value process bus using IEC 61850-9-2, in particular 9-2LE. Propagation delays are compensated for by PTPv2, providing benefits over various other 1PPS systems.

From the tests conducted PTPv2 was proved as a viable source of 1PPS timing signals. Some of the tests examined steady-state and dynamic performance of clocks when recovering from contingencies.

"Performance Analysis of PTP Components for IEC 61850 Process Bus Applications" By: David M. E. Ingram, Senior Member, IEEE, Pascal Schaub, Duncan

Year: 2012

Performance evaluation of commercially available PTP devices from various manufacturers. Explore the effect of SV traffic on PTP performance.

To provide a series

of tests that can be used by system designers to evaluate timing components in SV process bus

Results from testing PTP performance in the presence of SV process bus traffic demonstrate the benefit of a "bottom up" component testing approach combined with "top down" system verification tests.

The results from the experiment show that the clocks selected for a substation timing system influence its performance of merging units and should be one of the major consideration when implemented in SAS

"Implementing Robust Time Solutions for

Modern Power Systems" By Edmund O. Schweitzer, III, David Whitehead, Shankar Achanta and Veselin Skendzic

Schweitzer Engineering Laboratories, Inc.

paper examines various time sources available for use in

power system applications, such as GPS, NTP, SNTP and IEEE 1588

To analyse and evaluate each time source’s accuracy, distribution methods, applications, costs, benefits, and weaknesses.

In conclusion this paper states that several time sources and distribution methods available today to provide adequate and accurate time synchronization for power systems. With the evolution of new time-distribution methods, this paper proposes a robust time system such as PTP.

Having the analysed various time synchronization methods in this paper the authors have established trade-off between cost, performance and accuracy is established. PTP provide an accurate and easily distributed time synchronization method but are still fair costly for the time being.

IEC 61850 substation system

"Power System Real Time Simulation Testing Using IEC 61850" by Yogesh Sonawane, Pankaj Patil, N.D.Sonawane and Sayali Sonawane

To look at the latency and deterministic performance appropriate for an IEC 61850 real-time simulation.

This paper introduces real time digital simulation testing that includes the use of IEC 61850. A list of advantages for using IEC 61850 in simulation testing is presented along with key design criteria used when incorporating IEC 61850 into a real time digital simulator.

An IEC 61850 messaging capability was successfully developed for the RTDS Simulator. The hardware implementation, referred to as the GTNET, is capable of providing both binary input and output as well as sampled value output for voltage and current signals

There are a number of advantages to using an IEC 61850 interface for simulation testing compared to using traditional electrical interfaces. One of the goals of IEC 61850 is to provide a comprehensive set of functions to replace proprietary protocols; simulation testing can be performed on products from different vendors using only the IEC 61850 protocol.

"Integration of IEC 61850 GSE and Sampled

Value Services to Reduce Substation Wiring" by David Dolezilek, David Whitehead, and Veselin Skendzic, Schweitzer Engineering Laboratories, Inc.,

To describe the impact of new local and

wide-area protection, control, and monitoring concepts based on system-wide exchange of real-time state and measurement

information

Emphasise the implications IEC61850 on substation architecture and the benefits derived from multivendor interoperability and the physical

expanded use of fiber-optic networks

Alternate methods requiring less labour and shorter deployment times are necessary.

The solution to this problem lies in wire reduction, which leads to smaller footprints, and prefabricated solutions based on international standards but flexible enough to be customized for individual project requirements.

As shown in this paper, the smart grid initiative is expected to have a profound effect on how we design, build, and maintain power system protection and control resources

"Multicast Traffic Filtering for Sampled Value

Process Bus Networks", by David M. E. Ingram, Pascal Schaub and Duncan A. Campbell

The purpose of this paper was to look at a system of network traffic segregation using a combination of Virtual LAN (VLAN) and multicast address filtering using managed Ethernet switches.

Asses the challenges when implementing a sampled value process bus due to the large amount of network traffic. Propose a method to map substation plant reference designations to multicast address ranges enabling engineers to determine the type of traffic and location of the source by inspecting the destination address.

Two levels of traffic segregation are recommended.

The first is through the use of VLAN filtering (802.1Q) to prioritise the protocols and their application, and the second level is to use multicast address filtering (802.1D) to limit the flow of information within the particular VLAN. This approach is consistent with the draft Network Engineering Guidelines that will be published as IEC TR 61850-90-4.

