Protection Principles for Future Microgrids

Abstract

Realization of future low-voltage (LV) microgrids requires that all technical issues, such as power and energy balance, power quality and protection, are solved. One of the most crucial one is the protection of LV microgrid during normal and island operation. In this paper, protection issues of LV microgrids are presented and extensions to the novel LV-microgrid-protection concept has been developed based on simulations with PSCAD simulation software. Essential in the future-protection concept for LV microgrids will be the utilization of high speed, standard, e.g., IEC-61850-based communication to achieve fast, selective, and reliable operation protection.

Improving the performance of power system protection using wide area monitoring systems

“…1) The introduction of directional overcurrent relays to replace the overcurrent relays that are prevalent in existing systems [59]; 2) The use of multi agent systems that can monitor multiple locations and make adaptive relaying decisions [60] 3) Enhanced pilot protection [61] 4) Enhanced converter response during faults [62] 5) Thermal protection relays that use an inference engine to combine dynamic ratings and coordination of DG to manage loading [63]; and 6) The use of negative sequence current dot protection (I 2 DP).…”

“…However, the smaller angular separation across a distribution network means that measurement of angles on the distribution network is more demanding than it is at the transmission level. A particularly important enabler for these new protection principles are micro-processor relays that can vary their settings easily and the IEC 61850 standard will be essential for fully realizing the capabilities of these devices and delivering the protection needs of future distribution systems [62].…”

From DC nano- and microgrids towards the universal DC distribution system - a plea to think further into the future

“…In a conventional LVdc, where the system capacitor is large, bus-bar protection is the main concern as the other protection categories can be easily incorporated with in the PEI. For conventional LVdc, commercially available dc protection devices can be used like molded-case circuit breakers, fast static switches [27]. Fuse is possible but it needs an overrated design of source PEI [26] to have high current for generating enough heat.…”

New Protection Scheme for Internal Fault of Multi-Microgrid

“…Recently, with the escalating energy demand and the pressure to reduce emissions, microgrid has gradually become a hot research topic in power system [1]. Microgrid is the medium or low-voltage power system, which consists of distributed generations (DGs), energy storage device, energy conversion device, loads, corresponding supervision and protection equipment [2,3].…”