OPERATIONAL PROCEDURES FOR CONNECTION OF AUTOPRODUCERS AND INDEPENDENT POWER PRODUCERS IN THE DISTRIBUTION NET

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1 - OPERATIONAL PROCEDURES FOR CONNECTION OF AUTOPRODUCERS AND INDEPENDENT POWER PRODUCERS IN THE DISTRIBUTION NET Camargo Dirceu B. 1. INTRODUCTION With the energy crisis lived by the Brazilian society in the year of 2001, there was an accentuated increase in requests of customers generation connection to the distribution net of the Brazilian power utilities. However, this was a little explored theme in the electric power distribution environment, being much more present in the extent of the transmission companies. Thereby, there was not a report of the procedures which should be adopted by the power utilities or by the new producers, being necessary to develop a process totally new, in an environment still little known and within an extremely scarce time, mainly for the need of Brazilian industrial development process continuation. It is needed to emphasize the importance of narrowing the relationship with the new producer, from the project evaluation to the implantation of local procedures and training application, in the field and in the Operation Center. In the extent of the distribution power utilities, the preparation and training of the responsible teams for the electric net operation, would be essential for the success of these connections and the increment of that new energy in the electric system. These stages are fundamental to guarantee the electric system integrity and the safety conditions of the teams involved with the several tasks executed in the distribution nets, which start to count with a new element capable to inject electricity in their cables. The objective of this article is to detail the adopted operating procedures to make possible the conecction of autoproducers and independent power producers to the distribution system, considering the following connection types: permanent parallelism with purchase of energy, permanent parallelism without purchase of energy and parallelism in ramp, with emphasis to their peculiarities and special characteristics. 2. DEFINITIONS 2.1. COGENERATION It is the simultaneous generation of thermal and mechanical energy, starting from a same primary energy source. The mechanical energy can be used in the work form (for instance, movement of mills in a sugar and alcohol industry), or transformed in electric power through an electricity generator. The thermal energy can be used as heat source for the industrial process. In Brazil, there was an accentuated growth of generations moved by diesel oil, mainly to assist industries in the emergency situation, due to the energy rationing. Another very used generation source is the biomass, as in the case of the sugar and alcohol industries AUTOPRODUCER It is the industry that owns energy cogeneration and, besides using the energy generated in its production process, it sells that energy to the market, elevating its income INDEPENDENT PRODUCER It is the producer that generates the energy but it is not classified as generator. It usually uses alternative energy sources, as biomass, thermal, wind, small hydroelectric plants, etc. and it sells that energy to the market SMALL HYDROELECTRIC PLANT - PCH It is a hydroelectric power plant of small size, classified in Brazil with a generation of less than 30 MW. 3. BRAZILIAN ENERGETICS COMPOSITION Generation Type Installed power 2001 (MW) Forecast 2004 (MW) Hydroelectric power plant % % Thermal power plant % % Nuclear power plant % % Alternative Sources (Wind, % % PCH, Biomass) SUBTOTAL % % Itaipú Import % % Other imports % % TOTAL % % Table 1 - Brazilian Energetic Composition 30 Source: ANEEL New Cases REAL EXAMPLE Total The following graph displays the growth of the connections 20 with autoproducers and independent energy producers in 15 the energy distribution utility ELEKTRO Eletricidade e Serviços S.A., in the São Paulo state, Brazil: BEFORE ELK_Camargo_A1 Session 4 Paper No

2 - the connection point between the two systems; - the grounding system; - the protection system; - the definition of the operational relationship between the producer and the distribution utility; Graph 1 - Connections evolution of independent producers or autoproducers connected to the distribution net. Source: ELEKTRO Eletricidade e Serviços S.A. 4. TECHNICAL ASPECTS OF THE AUTOPRODUCER OR INDEPENDENT ENERGY PRODUCER CONNECTION TO THE DISTRIBUTION NET The following illustration presents a typical configuration, simplified, of an industrial plant that owns generation connected to the distribution net, and that operates in parallel or separately to supply a part of its electric power consumption. Regarding the connection point, interlinked systems in high voltage represent a better condition from the protection of the connection point of view, because the impedance of the transformer decreases the short circuit contribution of the utility to a fault at the generator. At the generator grounding system, the resistance limits the value of the faults to the ground and it reduces significantly the current of the third harmonic generated. At the transformer, the connection in delta in the upper voltage side is to avoid the increase of the short circuit phaseground current in utilities and to avoid undesirable contributions in the system. From the protection point of view, the following ANSI functions are demanded from the producer: - 50/51 - overcurrent protection; directional overcurrent protection; undervoltage protection; phases sequence protection; frequency protection; synchronization; power reversion protection; overvoltage protection. Among those defined functions, some can be programmed to protect the connection. It is necessary a high