应用模糊神经网络实现故障测距

提出一种应用模糊神经网络进行输电线路故障测距的新方法。该方法具有很强的自适应和抗干扰能力。通过有导师的学习，模糊神经网络将自学会对故障电量的分析计算，完成线路故障的测距。仿真结果表明，经充分训练的网络可快速准确地定位故障，不受故障类型、过渡电阻及系统运行方式的影响。

NEW PRINCIPLE FOR DIRECTIONAL COMPARISON CARRIER PROTECTION OF EHV TRANSMISSION LINES

The increasing scale and complexity of power systems require high performance and high reliability of power system protection.Protective relaying based on directional comparison with power line carrier or microwave channels is the most suitable protection scheme for long distance EHV transmission lines and is widely used in power systems.The key element of such protection is a directional relay used to discriminate the fault direction.In order to overcome the disadvantages of conventional directional relays,the authors of this paper put forward the directional comparison carrier protection based on the artificial neural network(ANN).The protection is extensively tested using electromagnetic transient program (EMTP) under various electric power system operating and fault conditions.It is proved that the directional comparison carrier protection based on ANN,which can recognize various fault patterns of the protected transmission line(such as fault direction,fault phases etc.)correctly in any kind of operating and fault conditions and the whole process,is satisfactory for EHV transmission line protection.

基于 ANN 的超高压输电线路方向高频保护

人工神经网络所具有的信息分布式存储、大规模自适应并行处理、高度的容错性等特点是它们可用于模式识别的基础，特别是其学习能力和容错性对不确定性模式的识别具有独到之处。因此，文中提出了基于人工神经网络模式识别技术实现超高压输电线路方向高频保护的方法。通过电磁暂态仿真程序（ＡＴＰ）的全面测试，结果表明所实现的方向高频保护不仅能在各种复杂的运行方式和故障条件下正确地识别各种故障模式（如故障方向和故障相别），而且在整个时域上都能保证具有准确的识别能力，能够满足作为超高压输电线路主保护的全面要求。

浅谈企业定额的建立

企业定额的制定对施工企业走向市场,求得生存和发展具有重要意义,此文就企业定额的概念、主要特征以及制定原则等方面作了论述,为进一步控制投资、节省造价提出了建议。