An Introduction to ADMS

The Operation, Command and Control of Electricity Distribution Networks

Derek Macfarlane

• Publisher: Austin Macauley Publishers
• Year: 2021
• ISBN:
  9781398406025
• Topic: Pedagogía
• Subtopic: Tecnología educativa

Advanced Distribution Management Systems are one of the first mature successful products from the information age. Over a 30-year period, a series of computer applications, all related to the real-time control of electricity distribution networks, were developed to meet the challenges of privatisation, deregulation and CO2 reduction. These have evolved into ADMS, which now plays a major role in adapting traditional electricity distribution networks to meet the challenges presented by the transition to renewable generation and reducing our carbon footprint. The purpose of ADMS is explained and component functions of ADMS are described. The ADMS relationship with other corporate IT investments is also discussed. Furthermore, the maintenance needs of ADMS are described and direction is given on how to extract maximum value from an ADMS investment.

1
Introduction

This book is intended to be read by the electricity industry staff who are looking for IT systems to improve their electricity distribution processes and network performance.

I was once challenged by a utility manager, who had as their aim to be the best distribution business in their region. “How can you make us the best if you only sell us the same software you sell everyone else?”

My answer used a domestic analogy. “Consider a street lined with houses and front gardens. All the householders have similar garden tools, yet some gardens are much nicer than others. The differences are twofold: first, you must have a clear understanding of what tools to buy and what conditions to create to enable you to compete with the best, and secondly, it is in the skill and knowledge you apply to get the best out of your tools that makes the difference. These newly required IT skills are the modern differentiators between electricity utilities. Those who understand their IT investments, how to maintain them, how to get the best out of them and how to keep the data up to date and accurate, these are the utilities with benchmark levels of performance for their type of network.”

I helped to sell ADMS to electricity companies around the world for 16 years, and from my experience many companies become confused in what they want, they may be influenced by previous investment decisions which slant their assessment of what they need for an ADMS. They are obliged to make decisions between technologies without having the prior experience of different outcomes from different solutions. Over these years, I have been involved in wins and losses of contracts and, the joys of winning apart, the most informative moments were in discovering why we lost. Sometimes, we lost for what we perceived to be good justifiable reasons and in others we were prepared to bet we would be getting a second bite at that opportunity a few more years down the track and happily we converted several of those at the second time of asking.

I have tried to prevent this book from becoming a plug for one solution. It discusses several options at various junctures through the topics and hopefully explains the differences between some of the key technology decisions, dispel some of the myths and seek practical workable solutions. I look at various options and attempt to explain my way through the technical quagmire towards the solution that is best fit for each customer.

Then, having spent millions to buy an ADMS, many utilities do not use it to its full advantage. To use another analogy, having bought a fancy sports car they only drive it in third gear. In this book, I hope to enable the power engineers with a better understanding of the IT industry, the relevant IT applications and how to get the best out of their investments.

In writing a book, I am in effect taking a photograph of a dynamic and fluid process. This process is continually developing and ADMS is continuing to develop as the challenges, ideas and operational experience also evolve. However, the book is needed as a baseline of what we currently can do and where we want to go.

2
The Purpose of DMS
and ADMS

2.1 A Cautionary Note

The IT vendors each use the acronyms DMS and ADMS, Distribution Management System and Advanced DMS, for their own purposes, there is no standard definition of what is an ADMS or a DMS, so most vendors claim they have one. Potential customer utilities need to have an enquiring attitude and a firm concept of their business needs prior to selection of their chosen vendor/product. IT systems are expensive to buy and complicated to maintain. The only way of ensuring value for money is to pursue a strict business benefit case for each function. The IT industry is an ideas factory, and many ideas look good on the screen, but some of these are just technical nice to haves if they do not have a primary justification in a costed business case.

