Minqiang Hu

Design and realization of regional power quality monitoring system

Power quality monitoring is the necessary condition that makes power supply in good working order. This paper presents a kind of new system that can monitor regional power quality. The system adopts the standard of PQDIF as the power quality data norm, expert system to analyse the status of regional power quality and the communication way of GPRS to transmit data. First of all, through this system the power quality manager can check the power quality status of each monitoring station by network from time to time, so we can analyse in time and reflect overall power quality level. Secondly, through the monitoring track record and statistic of power quality accident, the power supply and consumers both can define respective power quality administration obligation, so this system can also provide evidence which effectively settles the dissension because of power quality. Also it can monitor actual power quality of customers and is useful to establish a green electric power system.

A new CIM-based cross-platform graphic system for power system applications

In accordance with CIM standard (IEC 61970-301 ~ IEC 61970-303) [6-8], this paper presents a new graphic system for power system applications. This system, which is base on cross- platform design, is extensible and general-purposed. With the effective combination of CIM and cross-platform, this system can satisfy the needs of most power system applications. The characteristics of this system include the simplicity of the class hierarchies, the convenience of extension, and the ease to build up large application. It provides a useful reference for other CIM applications which needs to run on multiple platforms other than a single platform.

Discrete consensus-based distributed secondary control scheme with considering time-delays for DC microgrid

To ensure stable and optimal operation of DC microgrid, a three-level based hierarchical control strategy is proposed which consists of primary, secondary and tertiary controls. Usually, the primary control is performed locally without communication, the higher levels, however, can be either centralized or distributed. Considering the risks brought by centralized control, such as surviving central node or link failures, this paper proposes a distributed secondary control strategy for DC microgrid which is designed by Discrete Average Consensus Algorithm (DACA). In this paper, the controller embedded the distributed strategy will communicate with their neighbors through Low Bandwidth Communication to obtain average voltage of the whole system or power flow of grid-connected converter. Through the proposed novel strategy, the secondary control objectives such as reference power control, equal load sharing, voltage regulation will be realized in distributed means. Furthermore, the influence of communication delay to the strategy is studied at length, and the effectiveness and robustness of the proposed strategy are verified through detailed simulations.

Design of a Microgrid with Low-Voltage Ride-Through Capability and Simulation Experiment

A microgrid with low-voltage ride-through capability is designed. The designed microgrid avoids operating in unplanned islanded mode during an asymmetric ground fault which occurs in the low voltage distribution network and supports fault recovery for distribution network. Furthermore, compared with the traditional microgrid topology, the proposed microgrid topology also saves a lot of power electronic devices. The simulation results with PSCAD/EMTDC show that the microgrid can keep the distributed generations and loads operate normally when an asymmetric ground fault occurs in the low voltage distribution grid. It can also increase the active power output according to the requirement of the distribution network to support the distribution network fault recovery.