SECI Regional Transmission Planning Study

Transcription

1 SECI Regional Transmission Planning Study T. Cerepnalkovski* P. Miller D. Bajs G. Majstrovic S. Mijailovic M. Vukovic N. Rusanov N.Gamov ESM CMS Energy Energy Institute Hrvoje Pozar Electricity Coordinating Center (EKC) EPB&H NEK Republic of Macedonia USA Croatia Yugoslavia BiH Bulgaria *Phone: , Fax: , trajce@esmak.com.mk ABSTRACT: This paper presents the activities performed in the framework of the SECI Regional Transmission Project sponsored by the USAID that was started in March The regional model has been built for the year 2005 and studies are being performed for regional evaluation of potential interconnection investments. This paper describes the work and some results of the study. Keywords: Interconnection, Investment, Power Flow, Regional Planning, Electricity Market. I INTRODUCTION The SECI (South East Europe Cooperative Initiative) Project Group on Development of Interconnection of Electric power Systems of SECI Countries for Better Integration to European System during the preparation phase identified proposal for five projects for further development as common priority for the region: I. Rehabilitation of the existing transmission lines and substations in Bosnia and Herzegovina and Croatia in order to reconnect the south wing of UCPTE II. Feasibility and Technical Study for east-west corridor in the high voltage transmission systems of the southeast European countries, including issues related to the interconnection of the region to the Turkish power grid.. III. Investigation of economic and technical advantages of the integrated operation of the interconnected Balkan Electric Power Systems IV. Tele-information system for the connection of the dispatching centres of the power systems in the region in order to improve the cooperation, electricity exchange and opening of the electricity market V. Study to define a revitalization methodology for high-voltage lines and transformer substations by identifying a priority criteria As a follow up, few projects were initiated and the Regional Transmission System Planning (TSP) Project, as well, with main sponsorship of USAID, Energy and Infrastructure Bureau for Europe and Eurasia. The other aspect for initiation of TSP project was the necessity for better regional evaluation of the possible investments in new power interconnections. The formal Organizational Meeting was held in Skopje on March 6 th and 7 th, The MoU and the Work Plan were reviewed and adopted. In this Project the following countries/companies are involved: Albania KESH; Bosnia and Herzegovina ZEKC, EPBiH, EPRS, EPHZHB; Bulgaria NEK; Croatia HEP; Macedonia ESM; Greece PPC/HSTO; Hungary MVM; Romania Transelectrica; Turkey TEAS; Yugoslavia, Serbia EPS, Montenegro, EPCG. The countries of Southeast Europe have committed to improve their electricity systems and create a regional electricity market integrated with Western Europe by One important element of a fully functional regional electricity market is the ability to perform electric transmission planning on a regional basis in order that projects not only benefit each national interest, but also the region as a whole. For the utilities from the SECI countries, which are undergoing different degrees of structural and functional change in a political environment, developing a regional transmission planning organization with the necessary tools and procedures suitable for the changing market is an urgent need. In many parts of the region the electric power sector is undergoing restructuring, unbundling and privatization while others remain vertically integrated. The opening of the electric market and the changing regulatory frameworks throughout the SECI region will allow competition, introduce the new role of independent power producers and require open transmission access to all producers. In addition, the growing interest in Southeast Europe for a common electricity market will provide opportunities for utilities from SECI countries to import and export power to meet national objectives while optimizing regional transmission and generation utilization. Finally, the goal for many of the SECI countries to enter the European Union requires that each utility, as well as the region, have fully functional

2 transmission planning capability and the flexibility to meet existing and future EU and UCTE requirements. This SECI Electricity Interconnection Project Group initiative will help to improve and sharpen the capabilities of SECI member utilities in optimal power flow and investment planning methods for determining economically viable investments that improve the transmission systems and take advantage of opportunities for mutually beneficial trade. The overall objective of this project is to promote regional cooperation in transmission planning through the development of common transmission planning tools and methodologies. Common transmission planning capabilities have proven to be the technical catalyst for improved regional electric planning communications, better understanding of least cost solutions