Active Network Management (ANM) implementation
In order to control Active Network Management (ANM) connections WPD uses a third party system, which monitors thermal and voltage constraints, to calculate a required set point that will prevent any network violations. This set point is communicated to a Connection Control Panel (CCP), which is the interface between WPD and the customer’s site. The CCP interface with the customer’s equipment is via a four-channel analogue output module and the respective pins presented to the customer comprise:
- Real Power Upper Bound - Iout0/AGND*
- Real Power Lower Bound - Iout1/AGND**
- Reactive Power Upper Bound - Iout2/AGND
- Reactive Power Lower Bound - Iout3/AGND
*primary channel to be used for import control (demand connections)
**primary channel to be used for export control (generation connections)
Each channel is presented as a 4mA-20mA analogue 12-bit integer, with a 12mA value representing zero, 20mA representing full scale +ve, and 4mA representing full scale –ve. Customer equipment must therefore be capable of measuring and resolving the analogue mA signal accordingly.
The definition of “Full Scale” will be determined by a size category dependent on the greater of the customer’s maximum import or export capacity as follows:
- Up to and including 5MW: Full Scale is +/- 5MW (Real) and +/- 5MVar (Reactive)
- Greater than 5MW, up to and including 20MW: Full Scale is +/- 20MW (Real) and +/- 20MVar (Reactive)
- Greater than 20MW, up to and including 100MW: Full Scale is +/- 100MW (Real) and +/- 100MVar (Reactive)
For example, a 14MW generator, which would be on the +/-20MW scale, would receive a 6.4mA signal under normal conditions. If a constraint were identified and the export required to reduce to 8.5MW a 8.6mA signal would be sent, followed by a 12mA signal if full curtailment were required.
In addition, the panel presents both a “Stage 1” and “Stage 2” digital output, each comprising a normally open contact controlled by the CCP to be closed onto a customer-energised circuit. Upon receipt of a “Stage 1” signal the site must be fully constrained within 30 seconds. If this does not occur a “Stage 2” signal will be sent, upon receipt of which the G99 breaker must be opened.
Further, the panel requires both a “Stage 1 Confirm” and a “Stage 2 Confirm” digital input, each comprising a WPD-energised circuit (48V DC) onto which a customer-controlled normally open contact can be closed.
Commissioning of ANM connections
In order to connect an ANM site a number of additional steps are required to provide the necessary inputs and control. Details of the existing process can be found within WPD’s policies here.
To confirm the site will follow the presented set point, as described in the WPD ANM Implementation section, commissioning tests will be carried out. These will confirm steady operation
at a set point, ramp rates and correct escalation to “Stage 1” & “Stage 2” in the event of an issue. The process for commissioning an ANM site is detailed within the Customer Commissioning Process document.