selectivity between the producer system protections and the utility system protections. Usually, all of the system component equipments, on the utility side (lines and transformers), but also on the industry side (generator, transformers and loads), own protection devices, responsible for the detection and insulation of the equipment in a fault case. 5. OPERATIVE PROCEDURES 5.1. CONTRACTS Obeying the National Electric Power Agency - ANEEL legislation and the definitions of the Net Procedures, by the System National Operator - ONS, the electric power producer should hire the connection and the use of the distribution system of the local utility. The Operative Agreement, attached to the use and connection contracts, should contemplate all of the operational aspects related to the connection of the utility system with the energy producer. Fig. 1 - Typical configuration simplified From the operative point of view, some subjects need to be carefully analyzed, such as: 5.2. OPERATIVE AGREEMENT The Electric Brazilian System operation is executed according to the Operation Procedures Manual - MPO, part of the Net Procedures, established by ONS and ratified by ANEEL in January, However, that documentation, despite beeing supported by the other ANEEL resolutions, doesn't contemplate the ELK_Camargo_A1 Session 4 Paper No

3 regulation of the operation of distribution net connections between distribution utilities and electric power producers. Therefore, the standards documentation associated to the connection should be elaborated by the local utility, responsible for the distribution system operation. In this paper, it will be demonstrated the methodology used by ELEKTRO Eletricidade e Serviços S.A., distribution power utility in São Paulo state, Brazil Considering the individual characteristics of each connection the operational aspects involved should be evaluated individually. That evaluation implicates in visits to the generator plant, besides the electric project analysis. After that, a first version of the Operative Agreement is elaborated by the distribution utility and submitted to the electric power independent producer or autoproducer evaluation, with the following main topics: - DEFINITIONS In this item it is attempted to concentrate the whole terminology used in the operational relationships and in safety's documentation between the utility and the electric power producer. It is used a reference for the good understanding between the utility operation team and the electric power producer team, both in the pre-operation and post-operation aspects, and in real time as well. Examples: a) Connection Equipment Impediment Authorization - AI - It is a document used to register and to guarantee to the company, responsible for the services execution, the impediment of the connection equipment, in the conditions requested, formalizing the agreement of the companies involved in the impediment. b) Electric Power Autoproducer or Independent Producer Qualified Employee - It is the Autoproducer or Independet Producer employee, properly trained and enabled by the distribution utility, to perform the operation and maneuvers of the connection equipments, blockades and unblockades, as well as to carry on the operational relationships with the Operation Center. - GENERAL CONSIDERATIONS In this item are the operational premises of generic character, essential to the safety and the correct operation of the connection equipments. Examples: a) Any service (programmed or emergency) to be executed by the producer in its substation or transmission line, that needs disclosings, openings or equipments blockades at the utility should be supported by specific document AI, which formalizes the safety conditions between the two companies. b) The electric power producer should maintain at its command room a telephone, to make possible the operative contacts for the execution of the maneuvers, allowing permanent communication with the utility Operation Center, during the whole process. - OPERATIVE ORIENTATIONS It gathers the procedures for the relationship between the responsible areas for each operation stage. It defines which deals to be accomplished for the services programming, operation in normal regime and emergency, and it establishes all the stages of relationship between the utility team and the electric power producer team. Examples (extracted from the Operative Agreement between ELEKTRO Eletricidade e Serviços S.A. and the electric power Independent Producer USINA MOEMA): a) In normal cogeneration regime of USINA MOEMA with ELEKTRO, the parallelism should be made mandatorily through the USINA MOEMA circuit breakers MOE24-1 or 2 and, in no hypothesis, through the substation Paulo de Faria circuit breaker or circuit breakers of the Transmission Line Paulo de Faria/Riolândia, 69kV. b) The operational relationships between the USINA MOEMA and ELEKTRO, in real time, should be done directly between USINA MOEMA'S operator and Operational Center's operator. c) It will only be allowed that USINA MOEMA employees properly trained and enabled by ELEKTRO, operate and maintain operative contacts with the Operation Center, when USINA MOEMA is in cogeneration regime with ELEKTRO. d) For the programmed maintenances, USINA MOEMA should request with a minimum advance of 7 (seven) useful days of the disclosing date. The request should be made through the emission of the specific document AI, through fax or , from the USINA MOEMA office to the Operation Center. - CONNECTION OPERATION It defines the procedures for the generator connection or disconnection to the distribution net. Examples (extracted from the Operative Agreement between ELEKTRO Eletricidade e Serviços S.A. and the electric power Independent Producer USINA MOEMA): Procedures for the closing of USINA MOEMA's parallelism with the substation Paulo de Faria circuit breaker a) USINA MOEMA's Operator a.1) Contacts the Operation Center operator requesting authorization to perform the parallelism of the plant with ELEKTRO distribution system. b) ELEKTRO Operation Center Operator b.1) Confirms that the circuit breaker is closed and that the Transmission Line 69 kv Paulo de Faria/USINA MOEMA is energized in radial. b.2) Authorizes USINA MOEMA's operator to establish the parallelism. c) USINA MOEMA's Operator c.1) Verifies the voltage existence at the entrance of its substation, adjusting the generation voltage to a value whose difference in relation to the voltage of the ELEKTRO system, is not greater than 1KV. c.2) Adjusts the frequency generated to the value of the ELEKTRO system frequency, to assure proper synchronization conditions. 