and the basis for bankable project proposals in other parts of the world. This involves the installation of the well-known PSS/E transmission planning software in each country (where it does not exist) and the training of selected transmission planning personnel in Steady State Analysis, Optimum Power Flow and Dynamic Simulation. The project team will work with utilities in the region to convert and improve existing planning data, will assist in developing regional analyses utilizing the planning software to identify key transmission bottlenecks and incorporating the results from on-going and future feasibility studies of specific transmission interconnection, rehabilitation and upgrade projects. In this paper further the excellent work of all participants in the project from the SEE region and particularly the members of the ISTG (Interconnection Study Task Group) on preparation the regional models and performing the regional studies calculation and outcomes and results are briefly present and described. II BACKGROUND A Power Systems status and interconnections Power Systems of the SEE (South East Europe) countries have a different status concerning the UCTE membership: some of them are members of the UCTE (Slovenia, Croatia, B&H, FR Yugoslavia, R. of Macedonia and Greece); Bulgaria and Romania are in advanced process for full UCTE membership and Turkey has made the application and started the procedure. Hungary, through CENTREL, has become a member of UCTE. On the other side, as a result of the war activities in ex- Yugoslavia, very important points in the high voltage network in the region were damaged and have been out of operation for many years. They are: Mostar (B&H) Substation 400 kv with connected lines that caused the interruption of the Adriatic line; and Ernestinovo (Cro) Substation 400 kv with connected lines that caused interruption of the North ex-yugoslavian power corridor. As a result, the southeast UCTE wing was separated from the main European interconnected grid. In the mean time, UCTE members from the southeast island (Greece, Macedonia, Serbia, Monte Negro and part of B&H) were interconnected and work in parallel synchronous operation mode with Bulgaria, Romania and Albania. At the moment there is only one Turkish interconnection line with the region and it is being used for exchange of power, in an island mode operation only. The second interconnection line 400 kv between Bulgaria and Turkey is under construction and a new 400 kv interconnection line between Greece and Turkey is under study. B Related initiatives in the region The European Commission (EC) project Balkan Energy Interconnection Task Force was established in 1997, and is one of the background documents for the SECI Project Group activities. In the framework of this Task Force, the Inventory of the potential interconnections in the Balkan region was described. The Study for Regional Electricity Market (REM) was initiated in 1999, under the EC sponsorship. Based on this Study, two Memorandums were signed by Energy Ministers in the region for REM development. The Stability Pact Program for the SEE region was established, and lot of power infrastructure studies and potential investments were identified and funds pledged. The SECI Project Group has in mind all of these activities and the necessity for cooperation to avoid duplication of efforts. III SEE REGIONAL TRANSMISSION MODEL CONSTRUCTION One of the project objective was to construct the regional transmission model. The regional model was built using the PTI PSS/E software. In the framework of the project this software was purchased and delivered and appropriate training courses for the experts from the power companies in SEE were performed. That means that transmission planning engineers in SEE have the universal software tool and have easiest way for exchange the information and data. Regional model was planed to be used for: - SEE regional planning studies - Studies and investigation performing by the participating countries in SEE The regional model was built based on the internal, models prepared by the experts in the countries (power companies/institutes). The EKC (Electricity Coordination Center from Belgrade) was obliged to joint all individual models, performing the harmonization, tests of accuracy, implementing the links (interconnections) for the base case. Interactive communication and work in the process of the model construction was established and several steps were performed until the final product was outcome. In addition, based on the established cooperation with relevant UCTE

