New development in relay protection for smart grid

Abstract

This series of papers report on relay protection strategies that satisfy the demands of a strong smart grid. These strategies include ultra-high-speed transient-based fault discrimination, new co-ordination principles of main and back-up protection to suit the diversification of the power network, optimal co-ordination between relay protection and auto-reclosure to enhance robustness of the power network. There are also new development in protection early warning and tripping functions of protection based on wide area information. In this paper the principles, algorithms and techniques of single-ended, transient-based and ultra-high-speed protection for EHV transmission lines, buses, DC transmission lines and faulty line selection for non-solid earthed networks are presented. Tests show that the methods presented can determine fault characteristics with ultrahigh-speed (5 ms) and that the new principles of fault discrimination can satisfy the demand of EHV systems within a smart grid.

New protection scheme for internal fault of multi-microgrid

“…The pre-and post-fault measured admittances of B terminal are: Combining (13)- (16), it is known that the measured admittance amplitudes have the following relationship:…”

“…In addition, if the DG penetration reaches a certain level, the protection cooperation will also be interfered. Meanwhile, the amplitude change of the measured pre-and post-fault admittances of C terminal cannot be estimated directly with (15) and (16).…”

“…In summary, the existing schemes cannot effectively solve multi-microgrids protection. There are two main problems: First, the control strategies of the DGs which have a large impact on the analysis of fault characteristics [16,17], are ignored in most protection schemes. Second, the majority of the existing work focus on a single microgrid, with the interconnection and interaction among the adjacent microgrids not taken into consideration.…”

Wide area measurements based fault detection and location method for transmission lines

“…The electric power is delivered from generation sources to distribution system through the transmission system. Faults occurring on any section of the transmission system will disturb or even interrupt the power delivery [1][2][3]. Thus, when faults occur on the network, it is vital to quickly and accurately pinpoint and isolate the faulted section so that the remaining network can continue operation.…”

Faulty phase active power characteristics‐based adaptive single‐phase reclosing schemes for shunt reactors‐compensated wind power outgoing line

“…Most large‐scale wind power bases in China are located far from load centers . Consequently, wind power‐generated electric power is frequently delivered through long‐distance, high‐voltage transmission lines.…”