The Midwest ISO is installing an integrated control centre system (ICCS) to manage its regional network. The $50 million project is unprecedented in scope and presents major challenges for the ISO and its suppliers alike
As America’s electric industry embraces a more competitive, dynamic marketplace, and as the nation’s need for power continues to grow, the industry is on the cusp of seeing sweeping changes in how electricity is transmitted. Leading the industry in regional distribution is the Midwest Independent Transmission System Operator (Midwest ISO or MISO) in central Indiana.
The ISO’s $50 million transmission control centre, now under construction, may prove to be the worldwide model for management of electric transmission. The Integrated Control Centre System (ICCS) must accomplish an enormous task. It must work – continuously without interruption – when the Midwest ISO goes live on November 1, 2001. Market trials are scheduled to begin next June. The ICCS is designed to schedule electric transmissions in real time to a host of bilateral participants (sellers, buyers and marketers of electric energy). The MISO ICCS project is unprecedented in scope considering the size of the communications infrastructure, number of control areas, number of miles of transmission, amount of generation and load, and geographic area.
Figure 1. The ICCS is designed to schedule electric transmissions in real time to a host of bilateral participants
Integrating the Midwest ISO’s requirements for security, maintenance, training and settlement required vendors who could work within a tight deadline and provide a flexible, upgradeable system, according to Michael J. Gahagan, MISO’s Vice President and Chief Information Officer.
Because of the Midwest ISO’s complex needs, it awarded its control centre contract to an alliance of vendors known as the RTO Alliance. The primary contractor is Alstom ESCA Corporation of Bellevue, WA, which is responsible for the OASIS and ancillary services management, security monitoring and coordination, and the system infrastructure. Perot Systems Corporation of Minneapolis, MN, is responsible for program management, architecture, integration and RDBMS consulting. Open Access Technology International Inc. of Minneapolis, MN, will handle tagging, scheduling and checkout and congestion management. TenFold Corporation, of Houston, TX, is providing the billing and settlement system for wholesale customers who purchase power capacity, energy and transmission services.
The ICCS is not one mammoth system, but several systems that serve a complex network of industry sectors. The ICCS functional requirements were divided into four main areas: market interface, transmission market, transmission security, and settlement to serve both market participants and control areas.
One of the challenges with the MISO system was integrating all the functions of the system, while at the same time building a system that could be expanded as the Midwest ISO’s needs grow. A primary requirement was that the system has the ability to add functionality and be able to easily integrate third-party software. To bring all the components of the package together, Alstom ESCA designed a seamless integration infrastructure based on Microsoft’s distributed component object model (DCOM) and Corba (common object request broker architecture), the industry standard. DCOM supports remote objects via a protocol called object remote procedure call (ORPC). Corba and DCOM act as the central object bus over which system components interact with other system components located locally or remotely.
Various gateways are included to handle individual functions with other parts of the system. Software bridges will be used to interface between DCOM and Corba. Exchange of information between various subsystems is done through DCOM/Corba, through SQL calls, file transfers, and also through stored procedures.
Figure 2. One of the challenges with the MISO system was integrating all the functions of the system
The RTO Alliance also included a model building subsystem to maintain system, market and market participants’ data and to generate the appropriate databases and models required by various subsystems. The subsystem can build models from various data sources and validate the results. The integration infrastructure also includes an information storage and retrieval function that collects, time stamps and maintains all dynamic and static data for future review and analysis.
The importance of data archival and retrieval functionality cannot be understated. The USA is enjoying the longest post-war economic boom in history. That means that the demand for electricity to power its growing economic infrastructure has never been greater. From computers to manufacturing plants to subdivisions, the nation’s appetite for electricity has skyrocketed. Computers use 13 per cent of the nation’s power, up from less than one per cent in 1993, straining an aging, patchwork distribution system that works, but is in need of improvement.
As information flows from transmission owners, generation control areas, transmission customers, security coordinators, external control areas or regional reliability councils, it has to pass through the ICCS and back to the control areas in real time. And that data can include many critical items: transaction schedules, load forecasts, North American Electric Reliability Council (NERC) reports, and maintenance status reports. On the output side, the system must confirm transaction schedules and requests, state estimator results, reserve allocations, voltage schedules, transmission loading relief actions and maintenance schedules.
To maintain a high level of consistent reliability for the regional grid, control area operators and security coordinators must receive timely and complete operating information and have the ability to use it in the analysis of system conditions. That includes knowing their own operating reserves and the amount of reserves available in adjoining areas. Only an independent transmission operator can objectively evaluate conditions on the grid and respond accordingly.
The ICCS system architecture is based on a three-tier client server model. The client side user interface is web based, with the middle tier responsible for servicing the web requests and coordinating the application and database requests. The server tier is responsible for servicing the database requests and application processing. The adoption of the three-tier client server approach allows the ICCS system to be both scalable and highly available.
The ICCS is built upon industrial strength hardware with field proven technology. Compaq GS-80 and ES-40 Alpha Tru64 UNIX servers form the core database and application servers with Compaq NT servers supplying the support functionality. Oracle technology was selected to meet the RDBMS functionality and availability requirements for the ICCS system.
The ICCS system servers are quad redundant. Each server has a dedicated local secondary standby server. In addition there is a similar dedicated server pair at the backup site. This distributed level of redundancy will allow the ICCS system to achieve the 99.95 per cent system availability requirement.
