SKOLTECH Project: Distributed adaptive load shedding scheme against stability loss and electrical lines overloading in power systems, 2015-2017

Most of the difficulties in electric power system operation are caused by electrical grid overloads. An overload (a case of power or current in grid element exceeding the limit, stated for secure operation, and originating a potential congestion) can appear as a result of missteps of personnel, but more likely due to sudden disturbances (emergency opening of lines belonging the same cut-set, generation tripping or protracted short circuit at receiving subsystem, etc.).

Considering the length of high-voltage electric networks and the presence of long-distance transmission lines in the Unified Power System of Russia, the maintenance of the system stability in case of disturbances is a topical problem. Until now, one of the widespread ways to solve this problem has been the special load shedding schemes in the receiving subsystem in case of an emergency in one of the long-distance lines connecting the transmitting subsystem to the receiving one. This scheme has been activated in an emergency under the threat of system stability loss, depending on a certain emergency situation.

Historically, the considered load shedding schemes have been aimed at the disconnection of substations supplying power to large power system sections including consumers various in terms of their capacity and requirements for power supply reliability. Today, this approach is unacceptable since the consumers’ equipment sensitive to power supply interruptions suffers serious damage as a result of power outages initiated by their automation.

To implement the distributed adaptive load shedding scheme, it is suggested (provided its operation principles are maintained) to distribute the load to be shed among non-essential consumers at the level of feeders in the distribution network monitored for the overload of the network facilities. In this case it is necessary to adapt the distributed load shedding scheme to the current operating conditions. Smart technologies can be used for implementing this scheme.

The following main results of the Project are expected:

-        Today’s challenges to distributed adaptive load shedding.

-        Algorithms of distributed adaptive load shedding, which are to be developed, tested and proved with real power systems schemes, providing for the actual topology and operation conditions the calculation of optimal amount, composition and order of priorities of load to be shed, when either stability loss is imminent, or distribution network experiences overcurrent conditions.

-        Assessment of studied power systems peculiarities and the developed automation impacts on those peculiarities.

-        Suggestions for power systems and assessment of opportunities and prospects of distributed adaptive load shedding schemes.