Vacuum Switching Technology and Components for Medium Voltage Your Guide

3AF0 outdoor circuit-breaker (live tank) SDV outdoor circuit-breaker (dead tank) 3EF surge limiter / 3EK4 surge arrester 2 Vacuum Switching Technology and Components for Medium Voltage · Siemens HG 11.01 · 2016

Vacuum Switching Technology and Components for Medium Voltage Medium-Voltage Equipment Catalog HG 11.01 · 2016 Invalid: Catalog HG 11.01 · 2007 Page Introduction to medium-voltage components Overview of medium-voltage components Switching devices, non-switching components Vacuum interrupter technology in detail Selection of components by switching applications Switching applications with undisturbed operation Switching applications with disturbed operation Ratings for medium-voltage equipment Stress caused by network operation Standards Medium-voltage equipment for indoor applications Vacuum...

Introduction to medium-voltage components Medium voltage is defined as the range above 1 kV up to and including 52 kV (alternating voltage). These voltage ratings are mainly used for distribution and industrial networks. Low voltage is defined up to and including 1 kV alternating voltage or 1.5 kV direct voltage. 1 Medium voltage (generation and distribution) 2 High voltage (transmission) 3 Low voltage In electrical power supply, most medium-voltage systems are operated between 10 kV and 40 kV. Due to the historical development of technology and the local facts, the ratings differ a lot from...

Overview of medium-voltage components Switching devices, non-switching components Switching devices Circuit-breakers Circuit-breakers are capable of making and breaking all currents both in disturbed and undisturbed operation; from small inductive and capacitive load currents up to the short-circuit current; and this under all fault conditions in the power system such as earth faults, phase opposition, etc. Outdoor circuitbreakers have the same applications, but are designed to withstand weather influences. They are mounted on the ground, on poles, or directly on overhead lines. Recloser The...

Overview of medium-voltage components Vacuum interrupter technology in detail Arc quenching During the galvanic separation of the contacts, the current to break produces a metal vapor arc discharge. The current flows through this metal vapor plasma until the next current zero. The arc extinguishes within the next current zero. The remaining metal vapor loses its conductivity after a few microseconds – the insulating capability of the contact gap recovers very quickly. With a recovery of about 5 kV / µs, the vacuum interrupter or the switching device can immediately control the applied voltage...

Overview of medium-voltage components Vacuum interrupter technology in detail Fixed terminal disc / connection bolt Insulator (ceramic, partly with additional external silicone insulation) Fixed contact Moving contact Shield Metal bellows Guide (bearing) Moving connection bolt Vacuum interrupter Radial magnetic-field contact Axial magnetic-field contact Contact support Contact disc Arcing ring Arcing direction Cup-shaped contact Arcing direction Spiral contact Vacuum Switching Technology and Components for Medium Voltage · Siemens HG 11.01 · 2016 7

Switching applications Appearing load Switching application © Current © Particularity © Remark Transformers unloaded loaded Furnace transformers Earth-fault reactors Compensation reactors High switching rate Transient recovery voltage with Also valid for neutral earthing transformers Generally no protective circuit required Overvoltage protection circuit to be configured individually Surge arresters are common practice Overvoltage protection circuit to be configured individually Static converters Small inductive currents Transient recovery voltage with high rate of rise Virtual current chopping...

Switching applications Switching applications with disturbed operation Appearing load Switching application © Current © Particularity © Remark Switching duties in case of short circuits Making on a short circuit High and low inductive currents Terminal short circuit Generator-supplied short circuit Transient recovery voltage with rate of rise < 6 kV / ps, high DC component, possible missing current zeros Overvoltage protection supplied short circuit Transient recovery voltage with rate of rise < 4 kV / ps limiting reactors Is. Transient recovery voltage with rate of rise < 10 kV / ps Double earth...

Ratings for medium-voltage equipment Stress caused by network operation Overview of system data Medium-voltage equipment must be selected for the stresses appearing at the respective place of use. The ratings of the components describe the maximum values the components can be used for. Rated voltage The rated voltage is the upper limit of the highest operating voltage for which the device is designed. It must be equal to or greater than the maximum appearing operating voltage under consideration of the permissible voltage fluctuations. The ratio between the rated voltage and the necessary withstand...

All devices are subject to national and international standards. The following table shows the main product standards; superior standards are not included. In addi- tion, Siemens switching devices are subjected to further tests in order to guarantee safe operation in long years of operation. In many countries, there are local standards that are mostly based on the international standards, but which contain some specific particularities. The main international standards are IEC (Europe) and IEEE (USA). Most of the users in Europe, Asia and Africa request lEC-based standards, while North America...

Medium-voltage equipment for indoor applications Vacuum circuit-breakers Application • For breaking resistive, inductive and capacitive currents in almost every application • U niversal installation in all customary medium-voltage switchgear types • A s single-pole or multi-pole medium-voltage circuitbreakers for all switching duties in indoor switchgear • Available with optional withdrawable module with and without earthing switch • Particular designs for special applications: –– For switching of generators –– For switching of contact lines (1- and 2-pole traction circuit-breakers) –– For frequent...