Search

As wind penetration level into power systems increases, provision of frequency support from wind plant is anticipated to become a requirement in grid codes. In addition to the virtual inertial response, two different approaches to delivering droop response from wind plant are presented and compared in this paper. The combination of droop and inertial response from wind plant has been assessed for a frequency time series. Simulation results show that the proposed approaches to delivering combined droop and inertial response can provide superior performance to either inertial or droop response alone.

This study proposes a day-ahead optimal energy dispatch model for integrated energy system based on AC/DC interconnected infrastructure. In the infrastructure, micro-turbines turn high-frequency AC power into industrial-frequency AC power and incorporate it into the energy system's power system. Within the process, waste heat is sent into the waste heat boiler and lithium bromide chillier to interconnect with the heating and cooling systems. DC battery and photovoltaic generations connected with the energy system's power grid through the inverter are used as the flexible energy storage and power generation unit to build an autonomous integrated energy system based on AC/DC interconnection. In the optimisation model, the goal is set as system's lowest daily operation cost and lowest energy consumption. The constraints include system operation constraints and equipment constraints. Simulation results show that by performing the schedule made by the dispatch model, the operating efficiency of various types of AC/DC equipment in the energy system has been improved, energy waste scene has been reduced significantly and energy consumption in the energy system is reduced by 16% compared with other energy supply structure without AC/DC interconnected infrastructure under traditional schedule strategies.

This paper proposes a day-ahead optimal economic dispatch model for building Combined Cooling, Heat and Power (CCHP) system based on centralized energy storage infrastructure. In the model, the loads are met by the centralized energy storage equipment directly, and the storage equipment are charged by varieties of energy supply devices in the energy station of the building CCHP system. The model is solved by the interior point method with Hessian matrix iteration. Simulation results show that by performing the schedule made by the dispatch model, the storage status of the centralized energy storage fluctuates in large dynamic range by flexible charging and discharging and the daily operation cost of the building CCHP system decreases remarkably compared with other traditional schedule strategies. DOI: http://dx.doi.org/10.5755/j01.eie.24.4.21478

The application of electric power system transmission line protection based on traveling-waves or transient components suffers maloperation in case of single-phase earth fault. When single-phase earth fault happens, the system can still run for 1 or 2 hours because the phase voltage is still symmetry, and the ground current of fault phase is small. But single-phase earth fault will cause the increase of non-fault-phase's voltage. Long time of grounding operation will easily make fault expand to two points or more earth short circuit, and even lead serious interphase short circuit fault. Therefore, in order to prevent more serious fault caused by single-phase earth fault, it is necessary to find out the fault line and ground fault lines as soon as possible. The analysis result in this paper conforms well to the meteorological observations and zero-sequence current detection data of Empirical mode decomposition (EMD). And these results provide useful reference for the discriminant method of fault line work in power system. According to the differences, the paper proposes a method identifying single-phase earth fault based on Empirical mode decomposition. AutoCAD simulation results proved the method is feasible.