Connection to the utility network: Difference between revisions

From Electrical Installation Guide
(Text modified (guide 2015))
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{{Menu_MV_and_LV_architecture_selection_guide}}
{{Menu_MV_and_LV_architecture_selection_guide}}
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The main configurations for possible connection are as follows (see '''Fig. D8 '''for MV service):  
The possible solutions for the connection of an installation to the utility network are the following:


*LV service,
* Connection to the LV network for small and medium size installations requiring less than 400 kVA. Fixing this limit is always under the responsibility of the local utility managing the LV network
*MV single-line service,
* Above this previous limit, connection to the MV network with either LV or MV metering. LV metering is generally authorized for installation including a single MV/LV transformer not exceeding the rated power limit fixed by the utility, generally around 1250 kVA.
*MV ring-main service,  
*MV duplicate supply service,
*MV duplicate supply service with double busbar.


Metering, protection, disconnection devices, located in the delivery substations are not represented on the following diagrams. They are often specific to each utilities company and do not have an influence on the choice of installation architecture.<br>For each connection, one single transformer is shown for simplification purposes, but in the practice, several transformers can be connected.(MLVS: Main Low Voltage Switchboard)
The possible connections to a MV utility network are the following, (see '''Fig. D8, D9 and D10):'''


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- MV single-line service,<br>
- MV ring-main service,<br>
- MV duplicate supply service, including two load break switches equipped with an automatic change over,<br>
- MV dual supply service with two independent connections to the utility and two bus bars connected with a bus tie. The two utility incomers and the bus tie are equipped with an automatic change over.


[[File:FigD08.jpg|none|500px]]
Comparison of this four modes of connection are summarized in '''Fig. D7'''
'''''Fig. D8:'''&nbsp;MV connection to the utilities network''  


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For the different possible configurations, the most probable and usual set of characteristics is given in the following table: <br>
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<br>


{| class="wikitable" style="width: 65%; height: 187px"
{| class="wikitable" style="width: 65%; height: 187px"
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! Characteristic to <br>consider  
! Characteristic to <br>consider  
!  
!  
! Simple-line  
! Single-line  
! Ring-main  
! Ring-main  
! Duplicate supply  
! Duplicate supply  
! Duplicate supply <br>with double <br>busbars
! Dual supply
|-
|-
| Activity  
| Activity  
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| Any  
| Any  
| Any  
| Any  
| Hi-tech, sensitive <br>office, health-care  
| High tech, sensitive office, health-care
| Any
| Very sensitive installations
|-
|-
| Site topology  
| Site topology  
| Single building  
| Single building  
| Single building  
| Single building  
| Single building
| Single or several buildings
| Single building
| Single or several buildings
| Several buildings
| Single or several buildings
|-
|-
| Service reliability  
| Service reliability  
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| Standard  
| Standard  
| Enhanced  
| Enhanced  
| Enhanced
| Very high
|-
|-
| Power demand  
| Power demand  
| &lt; 630kVA
| &lt; 400 kVA
| ≤ 1250kVA  
| ≤ 1250kVA  
| ≤ 2500kVA
| Any
| &gt; 2500kVA
| Any
| &gt; 2500kVA
| Any
|-
|-
| Other connection constraints  
| Other connection constraints  
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| Low density urban area  
| Low density urban area  
| High density urban area  
| High density urban area  
| Urban area with utility constraint
| Dedicated measures taken by the utility
|}
|}


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'''Fig. D7:''' Comparison of the modes of connection


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<br>

Revision as of 10:57, 5 December 2014


The possible solutions for the connection of an installation to the utility network are the following:

  • Connection to the LV network for small and medium size installations requiring less than 400 kVA. Fixing this limit is always under the responsibility of the local utility managing the LV network
  • Above this previous limit, connection to the MV network with either LV or MV metering. LV metering is generally authorized for installation including a single MV/LV transformer not exceeding the rated power limit fixed by the utility, generally around 1250 kVA.

The possible connections to a MV utility network are the following, (see Fig. D8, D9 and D10):

- MV single-line service,
- MV ring-main service,
- MV duplicate supply service, including two load break switches equipped with an automatic change over,
- MV dual supply service with two independent connections to the utility and two bus bars connected with a bus tie. The two utility incomers and the bus tie are equipped with an automatic change over.

Comparison of this four modes of connection are summarized in Fig. D7


  Configuration
  LV MV
Characteristic to
consider
Single-line Ring-main Duplicate supply Dual supply
Activity Any Any Any High tech, sensitive office, health-care Very sensitive installations
Site topology Single building Single building Single or several buildings Single or several buildings Single or several buildings
Service reliability Minimal Minimal Standard Enhanced Very high
Power demand < 400 kVA ≤ 1250kVA Any Any Any
Other connection constraints Any Isolated site Low density urban area High density urban area Dedicated measures taken by the utility

Fig. D7: Comparison of the modes of connection


ru:Подключение к питающей сети zh:与上级网络的连接

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