The basic functions of LV switchgear: Difference between revisions
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{{Menu_LV_switchgear_functions_and_selection}} | {{Menu_LV_switchgear_functions_and_selection}} | ||
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The role of switchgear is: | |||
*Electrical protection | *Electrical protection | ||
*Safe isolation from live parts | *Safe isolation from live parts | ||
*Local or remote switching | *Local or remote switching | ||
}} | |||
National and international standards define the manner in which electric circuits of LV installations must be realized, and the capabilities and limitations of the various switching devices which are collectively referred to as switchgear. | National and international standards define the manner in which electric circuits of LV installations must be realized, and the capabilities and limitations of the various switching devices which are collectively referred to as switchgear. | ||
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are provided by specific devices (lightning and various other types of voltage-surge arrester, relays associated with contactors, remotely controlled circuit-breakers, and with combined circuit-breaker/isolators… and so on) | are provided by specific devices (lightning and various other types of voltage-surge arrester, relays associated with contactors, remotely controlled circuit-breakers, and with combined circuit-breaker/isolators… and so on) | ||
{| style="width: 793px; height: 171px | {| class="wikitable" style="width: 793px; height: 171px" width="793" | ||
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| '''Electrical protection against''' | | '''Electrical protection against''' | ||
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| '''Control''' | | '''Control''' | ||
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*Overload currents | *Overload currents | ||
*Short-circuit currents | *Short-circuit currents | ||
*Insulation failure | *Insulation failure | ||
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*Isolation clearly indicated by an authorized fail-proof mechanical indicator | *Isolation clearly indicated by an authorized fail-proof mechanical indicator | ||
*A gap or interposed insulating barrier between the open contacts, clearly visible | *A gap or interposed insulating barrier between the open contacts, clearly visible | ||
| | |||
*Functional switching | *Functional switching | ||
*Emergency switching | *Emergency switching | ||
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{| | {{Manual_TOC | | ||
* [[LV switchgear functions - Electrical protection]] | * [[LV switchgear functions - Electrical protection]] | ||
* [[LV switchgear functions - Isolation]] | * [[LV switchgear functions - Isolation]] | ||
* [[LV switchgear functions - Switchgear control]] | * [[LV switchgear functions - Switchgear control]] | ||
}} | |||
[[ru:Основные функции низковольтной распределительной аппаратуры]] | [[ru:Основные функции низковольтной распределительной аппаратуры]] | ||
[[zh:低压开关设备的基本功能]] | [[zh:低压开关设备的基本功能]] | ||
Revision as of 13:10, 15 November 2013
The role of switchgear is:
- Electrical protection
- Safe isolation from live parts
- Local or remote switching
National and international standards define the manner in which electric circuits of LV installations must be realized, and the capabilities and limitations of the various switching devices which are collectively referred to as switchgear.
The main functions of switchgear are:
- Electrical protection
- Electrical isolation of sections of an installation
- Local or remote switching
These functions are summarized below in Figure H1.
Electrical protection at low voltage is (apart from fuses) normally incorporated in circuit-breakers, in the form of thermal-magnetic devices and/or residual-currentoperated tripping devices (less-commonly, residual voltage- operated devices - acceptable to, but not recommended by IEC).
In addition to those functions shown in Figure H1, other functions, namely:
- Over-voltage protection
- Under-voltage protection
are provided by specific devices (lightning and various other types of voltage-surge arrester, relays associated with contactors, remotely controlled circuit-breakers, and with combined circuit-breaker/isolators… and so on)
| Electrical protection against | Isolation | Control |
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Fig. H1: Basic functions of LV switchgear
| Contents |
ru:Основные функции низковольтной распределительной аппаратуры zh:低压开关设备的基本功能