This paper emphasise the importance of multicast address segregation conformance with the IEC 61850-9-2 standard. It also proposes a segregation method based not only on multicast and VLAN address but on the importance of the information to be shared.

"IEC 61850-9-2 Process Bus and

It’s Impact on Power System Protection and Control Reliability" By: Veselin Skendzic, Ian Ender, and Greg Zweigle, Schweitzer Engineering Laboratories, Inc.

Analyse the Sampled Value (SV) Process Bus concept introduced by the IEC 61850-9-2 standard

To look at the Merging Unit Concept, analyses the protection

system reliability in the process bus environment, and

proposes an alternate approach that can be used to successfully

deploy this technology

An evaluation of process bus substation reliability by calculating the Mean Time Between Failure (MTBF) using various architectures was conducted. Distributed function architecture is proposed to minimise the MTBF of SAS implementing process bus.

An important property of the SV-based process bus that is evident is from the investigation conducted is high bandwidth requirement and high processing speed required from the process bus and merging unit respectively. These features are imperative to the implementation of a process bus system but fall outside the scope of this project.

"Test and Evaluation System For Multi-Protocol

Sampled Value Protection Schemes" By: David M. E. Ingram, Senior, Duncan A. Campbell, Pascal Schaub, and Gerard Ledwich

To describe a specific test and evaluation system that

uses real time simulation, protection relays, PTPv2 time clocks

and artificial network impairment that is being used to investigate

technical impediments to the adoption of SV process bus systems by transmission utilities

To identify limits of a digital process bus, especially when sampled values and NCITs are included.

Results from the experiment

:

a) PTPv2 slave clocks vary significantly in their ability to synchronise to a grandmaster when first powered on

b)SV data puts some stress on an Ethernet switch, and this results in variation in transit times through the Ethernet and time delays of 60 to 63μs to travel from the source to the destination

A test bed to evaluate the performance of protection systems using SV was constructed. This test bed comprised of the following components: RTDS, PTPv2 clocks, Ethernet emulator, traffic generator and a precision Ethernet capture card.

"Understanding and Simulating the IEC 61850 Standard" by Yingyi Liang Roy and H. Campbell

Investigation onto the IEC 61850 modelling and simulation methods

Purpose was to explain the preliminary results of pilot projects and identify the coming milestones to facilitate widespread deployment of process bus

Tests were conducted using CVCOM 400["A smart modular merging unit platform"] and MICOM P442 with an Ethernet module. Based on the success further test were conducted at NGT (U.K.), Osbaldwick 400 kV GIB, RTE (France), Saumade 245 kV GIS s/s. Experiences from the experiments outline the huge potential advantages, including: cost and space savings, safety, reliability, availability, redundancy capability, and for sure: installation and exploitation easiness

In summary it is important for the Interoperability tests to be accurately defined, beyond the pure communication aspect. They shall also check the proper "operation" of the devices and particularly in the case of distributed functions.

"Digital Protection System Using

Optical Instrument Transformers and

Digital Relays Interconnected by an

IEC 61850-9-2 Digital Process Bus" by Prof. Mladen Kezunovic, Levi Portillo, George G. Karady, Professor

Sadik Kucuksari

January 2008

analysis protection system using measurements supplied by a merging unit

Review the IEC 61850, architecture, abstract services, data models, UML service model and simulation of substation automation system using J-Sim

Simulation of the

IEC 61850 protocol system based on J-Sim.

Outline in the documents is the lacks on SAS domain experts and the need for substation automation simulation tools to bridge the gap between programming (IT), networking and substation engineering skills.

"Test and Evaluation of Non-Conventional Instrument

Transformers and Sampled Value Process Bus on Powerlink’s

Transmission Network"by Pascal Schaub, John Haywood, David Ingram, Anthony Kenwrick and Anthony Kenwrick

March 2011

Provide a report on a pilot installation using NCITs communicating across a switched

Ethernet network using the Implementation Guideline for IEC 61850-9-2 (9-2 Light

Edition or 9-2LE)

compare the

compatibility and interoperability of products provided by different manufactures

All digital over-current protection operated well using measurements from a merging unit and interoperability:

The different manufacturers provided a CT’s

and IEDs that can work together; however, significant mismatch was discovered

between the current values measured by the IEDs

9-2 LE provides a guideline for the dataset, and conversion of measurements to digital counts. While this paper has covered most of the over current protection philosophies, more investigation onto the SV implementation on the various relays and the conformance to the implementation guideline still needs to be performed.