Volvo has an advertisement for the XC40 with the tagline, ‘Everything you need, nothing you don’t’, and this implies that IT for cars is in a similar position to ADMS in that technology can now offer a lot, and the blind rush into the newest available is now needing to be replaced with rigorous process, users and needs analyses. New IT features may distract Volvo drivers from their prime task which is driving safely, similarly new functions in ADMS can distract or divert the control engineer into interesting and diverting insights but lose track of the main function of controlling the network and operating safely.

What is the business process being modelled?

How many distinct types of user are involved in the process?

Which users need which features?

What would happen if the feature was not available?

2.2 Definitions of DMS and ADMS

An initial definition for DMS, it is the IT system which is used for operation and control of the electricity distribution networks, that is networks operating at high voltage (HV, 132kV down to 20kV), medium voltage (MV, 20kV down to 1kV) and low voltage (LV, below 1,000volts), ending on customers premises with a terminal protection device and a meter. This includes interfaces passing real time information between DMS other business processes affected by real time operations. Typical users of this system and its data are:

Control engineers, outage planners, outage dispatchers, operating crews, customer call takers, SCADA maintenance staff, data maintenance staff, diagram maintenance staff, reports users, general management, regulatory management, customer management, asset management, major incident management and IT management.

An initial definition of ADMS: it productises DMS within the full asset management lifecycle and adds the productised interactions with Asset Management Systems, Geospatial Information Systems, and other corporate IT systems to ensure consistency of data between systems and seamless interaction from ‘back office’ (design, asset strategy and management) and ‘front office’ (live network operations in DMS).

Typical users of ADMS include most of the DMS users, plus GIS data maintenance staff, asset managers, GIS based network designers and planners.

Figure 1: DMS within the ADMS Larger Picture of a Distribution Company

DMS is all about operating the assets connected to the live distribution network:

• Responding to requests from project engineers to connect new assets to the network.
• Responding to requests from maintenance engineers to isolate items of plant for maintenance.
• Responding to unplanned events affecting the network, such as storm damage, network-initiated alarms and events.
• Interacting with transmission control.
• Ensuring the distribution network is operated safely and kept stable.
• Ensuring crews who operate switches or work on the network, do so with safety as the prime focus.
• Ensuring the public is kept safe from the potential dangers from electricity networks.
• Providing customers with the most reliable supply practicable.
• Providing customers with the quality and amounts of power on demand, within pre-agreed limits and within the standards.

The DMS, therefore, is a collection of functions essential to supporting control engineers in the safe management of the network, the reliable delivery of electricity to customers and the safe deployment of crews who are switching or working on the network.

3
DMS Functions and
Their Purpose

Figure 2: Development of DMS Functions from 1991 to 2016

Figure 2 shows a block diagram of typical DMS functions available today. The immediate understanding of this diagram requires an acronym dictionary, and the descriptions follow in the next section. However, each ADMS vendor would produce their own block diagram and it will hold clues as to how each vendor’s system is put together. For instance, it may show OMS and or SCADA as an interfaced product rather than being embedded in DMS and this tends to imply that their OMS or SCADA has been developed separately, it may not be their own product, possibly a commercial arrangement with a third-party specialist function provider, or indeed these products might have been purchased and brought into the common stable of functions provided by the vendor. In essence, they are separate products with their own unique software but have been custom interfaced into the vendor’s stable product. Some vendors have all or most of these components within the one software version, as licenced modules within a single DMS software suite developed as an integrated system.

3.1 DMS

The major real time business processes that needed to be modelled in DMS are:

• The management of safety as crews operate switches on the network and as crews are set to work.
• Managing the network model as used in the control room in a manner that always reflects the actual state of the real network.
• Managing the unplanned outages and organising the response, investigation and recovery.
• Managing the operational work including requests for outages for new connections or for maintenance.
• Managing the loading of every component of the network as it attempts to meet the demand of customers.

These processes are not mutually exclusive, there are situations where they interact, for instance, SCADA remotely operating a switch requires to also be controlled and recorded as part of switching management, but its data acquisition role feeds into the load management process. SCADA sensing a fault and tripping a circuit breaker requires to be recorded in both the switching management process and the unplanned outage management process. The planning of switching outages requires to check the prospective loading of the adjacent circuits affected by the temporary abnormal feeding arrangement and, therefore, involves elements of the load management process.

