Real-time operation inevitably suffers from time to time from unpredictable situations concerning both the dispatch of generation and network management to which the dispatcher must respond immediately.
ČEPS prepares and regularly updates emergency plans to avoid and manage abnormal situations in the TS. A defence plan (addressing failure occurrance and spread) and a restoration plan (for the restoration of power supplies after a system blackout) form important parts of any emergency plan. The procedures and technical tools, including emergency communication, intended for the management of emergency situations are described below.
Dispatch of generation
Differences between electricity supply and demand or between the scheduled and actual balance of cross-border exchanges can occur at any time due to unexpected weather changes, inaccurate load prediction, failures at generating plants or changes in cross-border exchanges. In order to maintain reliable TS operation and the provision of system services, the ČEPS Control Centre monitors, on a continual basis, the expected load on the power system, scheduled cross-border exchanges and the current status of purchased ancillary services.
The following tools can be used by dispatchers to procure regulation energy:
Ancillary services (AnS) activation;
Balancing electricity market;
Purchase of regulation energy from abroad;
Emergency assistance from abroad; and
Contracts for output reduction or changes in consumption.
Network management for emergency situation prevention and tackling comprises long-term planning, the coordination of power line tripping and generating unit outage, the modelling of the day-ahead congestion forecast (DACF), reconfiguration, redispatch, the coordination of the various measures available and direct cooperation with foreign partners.
A number of special tools are available to the dispatcher to support decision-making in the above situations including:
Contingency analysis – on-line calculations performed via the control system which highlight potential power line overload due to the simulated outage of any system element;
Regional Awareness System – a system based on on-line data exchange with foreign partners; it provides information on the energy situation in neighbouring TSO areas and potential problems;
Programmes for redispatching and reconfiguration – programmes offering possible changes in network configuration or generation redispatching in situations where network overloading or the non-fulfilment of the N-1 criterion occurs;
Network calculation – calculations facilitating the analysis of a hypothetical situation in the TS following the intended action of the dispatcher.
Tackling emergency situations
In the event of an emergency situation within the Czech power system, the ČEPS Control Centre is entitled (in compliance with the Energy Act and Regulation 80/2010) to declare a situation intended to avoid a state of emergency and, in the worst-case scenario, declare a state of emergency in the Czech power system. Extraordinary tools available for tackling emergency situations include the Frequency Maintenance Schedule, the Switching-off Schedule and the Consumption Regulation Schedule.