超长回采工作面供电设计研究及应用实践

为解决长距离供电与大功率负荷供电双重问题,满足供电需求,在工作面供电方案设计中,综合考虑长距离供电电压降、变频供电稳定性问题,通过对综采工作面设备供电负荷需求进行统筹规划,合理进行供电分配,从电缆、开关、高压防爆开关、变压器、电器设备开关的配套选型,各供电线路的负荷分配及电器设备布置等方面进行研究,最终解决超长工作面大功率负荷配电的问题。

真双极直流配电网有功-电压分布式二级控制策略

采用下垂控制的真双极直流配电网存在负荷分配不合理以及正负极电压不平衡问题,导致换流器利用率降低、额外损耗增加,并且影响系统稳定性。为了实现负荷合理分配以及抑制正负极电压不平衡,提出了一种真双极直流配电网有功-电压分布式二级控制策略。该策略按照第二级控制功能将电压源换流器(VSC)分类,交换相邻VSC间的信息。在此基础上,逐步迭代得到相应的功率和电压收敛值,并计算得到电压调节量。由此进一步改变下垂控制参考电压值,从而实现负荷的合理分配以及抑制电压不平衡。最后,在PSCAD/EMTDC中搭建了真双极直流配电网模型,仿真结果验证了该策略的有效性和可靠性。

Analysis on Regional Power Grid Load Characteristics and Rational Allocation of Capacity Load Ratio

The reasonability of the adopted capacity load ratio numerical value in urban power grid planning determines the economy of planning level yearly power grid.Too large capacity load ratio will result in the increasing investment in the early period of power grid construction, however, too small capacity load ratio will make the power grid have poor adaptability, affecting the power supply. Reasonably determining the adopted regional power grid capacity load ratio quantitative numerical value in planning has a strong guiding significance for constructing reliable and economic power grid and preventing power grid from excessive advance or lagging behind the load development. This paper, through the statistics and analysis of a certain regional power grid 2010-2012 three years＇ power grid daily load characteristics and the investment benefit evaluation of three years＇ 220KV power grid individual project, makes a preliminary analysis and puts forwards the specific advice on the reasonable values of power ~rid 35-220KV power transformation capacity load ratio.

通过“节奏”训练提高蝶泳运动成绩

少儿学习蝶泳技术的关键是掌握正确的动作节奏。重视、掌握合理快速蝶泳动作节奏，不仅节省体力，而且可以加快游速。对建立具有个人特点的技术风格具有重要意义。