engleski

Primary frequency control monitoring at grid control centers

Although participation of large power generation units in control area’s primary frequency control is obligatory by national grid codes, the actual practice shows that it is often disabled in power plants. Since this control causes small fluctuations of unit’s power production which influences planned hourly production and causes additional wear and tear of generators, plant’s owners/personnel find turn it off. This is more often in power systems where this service is obligatory, but non-profitable. Besides, due to quite large Continental Europe interconnection, smaller control areas such as Croatia, have a very small contribution in overall primary frequency control reserve. That reserve could be covered with just one or two units engaged in primary frequency control. Dividing instantaneous area’s primary control error among all large units within the area would result in such small required power changes of individual units that they would be within dead zones of units’ turbine controllers. On the other hand, each transmission system operator (TSO) is responsible for ensuring that required primary frequency control reserve is available at all time. To fulfil that requirement, TSO should have the means to continuously monitor total available primary frequency control reserve in its area and to assess control performance of individual generating units/power plants in case of frequency disturbances. The latter would be particularly important if primary frequency control reserve market was established. In Croatia, a step forward towards this concept was done several years ago with primary frequency control monitoring pilot project, which included two generating units at two hydro power plants. Monitoring system was implemented in National Control Center (NCC) of Croatian TSO. The experiences from this project are presented in this paper with the aim to contribute to better understanding of the monitoring process and to define guidelines for future control centers’ requirements and functionalities.

Primary frequency control; monitoring system; transmission system operator; power system

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