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4 c.3) Makes the synchronization of USINA MOEMA's generation with ELEKTRO system, through the parallelism circuit breakers MOE24-1 or 2. c.4) Contacts the Operation Center operator, informing the synchronization of the generation unit c.5) Maintains an excitement of the generation unit, so that the voltage in Transmission Line Paulo de Faria/USINA MOEMA stays around 72 kv. - OPERATIVE DOCUMENTS It establishes the correct use of the operative documentation to be exchanged between the utility and the electric power producer, for the warranty of the safety conditions during the execution of the works. In this section the fields that are in the documents should be totally described, with the respective completion conditions. - COMMUNICATION MEANS It should relate the communication channels between the electric power Autoproducer or Independent Producer and the distribution utility, considering all of the connection operative process stages, that is: pre-operation, real time and post-operation. - ATTACHES As essential attaches we have: - Maneuvers Unifilar Diagram of the connection equipments; - Qualified Employees list; - Model of the operative documentation to be used; - The parallel connection and disconnection with the system control table Having the electric power Independent Producer or Autoproducer agreed with the proposed document, the distribution power utilities should emit a definitive review, that it will be submitted to the training of the teams involved with the connection operation. 6. TRAINING AND IMPLANTATION With the conclusion of the preparation of the Operative Agreement, according to item 5.2.2, the local utility becomes responsible for applying a training in its team involved with the connection operation and in the electric power producer responsible team. That training should be applied in its own connection equipments, at the electric power Autoproducer or Independent Producer plant, contenting: - equipment operation safety conditions; - operational aspects included in the Operative Agreement; - effective standards in the utility related to safety and cogeneration; - practice of maneuvers; - operational deals; - operative documentation. After applying the training at the plant, the trained team becomes qualified to perform the operational deals and the exchange of operative documentation with the utility. The components list of that qualified team becomes part of the Operative Agreement. 7. CONCLUSION The electric power Independent Producers and Autoproducers connection to the distribution net is a reality in the Brazilian electric system. To adapt to the growth of that connection modality, the distribution utility needs to establish procedures for the evaluation and adaptation of the essential operative conditions to the perfect system operation. As demonstrated in this paper, the establishment of clear rules that contemplate the safety necessary conditions are fundamental to guarantee the connection success. The distribution utility has a commitment with the quality and continuity of the electric power supply to its customers. The Operative Agreement signature with the electric power Autoproducer or Independent Producer should consider those premises to minimize eventual penalization applied for the regulator organism. The success obtained by ELEKTRO Eletricidade e Serviços S.A., as told in this paper, can be useful as an example of the actions to be adopted by an electric power distribution utility. 8. AUTHOR Camargo, Dirceu B. dirceu.camargo@elektro.com.br 8.1. CO-AUTHOR Lopes, Carlos H. C. carlos.lopes@elektro.com.br 9. REFERENCES [1] ELEKTRO, 2002, Operative Instruction - " I-OPE-01 - Segurança na Operação e Manutenção do Sistema Elétrico ", Review 1, ELEKTRO, São Paulo, Brazil [2] ELEKTRO, 2001, Operative Agreement " I-OGC-05 - Operação do Sistema de Distribuição da ELEKTRO em Regime de Cogeração com a Usina Moema ", Review 1, ELEKTRO, São Paulo, Brazil [3] ELEKTRO, 2002, Norm " ND-63 - Conexão de Consumidores dos Grupos A2 e A3, Clientes Livres, Autoprodutores e Produtores Independentes de Energia ao Sistema Elétrico da ELEKTRO nas Tensões de Fornecimento de 69 kv, 88 kv e 138 kv - Critérios Gerais", Review 1, ELEKTRO, São Paulo, Brazil [4] ONS, 2001, " Aspectos Operaiconais da Interligação ELK_Camargo_A1 Session 4 Paper No

5 Garabi-Rincón (Interconexão Brasil-Argentina)", XVI SNPTEE - Production and Electric Power Transmission National Seminar, GOP/004 [5] Clementino, L.D., 2001, " A Conservação de Energia por meio da Cogeração de Energia Elétrica ", Ed. Érica, São Paulo, Brazil [6] REIS, L.B., 2000, " Energia Elétrica para o Desenvolvimento Sustentável ", 1 Ed. EDUSP, São Paulo, Brazil [7] REIS, L.B., 1998, " Geração de Energia Elétrica ", Tec Art Editora, São Paulo, Brazil [8] XAVIER FILHO, B.J., 2001, " Cogeração no Setor Sucroalcooleiro ", Enershow 2001 [9] [10] ELK_Camargo_A1 Session 4 Paper No