3 bodies, UCTE equivalent on the borders of the region was defined and implemented. This is very important, having in mind the influence of the power flows across the region and neighboring power systems, particularly Northern part of Italy and Austria. Complete work on the model construction was directed and reported to Project s Technical Groups that consist of the experts from all participating companies (countries) and the consulting company (CMS) as manager of the project. The regional models were constructed based on the following assumptions defined by the Projects Technical Coordinating Group (TCG): - Target year is In the base scenario 2 nd synchronous zone will be reconnected to the main UCTE network. That means that S/S Mostar and S/S Ernestinovo will be reconstructed and in operation before Power systems of Bulgaria and Romania will enter in UCTE before kv and 220 kv network will be implemented mainly, and lower level were has significant influence Winter and er peak condition will be analyzed and utilities will define the power balance and implement it in the internal models (Table 1.) - The existing and the new interconnections confirmed to in operation until 2005, approved by TCG (marked as In in Table 4), will be implemented in base scenarios - The model will be prepared for the steady state analyses for this first phase of the project - The base case models will be constructed for internal balanced systems - The two base sub scenarios will be considered: with and without power system of Turkey in synchronous operation with UCTE - The new power line Turkey Greece will be in operation =2005 or >2005 Table 1. Available power balance data EPS Total (GWh) Year 2000 Year 2005 Total (GWh) Alb BH Bul Cro Mkd Rom Tur Serb MN Table 2 presents the structure of the models and number of different elements per country implemented in the regional models. It is interesting that the companies for their internal use upgrade the regional models with detailed internal system representation. It is one of the important benefit of this work. Table 2. Model structure Alb Bul B&H Ita Cro Hun Gre Tur Mkd Rom Slo Yug Aus Node PP Gen Load OHL Tran One of the assumptions was to consider balanced internal systems as base cases. But, few power systems showed up unbalanced in their internal models, because of different reasons (long term contracts Turkey with Bulgaria, Hungary with Slovakia and Croatia with Slovenia), as shown on Table 3. Table 3. Deficit in Power Systems (Including contracts) MW Winter er Albania Greece Turkey Croatia Hungary Apart from the defined long-term contracts, some adjustments were agreed with lower influence on the assumptions. IV SEE REGIONAL INTERCONNECTION STUDIES The models were used for preparation the technical studies to investigate the regional impact of the new interconnection investments considered by the different power companies in SEE. The Interconnection Study Task Group (ISTG) was established to perform the studies, consists of the experts from: Energy Institute Hrvoje Pozar, Zagreb, EKC, Belgrade, NEK, Sofia, ZEKC, Sarajevo and managed by CMS, USA and under coordination of ESM, Skopje. The studies are based on the steady state and security analyses for the defined time horizon of the year A list of interconnection investment projects for studies consideration was discussed on the TCG meetings. Agreed list is presented in Table 4. and shown in Figure 1. In this Table the projects that are considered to be in operation before 2005 are marked as In, while other candidates are marked as Options. Technical and Working Groups have defined characteristic different scenarios in order to consider possible bulk power transfers across the region. Exchange scenarios are given in Table 5. Based on that four models were developed and distributed to all participating companies for there further usage: Winter peak with Turkey, Winter peak without Turkey, er peak with Turkey and er peak without Turkey.

4 Becescaba Rosiori Heviz Sandorfalva Oradea Divaca Cirkovce Krsko Pecs Tumbri Zerjavinec Sombor Subotica Arad Ernestinovo M eline S.M itrovica B. Luka Ugljevik Djerdap Portile de Fier Tintareni Isaccea Konjsko Mostar Kozloduj Nis T rebinje Ribarevine Sofia West Varna SECI kv Interconnections Existing New In New Option Podgorica Kosovo B C. M ogila Skopje 5 Blagoevgrad Stip Dubrovo Tirana B itola Phillipi Elbasan T hessaloniki Florina Kardia M aritza 3 Babaeski Hamidabat D C Link to Italy Arachthos The calculations were done by ISTG members using the PTI PSS/E software. As we considered 13 scenarios of exchange and 12 new candidate investment options, several hundreds of power flow calculations have been performed. All results are included in the final report together with summary and comparison tables. For examined power exchanges according to Table 5, some limitations in internal networks have been determined. Due to those limitations some exchange programs were not possible according to N-1 criteria. To solve that, decreasing of scheduled bulk power transfers has to be done using 100 MW steps approach. As a result maximum possible transfers according to N-1 criteria were calculated as shown in Table 5. Every scenario is calculated with and without single candidate line. Hence, each interconnection candidate line benefit and participation could be strictly defined. Because of the previously mentioned limitations in internal networks the new candidate lines have lower impact on maximum exchanges increasing. Table 4 List of Investment Projects for Studies consideration Figure 1. Existing and candidate interconnections