Energy service providers, load-serving entities, power marketers, power exchanges, and generation and distribution companies will interface with the system using standard web browsers. The market interface subsystem ties Oasis and transaction management functions together and adds additional capabilities to provide the required interfaces for ancillary service schedules, customer registration, interfaces with reliability councils and the publication of general market data. The market interface subsystem also provides the capability to accommodate programming interfaces. Data requests that are received from market participants are validated and then passed on to the appropriate entity. The market interface subsystem acts as a two-way street. It also has the capability to provide data back to market participants and to the general public.
The cornerstone of the market interface subsystem is the combination of web and distributed server and RDBMS technology allowing multiple servers to work together to service market participants’ requests in a timely manner.
Transmission market system
The transmission market subsystem handles congestion management, tagging scheduling and checkout, generation and transmission maintenance, ancillary service management, available transfer capability (ATC) calculation, power flow sensitivity factors and real-time balance and reserve sharing. The congestion management function is complex. The complexity is due to the size of the MISO system, the number of entities combined with the number of constrained interfaces. The congestion management function will be used to alleviate congestion on the system and includes generation re-dispatch, transmission resale, load shedding, network reconfiguration, maintenance rescheduling and operates in conjunction with NERC transmission loading relief protocols.
Open Access Technology International (OATI), one of the industry leaders in providing transaction management systems, will provide the MISO with tagging services, scheduling system, congestion management toolsets, and planning model building applications. The tagging scheduling and checkout subsystem processes energy tags and submits schedules. It is comprised of interchange scheduling, loss calculation, NERC tagging and schedule approval, post interchange confirmation, and interchange transaction curtailment.
The ancillary service management subsystem analyses the system requirements for the following six ancillary services: scheduling, system control and dispatch service; reactive power/voltage control service; regulation and frequency response service; energy imbalance service; operating reserve – spinning reserve service; and operating reserve – supplemental reserve. The MISO is not responsible for providing ancillary services. It is the transmission customer’s responsibility to procure the necessary ancillary services. Under the FERC order 2000 ruling, the MISO is the ancillary service provider of last resort.
Figure 3. MISO’s $50 million control center will go live in November 2001 after a series of market trials
The ATC function uses the committed transmission schedules to calculate the remaining transmission capacity, which can then be used by other functions requiring the data. The power system analysis subsystem calculates power transfer, generation shift, outage, and outage transfer distribution factors. The establishment of a MISO real time balance system has not yet been identified. Consideration is being given for the establishment of a future reserve sharing system within the MISO region. It is hoped that one or more power exchanges will be formed in the Midwest supporting markets covering real time balance, ancillary service and related activities.
Perot Systems will utilize their expertise in program management, providing a seamless and integrated solution to MISO.
Transmission security system
The transmission security subsystem provides real-time and study network analysis functions, as well as all supporting functions for the energy management systems. Real time data including line flows, bus voltages, logical device status, load, generation, and shunt data is collected in real time from the MISO control areas across the MISO wide area network utilizing the ICCP standard. The real time data drives the ICCS Scada subsystem and supplies measurement data for the real time power system analysis functions. The real time network analysis functions include model initialization, parameter adaptation, state estimation, contingency analysis, optimal power flow, voltage scheduling, and voltage stability.
The transmission security subsystem also forecasts the load by collecting load forecast information from individual generation control areas and then calculating the load forecast for the MISO transmission control area(s) where information is not available.
The MISO is building a large model containing real time and planning models covering the entire MISO region to be used by the ICCS system. The final model is anticipated to be approximately 25 000 buses.
Planning tools are provided to allow MISO to perform transmission planning for the MISO region. The ICCS planning tools include planning power flow, contingency analysis, fault analysis, ATC calculation, and voltage stability.
Settlements and billing
MISO will use SettlementNow!, provided by TenFold, to automate the complete billing cycle for transmission service billing. MISO will be able to generate customized invoices based on specific customer preferences.
The settlements and billing subsystem comprises several major processes. The energy balance process is responsible for energy data correction support, energy imbalance calculation and monitoring and inadvertent energy calculation and monitoring.
The service compliance service performs major monitoring activities, including ancillary service monitoring, scheduled generation monitoring, schedule transaction monitoring and MISO directive compliance monitoring.
The settlement process includes: distribution of revenue; application of rates and charges; and the management of grandfathered agreements.
The accounts and billing service performs the following major activities:
- Accounting for all MISO transmission and non-transmission related services for each calendar month billing cycle
- Constructing and generating of all bills for all MISO participants
- Collection and distribution of all MISO revenues.
The distribute resolutions process includes two major activities: processing all disputes received by the MISO according to the MISO Tariff and/or MISO Agreement; and implementing the resolution of disputes as applicable.
Lastly, the reporting and auditing service performs budgeting of revenues and expenses, FERC reporting requirements, external reporting, energy balance reports, and auditing support.
“Deregulation is accelerating change in our industry and is making our contracts more complex,” said Gahagan. “SettlementNow! will give us the ability to manage intricate contracts and the flexibility to respond to changing customer requirements without reprogramming.”
With SettlementNow!, MISO will be able to define business rules to control sources of data, the complex calculations of each customer’s bill, and the presentation of billing data to each customer.
“Our involvement with MISO demonstrates TenFold’s ability to deliver dynamic applications products that rapidly adapt to new and changing markets,” said Don Jefferis, president of TenFold Energy, “We’re pleased to be the best-of-breed selection for a leading regional transmission operator like MISO who is pioneering a new model for energy transmission in the Midwest.”