For a x - directed line current with lengh much smaller than a wave length , the e - field pattern on coordinate planes in 3 - d space in the region from much smaller than line length to one or two wave length , the synthesized pattern by summation of the field of many line segments of hertz dipoles is independent of the number of segments , i . e . same field as a single hertz dipole 以水平面上三角形甚小于波长线电流为例，分割为若干小段之赫芝偶极所加总合成在三度空间任意座标平面上距离从甚大于线长到一两个波长区域之电场场型与分割小段数量无关，即等同于一单一赫芝偶极之场型。
This paper analyzes the study and developmeni of the distfibuted power line protection & monitoring device on abroad and home . based on the demand of power depwtment , a full distfibated multifunctional protection & monitoring device faced the distributed line is studied . this instrument not only can perform functions of scada system , but also integrate the functions of the distance protection and three sects line current protection 本文分析了国内外配电线路微机保护和测控装置的研究和发展状况，针对现有电力部门的需求，设计并实现了一种面向配电线路的全分布式的微机保护和测控装置，该装置不仅实现了电力系统的实时测控和三段式电流保护功能，而且还率先集成了配电线路的微机距离保护。
Its test results indicate : voltage mode inverters with high frequency link have the advantages such as high frequency electrical isolation , simple topology , two - stage power conversions , high power density , bidirectional power flow , good line current waveform , low audio noise , high converting efficiency , and high input power factor etc . this kind of converter lay the key technical foundation on new type high power density , high efficiency and low cost asi 设计的1kva270v 10 % dc / 115v400hzac单极性移相控制双向电压源高频环节逆变器原理试验表明,这类逆变器具有高频电气隔离、电路拓扑简洁、两级功率变换( lfac / hfac / lfac ) 、功率密度高、双向功率流、音频噪音低、变换效率高、网侧功率因数高等优点,为新一代高功率密度、高变换效率、低成本航空静止变流器奠定了关键技术基础。
The prototype test results indicate : voltage mode and current mode ac - ac mode ac / ac converters with high frequency link have the advantages such as high frequency electrical isolation . simple topology , two - stage power conversions , high power density , bidirectional power flow , good line current waveform , no audio noise , high converting efficiency , and high input power factor etc . this kind of converter lay the key technical foundation on new type regulated sinusoidal ac power supply , electronic transformer , ac regulator , and wave converter etc 试验表明，这类变换器具有高频电气隔离、电路拓扑简洁、两级功率变换( lfac hfac lfac ) 、功率密度高、双向功率流、无音频噪音、变换效率高、网侧功率因数高等优点。为新一代正弦交流稳压器、电子变压器、交流调压器、同频波形变换器的实现奠定了关键技术基础。
For a x - directed line current with lengh much smaller than a wave length , the e - field pattern on coordinate planes in 3 - d space in the region from much smaller than line length to one or two wave length , the synthesized pattern by summation of the field of many line segments of hertz dipoles is independent of the number of segments , i . e . same field as a single hertz dipole 以水平面上向甚小于波长线电流为例，分割为若干小段之赫芝偶极所加总合成在三度空间任意座标平面上距离从甚大于线长到一两个波长区域之电场场型与分割小段数量无关，即等同于一单一赫芝偶极之场型。
The current source ac / ac converters with high frequency ac link have the advantages such as simple topology , two - stage power conversions , bidirectional power flow , high frequency electrical isolation , good line current waveform , strong load adapting ability and suit for low power conversion fields . the correction and advance of these converters are verified by the simulation and test results 这类换器具有电路拓扑简洁、两级功率变换( lfac hfac lfac ) 、双向功率流、高频电气隔离、网侧电流波形好、负载适应能力强、适合于小功率变换场合等特点。
