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Modifications to an existing connection

  • If you intend replacing or adding equipment of different technology to that presently in situ, then we need to be aware of your proposals as we may need to make alterations to the electricity system as a result of work that you are intending to undertake.

    When do I need to notify you?

    It is important to notify us if:

    • You are proposing to increase the electrical load required by your installation, or;
    • You are connecting additional equipment or changing the technology of equipment that may adversely affect the electrical characteristics of your supply.  For example if you are adding motors or welders that could affect the voltage, or storage devices that could adversely impact upon voltage and load profiles for the site.

    Can you refuse a request for additional of change of technology?

    We generally would not refuse such a request however a full assessment would be needed to ensure your proposals do not adversely affect others customers connected to the distribution system. We would also need to assess any potential impact upon the electricity system as a result of your proposals.  

    What information do you need me to provide about the proposed change?

    We would recommend you contact us regarding any change in equipment that could impact upon the electrical characteristics of your site.  The details of changes and details of equipment installed or removed can then be determined. Generally and as a minimum we would require details of exact equipment/technology changes to allow a suitable assessment of potential impact upon the distribution network.

  • Any changes to installed generation need to be notified to us ahead of connection to the network. 

    Why do I need to notify you?

    Increases in generation can lead to increased levels of voltage distortion (e.g. connection of inverter based generation), increased power flow and increased fault level on the distribution network.

    It is a requirement under the Connection Agreement terms and conditions that the Distribution Network Operator (DNO) is notified of any changes that could impact upon your connection and the distribution network.

    What information do you need?

    We would need to understand if your proposals will:

    • Increase the export capacity at your site;
    • Increase the fault contribution from your site;
    • Increase the harmonic and flicker contribution from your site;
    • Alter the connection figuration of your site.

    We will also need to understand if there are proposed alterations to the metering arrangements, the interface with our network and the responsibility for equipment from an upkeep and maintenance perspective.

    What will happen as a result of changing my generation?

    For decreases in capacity, we will agree to revise any connection agreement you have with us.  We are able to facilitate changes from the 1st day of the month following your notification of the change, provided you promptly sign and return the amended agreement.   

    For increases in capacity, works may be required on the distribution network to accommodate the change which may be chargeable to you. In addition we may need to know about changes to the equipment within your installation and the potential impact upon power quality and /or fault level.  We will ask you to submit an application for increasing your capacity and make a full assessment to determine any necessary works.

  • The maximum import capacity (MIC) and maximum export capacity (MEC) is measured in kVA and is a value agreed between WPD and the customer for the capacity of the connection.  This is stated in the connection agreement when applicable.

    Do I need to notify you if I wish to change my capacity?

    These MIC & MEC quantities, also known as the Authorised Supply Capacity (ASC) for import or export, may be included in an electricity supply contract.  Where there is a requirement to change these values, for example due to making changes to your installation (e.g. installing or removing equipment), you will need to contact us in advance to agree the change.

    What will happen as a result of changing my capacity?

    For decreases in capacity, we will agree to revise any connection agreement you have with us.  We are able to facilitate changes from the 1st day of the month following your notification of the change, provided you promptly sign and return the amended agreement.

    For increases in capacity, works may be required on the distribution network to accommodate the change which may be chargeable to you. In addition we may need to know about changes to the equipment within your installation and the potential impact upon power quality and /or fault level.  We will ask you to submit an application for increasing your capacity and make a full assessment to determine any necessary works.

    Can you refuse a request to change my capacity?

    We are unable to facilitate a decrease in capacity within 12 months of a previous reduction or new supply installation.  If you request a change within this period, we will advise you of this and provide you with a date from which you may request a reduction. 

    We will not refuse requests to increase capacity but we may be required to carry out works before the increase can take effect.  We will ask you to submit an application for increasing your capacity and make a full assessment to determine any necessary works. 
     

  • The fault level at any given point of an electrical network is the maximum current that would flow in the case of a short circuit fault at that point.

    Fault level is an important parameter of any power system network. The available short circuit current must be accurately determined to ensure equipment can be carefully selected. Protective devices for electrical distribution systems such as circuit breakers, protective relays and fuses, provide adequate protection and disconnect faults.

    In order to obtain magnitude of the short circuit current it is necessary to consider all possible sources which can feed into the short circuit e.g. generators and induction motors.

    What will/could happen as a result of changing my fault level contribution?

    An increase in fault level contribution from your site could impact upon the short circuit capability of electrical equipment and plant within your network and on the distribution network.  A reduction in fault level could impact upon protection sensitivity and therefore any changes whether an increase or decrease needs to be notified.

    What information do you need me to provide about the proposed change?

    We would recommend you contact us regarding any change in equipment that could impact upon the electrical characteristics of your site.  The details of changes and details of equipment installed or removed can then be determined. Generally and as a minimum we would require details of exact equipment changes to allow a suitable assessment of potential impact upon the distribution network.

  • Why do I need to inform you of harmonic contribution changes?

    Engineering recommendation G5/4 sets the levels for harmonic voltage distortions to be used in the process for the connection of non-linear equipment. The change or addition of non-linear equipment at your installation needs to be assessed in line with this documentation.  These Regulations seek to limit the voltage distortion present in distribution networks to levels below the immunity levels at which equipment function and performance are likely to be impaired.

    What could happen as a result of changing my harmonic contribution?

    An increase in harmonic contribution from your site could impact upon the voltage distortion on the distribution network which could impair the function or performance of equipment within your site and/or at other customer sites. Therefore the installation or change of any non-linear equipment needs to be notified to us at an early stage so that potential impact can be assessed.