"Substation Automation based on IEC 61850 with new process-close Technologies" by Lars Andersson, Christoph Brunner and Fred Engler

Process bus overview and implementation of distributed function based protection system through the implementation of substation automation system process bus, specifically the merging unit

investigate market maturity of Process Bus equipment

The project had been running for a year smoothly at the time of the publication. Length errors were observed in the header part of the SV frame (before the APDU) and within the ASN.1 encoded data for some SV sources. These errors break compliance with

IEC 61850-9-2 and shows that protocol compliance testing is required before devices are deployed into the field.

The verification process for sampled values is suggested onto this paper as:

-The measurement dataset set consists of eight 32-bit signed integers (four currents and four voltages) and eight 32-bit status/quality words associated with each of the integer readings, which are based upon the dataset specified in IEC 60044-8. These and more are what we have been explored within this thesis and verified using wireshark as suggested in the this paper

"Performance Analysis of PTP Components for IEC 61850 Process Bus Applications" By: David M. E. Ingram, Senior Member, IEEE, Pascal Schaub, Duncan

Year: 2012

Protection system based on process bus implementation

Performance evaluation of commercially available PTP devices to meet the functional requirements of SAS system. PTP Time synch methods required and the effect of SV traffic on PTP performance.

None. Conclusion: The new process close technology and the new standard

IEC61850 offer several benefits for the design of a substation such as reduced wiring, reduced labour costs and the number of non-supervised functions will be reduced to almost zero, reducing the time until an error will be detected.

The benefits highlighted on the conclusion can realised only with a good understanding of the IEC 61850 standard, highlighting the need for substation automation and smart grids experts. Our project objective was to review the standard and build a good understanding on the standard to help us develop a simulation environment to help build skills within the substation automation domain.

"A Novel FPGA-Based Method to Design the Merging Unit Following IEC 61 850" By: Z.L. Yin, Student Member, IEEE, and W.S. Liu, Senior Member, IEEE

paper points out that the design of the

merging unit is the key element in implementing the interface based substation architecture

To provide a series

of tests that can be used by system designers to evaluate timing components in SV process bus

Results from testing PTP performance in the presence of

SV process bus traffic demonstrate the benefit of a "bottom up" component testing approach combined with "top down" system verification tests.

The results from the experiment show that the clocks selected for a substation timing system influence its performance of practically merging unit and should be one of the major consideration when moving from a simulation environment onto practical application

Test procedures for Sampled Values Publishers according to the "Implementation Guideline for Digital Interface to Instrument Transformers using IEC 61850-9-2" by Richard Schimmel

Explore the standard and give an overview of a merging unit and the data set contained within the sampled value message

Explorer Field Programmable Gate Array (FPGA) as a platform for the development of merging unit

Cost effective and simplified design methods to implement the main functions of the merging unit using FPGA were developed. High resolution, high reliability synchronizing signal distribution technique for the merging units from different

measuring points were developed

The suggested method has practical values for promoting fast emergence on merging units into industry but the author does not share enough on the actual implementation

"Traffic Generation of IEC 61850 Sampled Values" By: Jakub W. Konka_, Colin M. Arthury, Francisco J. Garciay and Robert C. Atkinson

Dept. of Electronic and Electrical Engineering University of Strathcly

Year: 2012

Simulate the generation of Sampled values using FD channels

Assist in simulation or emulation of IEC 61850-9-2 standard. Outlining the testing procedure for merging units based on the "Implementation Guideline for Digital Interface to instrument transformers using IEC 61850-9-2, version 2.1, July 2004" referred to as 9-2LE.

Generation and verification of sampled value using wireshark

a) DUT sends sampled value messages with the correct format of the ASDUs - 4 phase Currents, 4 phase Voltages and DUT sends sampled value messages. pCnt is incremented at each sample (ASDU).

b)A DUT sends sampled value messages with the following format of the link layer:

- destination MAC address = 01-0C-CD-04-xx-xx

- TPID = 0x8100

- VLAN priority as configured (default = 4)

- Ethertype = 0x88BA

- APPID = 0x4000

The expected result falls in line with the simulation of sensor node on a PC platform that we are implementing in our project which is outlined on the document. Generation of current and voltage signals and sends sampled value messages with 1 ASDU - noAsdu = 1, svID = xxxxMUnn01, smpCount = 0..3999 (50Hz), confRev = 1, smpSynch = False etc. Sampled values can only be verified using wireshark as the time synchronization cannot be met on a PC platform.