Figure 3: The interrelationships between the major operational
processes and the ADMS functions

3.2 NMS

NMS is the Network Management System. This has four major parts:

• Modelling the network.
• Updating that model in real time.
• The management of planned and unplanned switching on the network.
• The management of safety documentation.

There are several network models that can be used, a geospatially accurate model found in the GIS, a schematic network model, (the electrical equivalent of the London underground map,) and a geo-schematic which accepts some geospatial inputs to assist in orientation within a schematic model. For operations purposes, the schematic provides the clearest representation of electrical connectivity and the current state of switches and other network components. The schematic is, therefore, used for HV and MV networks, the LV network, due to its massive size is usually a geo-schematic based on the GIS geospatial record of the LV assets. There is no other reason other than clarity of connectivity, to use a schematic at HV and MV and indeed most US utilities do use a geospatial or geo-schematic model for their MV network, because the polar orientations are often used by crews to identify where they are operating.

The lower the voltage the higher the involvement of crews on site in switching and working on the networks. EHV transmission networks are important, but relatively small and work tends to be done on the basis of large contracts with only a final test and connection to the live system. The volume of these changes tends to be single figures, under ten major additions/changes per year. This relatively low level of disturbance meant that the EHV control systems (EMS) tended to ignore model change as a regular process and allowed one off changes to be inserted in a relatively manual bespoke process. The HV network is larger and the MV network is ten to one hundred times larger than EHV and the corresponding amount of work on the network also increases. This produces a workload of thousands of network additions and changes per year, and, therefore, NMS requires a business process to manage the introduction of changes to the model. A major requirement of this business process is that it keeps the model accurate in real time so that the control engineer and the site personnel both understand the current connectivity of the network. Changes to the schematic operational control diagram must be implemented in real time and within a business process that provides those responsible for safety, the control engineers, with a means of prechecking and approval prior to implementation. NMS includes this process within its functions.

Switching management is the major activity going on in a distribution control centre. This can take several forms:

• Manually initiated, remotely controlled automated switching by the control engineer.
• Manual switching, planned in advance, under direct command from control engineer to an onsite operative, who may be an engineer a linesman or other operationally qualified tradesman.
• Manual switching as an unplanned response to an unexpected network event.
• Intelligent automation driven switching triggered by an unexpected network event.
• Manual and or automatic network adjustment in response to dynamic network conditions such as voltage levels or loading constraints.

NMS should manage all five forms in one consistent set of switching logs. Each switching log identifies what type of job is ongoing and has a unique identifier number. The switching log requires to identify the substation name, the switch name, the type of operation undertaken, the operator’s ID, the control engineer’s ID and the relevant timings of each instruction. The timings include time of instruction, and time confirmed complete.

Switching logs for EMS EHV controls tend to be one log per control engineer, however, to manage the massive amount of switching done at HV and MV in distribution control rooms NMS usually provides a filing system of switching schedules, and each control engineer manages around 20 or so switching schedules per shift. Switching schedules can be created and checked in advance for known events such as an outage for maintenance of existing network components or for the addition of new network components such as a new substation supplying a new factory or housing estate. Control engineers can also keep available a switching log for dynamic switching in response to network constraints similar to the EHV switching log, and also the distribution control engineer can create a new switching log on the fly as faults occur and they wish to capture all the relevant switchi...

Table of contents

• An Introduction to ADMS
• About the Author
• Dedication
• Copyright Information ©
• 1 Introduction
• 2 The Purpose of DMS and ADMS
• 3 DMS Functions and Their Purpose
• 4 Data Storage in ADMS
• 5 The Interaction of DMS with Other Corporate IT Systems
• 6 Maintenance of DMS
• 7 Non Functional Requirements of DMS
• 8 Extracting Added Value from ADMS
• 9 ADMS Yesterday, Today and Tomorrow