Applied Mechanics and Materials Vols. 291-294 (2013) pp 1308-1311 Online available since 2013/Feb/13 at www.scientific.net © (2013) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMM.291-294.1308
Software Solution Implementation for Regional Balancing Mechanism of Electrical Energy Costin Cepisca Nikolaos Bardis
Marian Morcovescu George Seritan Sorin Dan Grigorescu Cosmin Banica
University POLITEHNICA, Bucharest, Romania
[email protected] [email protected]
[email protected] [email protected]
[email protected] [email protected]
Keywords: Power Network, Day-ahead Balancing Mechanism, Software for System Analysis
Abstract. The aim of this paper is to present how the Regional Balancing Mechanism (RBM) can be facilitated by a specially developed software solution. RBM ensures up-ward regulation in power deficient area and down-ward regulation in power surplus area at Regional Market for Balancing Energy (RMBE) prices. The RBM proposed solution for both the day–ahead and intraday transactions determines the transaction volumes and payments resulting from the selected offers Introduction Set up of national day – ahead balancing mechanisms looks essential for the security of electricity supply in each country. National Balancing Mechanism (BM) is unavoidable market instrument for the Transmission System Operators (TSO) dispatching service for solving the power imbalances and network constrains in his control area. During the operating (delivery) day, the TSO balances the market and dispatches generation according to dispatch schedule. Intra – day deliveries on the BM is primarily meant to resolve the balancing needs of Balance Responsible Parties (BRP) that are unable to meet their obligations. The same phases can also be imagined for a regional context, where the schedules address cross – border power exchanges, with the decisive advantage [1]. One of the main targets of the liberalization of the electricity sector in the European Union is creating an Internal Electricity Market (IEM) by introducing competition in generation and supply, not only within national markets, but also on an international scale. The Directive 2009/72/EC [2], sets the legal framework for developing a competitive, secure and environmentally sustainable electricity market by establishing common rules for generation, transmission, distribution and electricity supply. The SEETSOC European FP7 Project addresses the needs of South-East European TSOs in harmonization and integration of the region with the rest of the European power network. One of objectives of the project is the design, development and testing of the regional balancing mechanism module (RBM) and his integration with all modules in the SEETSOC platform [1]. RMBE is of interest, particularly, for releasing cross – border constraints (power flows kept at or below limits) and for the control areas with permanent/temporary weak balancing resources. Resolving deviations from Cross Border (CB) exchange schedule by seeking bids and offers via the RBM to reduce or increase generated output as appropriate would raise the question of additional capacity payment; this could be achieved by acquisition of ancillary System Services (SS) on the centralized national (regional) market prior to offering on the RMBE. RBM software solution The SEETSOC RBM program is a set of software modules which implements the regional balance mechanisms used by market operators as the backbone of the energy market transactions. The RBM software solution for both the Day-Ahead and Intraday RMBE functions of the business process is described in the SEETSOC deliverable D5.1.2 – Software Implementation [1].
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The RBM for both the day–ahead and intraday transactions determines the transaction volumes and payments resulting from the selected offers in a three – step procedure, namely: • Placing of offers for each balancing interval and each balance energy type followed by their formal acceptance / rejection. • Offer selection. A fixed and firm schedule bidding for the balance energy is carried out that ensures transaction selection and pricing, i.e. the establishment of regional market for balance energy clearing prices. • Notification and transaction settlement. The schedule is executed during the dispatching day (D). For each balancing interval, the imbalance quantity – price pair is established based on the final dispatch order for the BE purchase. In order to support this three-step procedure, the RBM has to perform an additional set of tasks, such as: • Managing the users who are placing bids and performing transactions • Allowing operators to monitor the transactions and record any difference between scheduled and delivered quantities • Generating reports of the performed transactions for the use of the operators RBM software implementation a) For TSOs The representatives of each TSO can submit bids to be considered for transactions, usually from the web interface accessible to them. The bids are encoded in a standard XML format so they can be generated by any in-house tools compliant with the standard with only trivial modifications – but a reference implementation of such a graphical tool, which can also submit the offers by connecting directly to the server, is also provided [3], [4]. Once the bids are accepted, they enter in the selection process and representatives are notified if they were accepted for scheduling, as well as of any necessary change of delivery parameters. Representatives can also track the status of their bids in real-time, and have access to all the bids they have submitted through a basic web interface – Fig. 1.
Figure 1. User interface: viewing the bid history.
b) For operators Market operators can perform offer selection and scheduling from a dedicated interface, and can keep the delivery statuses up-to-date using a basic web interface. As scheduled transactions are performed, they can generate the required payment information. Operators can also perform user management functions as well as various maintenance operations which are required for the smooth functioning of the RBM system –Fig.2.
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Figure 2. Operator interface: merit order information. The server-side software modules are implemented in the Python programming language, using web2py – a well-established, enterprise-class, Open Source framework, distributed under a highly permissive license – to integrate the back-end business logic with the user interface. The choice of Python and web2py makes the RBM program effectively platform-agnostic: it can run on any operating system that can run Python and a web server (including Windows, Linux and Mac OS X), and can use any widely-available database management system – including the popular MySQL and PostgreSQL, but also highly scalable systems such as MongoDB. Some of its functions, which are required for integration with desktop clients, are also available through web services implemented using the standard SOAP protocol. These two traits result in a great deal of deployment flexibility. Platforms can even be switched seamlessly – it is possible to move from one hosting system to another, changing everything, from the web server to the database management system used, and the system will continue to run without any data loss. Secure access can be granted using the HTTPS protocol, which is supported by any modern web browser and operating systems, and results in a well-encrypted, secure communication that ensures the security of transaction-related data. The reference desktop client is implemented in C++, using the cross-platform application framework Qt – an Open Source application framework for desktop applications that runs on all operating systems and even on mobile platforms. However, the platform is not tied to its use – as the encoding of the bids is an open standard, any client that complies with it can be used. Test results for the system Offers have been uploaded, and system tests were performed to ensure the proper functionality of the whole modules assembly. For downward tertiary regulation data was loaded in XML format files and the program filters data in conformity with the specifications; the results are presented in Fig.3. Sell and buy issues were treated separately, and the accepted offers are specified. Conclusions The RBM system has a modular design using standard interfaces and XML-formatted messaging, web-based interfaces and web services for the system users. It could also be a stand-alone program which can be installed anywhere in a TSO’s operational network and integrated into the existing Market Management Systems (MMS) which are used in the TSO run centralized electric markets. As it is developed in cooperation with several TSOs from SEE, it considers their requirements, as well. In addition, it may be further upgraded with additional functionalities.
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MCP=31.57Euro/MW
Figure 3.
Software results for Clearing Price - Downward Tertiary Regulation
Acknowledgements This work was financially supported by the Project no.TREN/FP7EN/239453 and the Project no.75EU/2010 Romanian Research Authority. The authors would like to acknowledge the contribution of all partners of the SEETSOC consortium for their contributions to the realization of the project. References [1] Information on http://seetsoc.ntua.gr [2] Directive 2009/72/EC of the European Parliament and of the Council of 13 July 2009 concerning common rules for the internal market in electricity [3] C. Cepisca, A. Lazar, S. D. Grigorescu and G. Seritan: WSEAS Intl. Conference Recent Researches in System Science, Corfu (2011) p.394 [4] X.P.Zhang, Analysis of Electricity Markets with Equilibrium Models (IEEE Press, 2010)
Advances in Energy Science and Technology 10.4028/www.scientific.net/AMM.291-294
Software Solution Implementation for Regional Balancing Mechanism of Electrical Energy 10.4028/www.scientific.net/AMM.291-294.1308
