ARTICLE / MAKALE capacity of the generator exceeds the minimum load of a section of network there is also the possibility that a ROCOF relay would not detect loss in the mains hence leading to the possibility of an islanded network. in this instance some RECs insist on inter-tripping between the source circuit breaker and the generator circuit breaker, this can add significantly to the cost of a grid connection. Commercial The cogeneration developer is driven by the desire to make profits by using gas to generate heat requirements and produce electricity so the interaction with the electricity system is often a second order consideration in the early stages of the project. The most succesfull developers usually have good relations with the utilities and initiate discussions as early as possible. Connection to the electricity network is often a significant barrier to development of cogeneration projects. in the UK, Regional Electricity Companies (RECs) have a statutory obligation to maintain a safe and reliable system. This obligation allows them to dictate the terms of a connection so that it will not compromise this obligation. A REC is also obliged to make its network available to third parties for the transfer of electricity and a developer has the option to refer a connection dispute to the regulator if he feels he is not being treated fairly by a REC. in this case the regulator would determine whether the charges being put forward by the REC are fair and reasonable. This option is however time consuming and is seldom used by cogeneration developers. Many of the developers interviewed cited examples where RECs had quoted extremely high grid connection costs which had subsequently been negotiated down to much lower prices (often less than 50% of the original quote). in some cases the utilities appeared to be being deliberately obstructive quoting for work that was unnecessary or could be avoided with relatively minor changes to the system. Several developers complained of inconsistency between different RECs and also between different local offices of the same REC. Key points that were raised by a number of developers were; • Communication was cited as a major problem when dealing with some utilities, there were numerous examples of problems where letters, faxes and telephone calls were not replied to or where there were a series of requests for further information often over several months. • Fault levels regularly being quoted as higher than the developers believed them to be, leading to a requirement either to up-grade switchgear or limit fault level contribution by fitting line reactors. A number of instances were quoted where initial estimates had been found to be excessive by subsequent detailed system studies. Some questions were raised about the techniques used to estimate fault levels � COGENERATION WORLD & Renewable Energy (contained G74 for the UK). The fault level problem is exacerbated by the policy of down-rating old switchgear, adopted by some utilities. • Loss of Mains Detection and the potential for network 'islanding' is an issue taken very seriously by many utilities often leading to what developers consider excessive protection schemes incorporating intertripping. • Sharing of Costs equitably is another issue which comes up regularly, both in terms of the utility contributing towards the brought forward cost of replacing equipment and other users who may in the future benefit from the up-rated system. Commercial procedure tor agreeing a connection: The negotiation of a generation connection follow the steps listed below, the exact procedure may vary slightly from REC to REC. 1. Preliminary enquiry 2. Generator technical information to REC 3. REC carries out necessary system studies 4. REC makes a connection offer to generator including; • Connection Offer Letter, covering work to be carried out and cost • Draft Connection Agreement • Draft Supply Agreement 5. Negotiations 6. Acceptance of connection offer letter, which may require an initial payment 7. Preparation of Agreements 8. Completion of Agreements and lnvoicing Connection charges Connection charges are usually made up of three parts, the connection charge, the repair and maintenance charge and the replacement of assets charge. The operation and maintenance element may be paid monthly or annually but is often capitalised and paid upfront. Connection agreements The connection agreement between the REC and the generator covers the technical requirements and costs associated with connecting the generator to the disribution network. it also covers compliance with the Distribution Code and any site specific technical requirements for safety and network performance. GAS This isssue should not be overlooked when most of the new capacity is gas fireci and gas distribution is not yet liber-
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