in the region Project Type Voltage (kv) Countries Involved Status 2005 Mostar S/S 400 B&H, CRO, YUG In Ernestinovo S/S 400 CRO, YUG, B&H In Ernestinovo -Pecs OHL 400 CRO, HUN Option Zerjavinec S/S 400 CRO In Sombor S/S 400 YUG In Sombor - Pecs OHL 400 YUG, HUN Option Nis -Skopje 5 OHL 400 YUG, MKD Option Skopje 5 S/S 400 MKD In S.Mitrovica - Ugljevik OHL 400 YUG, B&H Option B. Luka-Zagreb OHL 400 B&H, CRO Option Bekescaba-Oradea OHL 400 HUN, ROM Option Isacha B/B 400 ROM Option Tirana - Podgorica OHL 400 ALB, MN(YUG) Option Tirana S/S 400 ALB Option Fierza - Prizren OHL 220 ALB, SER(YUG) Option Bitola - Florina OHL 400 GRE, MKD In Stip - Cervena Mogila OHL 400 BUL, MKD Option Stip S/S 400 MKD Option Skopje - Tirana OHL 400 ALB, MKD Option Maritza 3 - Hamitabat OHL 400 BUL, TUR In Maritza 3 - Filippi OHL 400 BUL, GRE Option Filippi - Babaeski OHL 400 GRE, TUR In Heviz - Cirkovce2 OHL 400 HUN, SLO Option Table 5. Bulk power exchange scenarios Winter peak From To Scheduled Maximum

5 exchange exchange UCTE TUR TUR,GR UCTE UCTE BUL,GR,ALB ROM,BUL,GR UCTE CENTR,Burs,ROM TUR,GR TUR,BUG CENTR CENTR,Burs BUL,GR,ALB ROM,BUL,GR CENTR er peak UCTE TUR CENTR,Burs,ROM TUR,GR Procedure for prioritization of the new candidate interconnection investment options has been defined and approved by TCG. Prioritization criteria are based on: power flows, power losses, security, participation in exchange scenarios and maximum transits. Economical criteria have not been considered in this Project phase. Inclusion of the economical criteria is expected in the following project phase. V CONCLUSION The regional transmission network planning project has been introduced under the sponsorship of the USAID using infrastructure of SECI initiative. Regional power system model has been created in PSS/E format. The main task of the project was to evaluate new interconnection lines in the region. Different bulk power exchange scenarios have been defined, examined and analyzed. Some limitations in internal networks have been detected. Maximum transit for each scenario has been calculated according to N-1 security criteria. Due to internal limitations, candidate interconnection lines have no significant impact on maximum exchanges increasing. A prioritization procedure was used to rank candidate lines, based on technical criteria. Economical criteria are expected to be included in the following project phase. VI BIOGRAPHIES Trajce Cerepnalkovski, born in 1953, graduated at University of Skopje, Faculty of Electrical Engineering. Affiliated with Macedonian Power Company (ESM) for 23 years, as Transmission planner, IT manager, Development and Investment Director. Current position with ESM-Head of the unit and SECI Projects Coordinator. trajce@esmak.com.mk Davor Bajs, born in 1970., graduated in 1994 at University of Zagreb, Croatia, Faculty of Electrical Engineering. He received his M.Sc. degree in at the same Faculty. His area of interests is transmission network planning and analysis. He has been working in Energy Institute Hrvoje Pozar, Zagreb since he graduated. dbajs@eihp.hr Goran Majstrovic, born in 1975., graduated in 1998 at University of Split, Croatia, Faculty of Electrical Engineering. He received his M.Sc. degree in 2001 at University of Zagreb. He has been working for Energy Institute Hrvoje Pozar, Zagreb since His area of interest is transmission planning and analysis. gmajstro@eihp.hr Nenko Gamov, born in Sofia, Bulgaria in 1947, graduated in M.Sc. in Electrical Engineering in 1971, Ph.D. in Electrical Engineering in He became associated professor in 1989, all at Technical University of Sofia. His current position is Senior Engineer in Transmission and Planning Department of Dispatching Center in NEK. ngamov@ndc.bg Nikola Rusanov, born in Karlovac (Croatia) in 1946, received B.Sc.EE in 1971 and M.Sc. degree in 1983 at Faculty of Electrical Engineering in Sarajevo, since 1971 employed in Power Company Elektroprivreda BiH, Sarajevo. He works on load flow and power system stability analysis. At the moment he is chairman of STC 38 BH CIGRE and member observer of STC CIGRE Paris. n.rusanov@elektroprivreda.ba Miroslav Vukovic, born in Sarajevo (BiH) in 1957, graduated at Faculty of Electrical Engineering in 1980, received M.Sc. degree in 1985, since 1994 employed in EKC Belgrade. He works on network analysis and planning problems, member of UCTE subgroup Network Modeling and Forecast Tools. miroslav.vukovic@ekc.co.yu Snezana Mijailovic, received B.Sc.EE. at University of Belgrade in 1990, preparing M.Sc. thesis, worked for Electrical Insitute Nikola Tesla, Belgrade in the period , works for Electricity Coordinating Center (EKC) since 1996 as head of the Research and Consulting Department. Her area of interests is technical and organizational aspect of electrical energy sector. In 2002 she became deputy general manager of EKC. sneza@ekc.co.yu Patrick D. Miller holds a B.Sc. degree in Engineering and a MBA degree in Finance, is a Registered Professional Engineer in Michigan, USA and has worked in the energy field for CMS Energy for 36 years. pmiller@cmsenergy.com