An adaptive protection scheme in active distribution networks based on integrated protection

Abstract

A considerable increase in the penetration of distributed generation (DG) to the distribution networks leads to a higher possibility of malfunction of present protection schemes of these systems. One of the major problems caused by higher levels of DG penetration is the reduction of the relay reach or relay access. This problem relatively relieves using adaptive overcurrent protection techniques but in certain conditions, the minimum relay access reduces to less than 20 percent of line length, in the presence of DGs and adaptive current protection cannot be used. In this paper a combined adaptive protection method is presented, which applies overcurrent and undervoltage protection simultaneously. Function of the protection system improves because of different action areas of these two types of protection. The feasibility of the proposed method authenticated through simulation.

An inverse‐time low‐impedance protection design for feeders in active distribution networks

“…Analyzing the case illustrated in Fig. 2, the impedance calculated by R1 for a fault beyond Busbar 2 is greater than what actually occurs [11]. Therefore, the tripping time of ITLI relays will increase especially when the utility grid operates as an infeed source, as shown in Table III.…”

“…Besides, the use of impedance is immune to complex operation modes and varying fault currents. Considering the bidirectional current flows caused by DGs, it is essential for the relays to be equipped with directional elements [11].…”

“…The MI sensed by the primary protection is always smaller than that of the backup protection even if there are DGs within the area [11]. Consequently, (2) can be simplified as…”

“…With the advantage of reliability, offline setting has to compromise on sensitivity and speed, especially in ADNs. With the existing ICT infrastructure, adaptive setting is available to adjust setting values by acquiring network information of ADN in real-time mode [4,11]. It is able to enhance the sensitivity and detection capability of ITLI relays without a high requirement on the communication system.…”

“…Moreover, the performance of protection using differential components is susceptible to errors and mismatches among current transformers [8]. Adaptive protection, with the aid of information and communication technology (ICT) and advanced measurement techniques (AMTs), has the capability of adjusting settings according to local information or network topologies [10,11] protection schemes did not solve the probable maloperation during setting the switch or failure of communication links. In Ref.…”