Aplicação de religadores híbridos em redes de distribuição de energia elétrica

Abstract

The necessity to maintain the quality indicators of electricity supply, DEC (Equivalent Duration of Interruption per Consumer Unit) and FEC (Equivalent Frequency of Interruption per Consumer Unit), both required by ANEEL (National Agency for Electric Energy) has never been so imperative for the electric power utilities companies. Year after year these indicators become increasingly demanding. Besides, in a natural way, the electrical system only tends to grow and become more complex, consequently bringing more technical challenges to the Protection, Operation and Maintenance (O & M) areas of Distribution Networks (DN). A Distribution Network, also known as a feeder, when shows characteristics such as small dimension, densely charged and with a high level of short-circuit current in the substation busbar (SS), is an example of challenging condition to ensure coordination and selectivity between the circuit protection devices. This panorama is especially difficult for the protection when there is a consumer of Group A (e.g. 13.8 kV) connected at the end or near the end of this type of feeder. With the significant investments made in recent years by electric power utilities for the acquisition and installation of reclosers (RL) in the DNs, in practice, the number of reclosers operating only as a sectionalising switch (SECC) and not as a recloser or even as a circuit breaker, has also been growing. This "sacrifice" occurs mainly in cases where there is no coordination for phase overcurrent (ANSI functions 50/51), once for the earth/ground faults it can be assumed that there will always be coordination (ANSI 50N/51N functions). This resource is satisfactory for simple configurations of the RL-SECC type, however, it has major drawbacks when it involves two or more consecutive (or serial) SECCs in the feeder. Considering this scenario and the sophistication of the current protection relays used in the control cubicles of the reclosers, this work proposes a solution to the coordination and selectivity problem by making use of the logic programming resources in the relays, transforming the recloser into a hybrid device. This way, it operates as RL or SECC depending on the type of short circuit. The hybrid recloser, in addition to operating as a dual behavior device (RL / SECC), optimizing the use of this asset in the network, does not require any change in the device protection setting upstream (recloser or circuit breaker), nor does it depend on communication. In addition, it allows the automatic self-healing of healthy stretches, in line with safety practices (it does not increase the number of reclosing (ANSI function 79) of the upstream devices, it can be activated and deactivated locally or remotely, etc.), moreover being a concept not oriented to a specific recloser manufacturer. It is hoped, with this work, to bring a new perspective to the area of study of protection of electric power utilities companies and significant contribution with new practices of protection settings and the operation of reclosers in DNs.