Applied Mechanics and Materials Vols. 644-650

Abstract: Introduces the use of ANSYS software provides streaming command language APDL written to General Procedures, and the General Procedures for switching power supply in a bridge circuit, by changing the parameters of the circuit can change the topology of the circuit, through simulation experiments, for the same circuit topology, using a common procedure than the GUI user interface modeling using ANSYS modeling time can be shortened to provide more than five times, illustrates the universal validity and effectiveness of the program, with great practical value.

Abstract: ‘SIM’ is the abstraction of ATM Switching Architecture Simulator which is developed by Stanford University based on time-slot. It’s produced to simulate ATM network. With the SIM, users can simulate the ATM switchboard in accordance with their needs on Linux platform. Multi-core CPU programming technology enable programs parallelized and achieve high improvement on performance. Therefore we bring this idea to develop a parallelized switch simulator called PSIM in this paper.

Abstract: The impacts of wind disturbance on voltage regulation and frequency regulation of power system were studied. The opinion that the regulation of power flow on the tie lines between the grids constrains the integrated capacity of wind power was put forward. Based on the real condition of Inner Mongolia power grid, an engineering practical method was put forward to calculate the integrated capacity of wind power under this constraint. The relationship between wind power and spinning reserve and the impacts of other related factors on the capacity of wind power were studied as well. The impact of wind disturbance on voltage stability where the wind farms are located was studied.

Abstract: A new type of substrate structure Electronic Enhance Collector IGBT (EEC-IGBT) was proposed, and the working principle was introduced in this paper. Compared with conventional IGBT, the substrate of EEC-IGBT was divided by the groove structure composed of oxide and aluminum. Finally, simulation analysis about the EEC-IGBT performance influence by structural parameters was given. The simulation results showed that the turn-off loss of EEC-IGBT was reduced 30% compared with CS-IGBT in the same condition voltage.

Abstract: This paper presents a new unit commitment model to solve the uncertainty of wind and load. The chance constrained programming is introduced in this paper. The uncertainty of wind and load is expressed as their prediction error. Considering their different characteristic, wind prediction error is indicated as a fuzzy variable, while load prediction error is represented as random variable. Different confidences reflect the different satisfaction of the constraints. Finally, example analysis shows that the proposed model is feasible and effectiveness.

Abstract: Recently, static var generator has been widely applied to substations all over China, mainly adopting indoor mounting and outdoor box-type substation (or color plate housing) mounting. As SVG is popularized, people gradually find out that the current mounting ways are not suitable for the actual environment of many substations (especially rural power grid). Large land coverage, big overall loss and complex maintenance have become the main factors that restrain further popularization of SVG. A new SVG structure is proposed. SVG body and mounting are combined, applied to a rural power grid substation successfully. Compared with ordinary SVG, it features small land coverage, reduced loss and maintenance quantity and higher stability.

Abstract: In recent years, power companies in different provinces have equipped the rural power grid substation with SVG, which has effectively resolved the problems of rural power grid such as low voltage and great fluctuation. Since SVG is a new 3G dynamic reactive compensation technology, people don’t know its compensation feature well. SVG control parameters are not configured according to the operation rules of the rural power grid substation.SVG shall undergo field test before commissioning in order to better resolve the problem of low voltage. Electrical property of the system to be compensated is known through the interaction between SVG and the system, thus determining the actual compensation mode and control parameters of SVG, thus achieving the best compensation effect.

Abstract: Before commissioning, SVG first requires a separated excitation process: network voltage charges the capacitor on DC side in each H-bridge power module via the starting resistor (IGBT in all modules shall lock impulse). After charging, SVG has enough power for dynamic var compensation of the system. This paper introduces fundamental functions of the starting resistor in SVG, analyzes the influence of starting resistor selection on safe operation of the device, raises the principle of selection and conducts simulation verification by using of PSCAD.

Abstract: SVG is a device parallel on the power grid for dynamic reactive power compensation, is a product of best performance and mature technology in the third generation dynamic reactive compensation technology so far. Thanks to power unit module series structure and PWM technology, compared with multiple SVG, chain SVG has high capacity, low loss, simple maintenance. But more complicated in control, indirect current control technology and direct current control technology are adopted. This paper utilizes PSCAD simulation software to build a chain SVG direct current controller model according to mathematical model of the chain SVG, simulates SVG compensation with inductive load and capacitive load, so as to verify advantages of fast tracking speed and stable control of direct current controller.

Abstract: As the representative of 3G dynamic reactive compensation technology, the chain SVG voltage has advantages of high-grade and high compensation capacity which mainly owe to the structure that each phase of conversion chain consists of a plurality of H-bridges in cascade. Although the DC side capacitor is not the core device in H-bridge, it has the job of providing DC voltage source during H-bridge circuit conversion. DC side capacitance affect not only the operation reliability of chain SVG, but also equipment cost and operation loss, so it should be selected reasonably. This paper introduces the role DC side capacitor plays in H-BRIDGE. PSCAD is used for simulated contrast analysis of chain SVG with different capacitances, and raises the criteria for DC side capacitance selection. Finally, the correctness of the criteria is verified based on the actual operation data of the field equipment.