| Abstrakt: |
Currently, low-capacity power plants, connected to distribution networks of medium voltage class near electricity consumers, are increasingly being used. At the same time, the integration of distributed generation (DG) objects into distribution networks leads to the emergence of a set of issues associated with the implementation of relay protection: power flows through power lines in both directions; the ratio of operating currents and short-circuit currents significantly depends on the operating mode of generating stations included in the distribution network; multipoint feeding of the short circuit point can occur; modes untypical for distribution networks can occur, including swinging and asynchronous run. It should be noted that distribution networks, as a rule, in most cases are equipped with simple overcurrent non-directional protections. The conventional approach to calculating relay protection setpoints loses its effectiveness, as a result of which the sensitivity and selectivity of protection decreases, and situations arise when it is impossible to select universal setpoints for all modes of operation. Thus, it is necessary to develop adaptive relay protection systems that would take into account all possible variations in the operation modes of the distribution network, generating stations, and consumers and would adjust the parameters of the operation of their functional components. In the practical implementation and use of systems that automatically calculate and adjust the setpoints of relay protection and automation, there are a number of tasks that require compulsory study: the setpoints of the same protections from different manufacturers may differ in semantics and, in some cases, qualitatively and quantitatively (especially important for differential protections); in addition to calculation, coordination of variations in setpoints in protection devices located at different objects is required; to reduce the time for calculating modes and setpoints, it is required to limit the area of the considered network by generating equivalents for the external electrical network with updating their parameters online. By using the generated model of the electrical network, the modes are calculated. The results of the calculation of the modes are subsequently used to calculate the parameters of the protection operation and verify the sensitivity. Following that, the operation parameters grouped by modes are adaptively adjusted in the RPA devices. [ABSTRACT FROM AUTHOR] |
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