IEC/TR 61000-3-13-2008 电磁兼容性(EMC).第3-13部分:限值.不平衡装置对MV、HV和EHV动力系统的连接用排放限值的评估

标准号：IEC/TR 61000-3-13-2008
中文标准名称：电磁兼容性(EMC).第3-13部分:限值.不平衡装置对MV、HV和EHV动力系统的连接用排放限值的评估
英文标准名称：Electromagnetic compatibility (EMC) - Part 3-13: Limits - Assessment of emission limits for the connection of unballanced installations to MV, HV and EHV power systems
标准类型：L06
发布日期：1999/12/31 12:00:00
实施日期：1999/12/31 12:00:00
中国标准分类号：L06
国际标准分类号：33.100.01
引用标准：IEC 60050-161
适用范围：This part of IEC 61000 provides guidance on principles which can be used as the basis fordetermining the requirements for the connection of unbalanced installations (i.e. three-phaseinstallations causing voltage unbalance) to MV, HV and EHV public power systems (LVinstallations are covered in other IEC documents). For the purposes of this report, anunbalanced installation means a three-phase installation (which may be a load or a generator)that produces voltage unbalance on the system. The connection of single-phase installationsis not specifically addressed, as the connection of such installations is under the control of thesystem operator or owner. The general principles however may be adapted when consideringthe connection of single-phase installations. The primary objective is to provide guidance tosystem operators or owners on engineering practices, which will facilitate the provision ofadequate service quality for all connected customers. In addressing installations, thisdocument is not intended to replace equipment standards for emission limits.The report addresses the allocation of the capacity of the system to absorb disturbances. Itdoes not address how to mitigate disturbances, nor does it address how the capacity of thesystem can be increased.Since the guidelines outlined in this report are necessarily based on certain simplifyingassumptions, there is no guarantee that this approach will always provide the optimumsolution for all unbalanced load situations. The recommended approach should be used withflexibility and judgment as far as engineering is concerned, when applying the givenassessment procedures in full or in part.The system operator or owner is responsible for specifying requirements for the connection ofinstallations which may cause unbalance on the system. The disturbing installation is to beunderstood as the complete customer’s installation (i.e. including balanced and unbalancedparts).Problems related to unbalance fall into two basic categories.• Unbalanced installations that draw negative-sequence currents which produce negativesequencevoltages on the supply system. Examples of such installations include arcfurnaces and traction loads (typically connected to the public network at HV), and threephase installations where the individual loads are not balanced (typically connected at MVand LV). Negative-sequence voltage superimposed onto the terminal voltage of rotatingmachines can produce additional heat losses. Negative-sequence voltage can also causenon-characteristic harmonics (typically positive-sequence 3rd harmonic) to be produced bypower converters.• Unbalanced installations connected line-to-neutral can also draw zero-sequence currentswhich can be transferred or not into the supply system depending on the type ofconnection of the coupling transformer. The flow of zero-sequence currents in a groundedneutral system causes zero-sequence unbalance affecting line-to-neutral voltages. This isnot normally controlled by setting emission limits, but rather by system design andmaintenance. Ungrounded-neutral systems and phase-to-phase connected installationsare not, however, affected by this kind of voltage unbalance.