Participant Outage Plan
Northpower – Security of Supply Participant Outage Plan
Authorisation to receive direction and activate
Implementing rolling outages
TABLE 1 – Grouping of Load Types in Terms of Priority
Translating Savings Targets into an Operational Plan
TABLE 2 – An illustration (number of days in week) x (total hours duration)
Coordination with the Transpower System Operator
Grid Exit Points (GXP's) and Rolling Outages
Automatic Under Frequency Load Shedding (AUFLS) Requirements
Format of Operational Plan
Timeframes to respond to a Developing Event and an Immediate Event
Communicating the Operational Plan with the System Operator
Communicating Health Safety Issues Affecting Consumers and Retailers
Backup / Contingency Planning
Coordination with Grid Emergencies
Maintaining Performance Over Time
Monitoring and Reporting Performance against Targets
Authorisation to receive direction and de-activate
This plan complies with the Electricity Authority (the "Authority") Security of Supply Outage Plan (SOSOP). It advises the Authority and the public of Northpower's planned response to a declared "Supply Shortage Declaration" if issued by the Authority. It is not a plan to be used to recover from grid emergencies or localised disruption of supply where normal operational procedures apply. A foreseeable scenario where this procedure might be called into effect is during a low inflow spring and/or a drought summer, when low water levels in the main hydro lakes seriously reduce electricity generation capacity and action needs to be taken in order to conserve energy.
Northpower is required to maintain this outage plan up to date, so it is likely that changes will be made in future to reflect any material changes within the Northpower network and customer base. In the event that changes are made to the plan it will be resubmitted to the Authority for approval.
Northpower?s primary point of contact is: -
Network General Manager
28 Mt Pleasant Road
Tel: 09 430 1803, Fax 09 430 1817
The following personnel are authorised to put this plan into operational effect upon receipt of written notification from the Authority: -
- Network General Manager
- Network Commercial Manager
- Network Services Manager
- Network Operations Manager
Written communication from the Authority (email or Fax) must stipulate: -
- Declaration of Supply Shortage
- Reason / Circumstances Public Message (optional)*
- Issuing Authority Reference
- Named Authority & Signature
*If the Authority makes a supply shortage declaration, it may also decide to communicate the need to conserve electricity and warn about pending rolling outages through a coordinated media strategy. Under these circumstances, any public messages / statements from Northpower will be coordinated with the Authority. Northpower will broadcast messages via its website and/or telephony (faults line) to inform the public of current circumstances and will include any Authority messages as practicable.
- General Management – Network General Manager
- Commercial Management – Network Commercial Manager (and support team)
- Network Services – Network Services Manager
- Operations – Network Operations Manager (and Systems Control Operators / support team
- Implement and oversee the execution of this plan
- Liaise with police, civil defence, local authorities, etc
- Maintain accurate outage message on Faults Line (0800 10 40 40)
- Network Commercial Manager (and Commercial support team)
- Liaise with large industrial sites and critical infrastructure, keeping them informed
- Report performance against savings targets to the Authority
- Communications Manager
- Communicate with media
Upon receipt of written notification it is incumbent on the initiator of this procedure to contact the originator at the Authority and verify the instruction, then send him/her written acknowledgement of that instruction, and copy to all the other Northpower staff named above.
This part of the participant outage plan specifies the process for establishing how particular target levels of savings would be achieved for different types of events, including how 5%, 10%, 15%, 20%, or 25% savings targets might be achieved. Achieving up to 25% savings within the Northpower network poses particular problems because of the very high proportion of large industrial customer load supplied. Large industrial customers represent almost 50% of the Northpower annual energy supply. Applying the priority criteria from the SOSOP suggests that these loads need to be given priority. The requirement to maintain AUFLS means that the 25% savings target would then need to be made by rolling outages across approximately 30% of Northpower customer load and it would be necessary to cut most rural and residential customers off for most of the time.
Energy supplied by the network (excluding NZRC) is on average around 12,500MWh/wk. So target energy savings are in 5 blocks of 5%, ranging from 625MWh/wk (MAX) to 3125MWh/wk (MAX). An illustration of the likely impact on customers in order to achieve the prescribed energy savings under this plan is given in Table 2 below.
All 11kV feeders are listed, prioritised and grouped in an online reference document that has been compiled by Network Planning personnel, and is accessible to the Network System Control Operator for reference and for use with this procedure. There is also a Civil Defence / Northland Utilities „Lifeline? Contacts List to enable Northpower planners and operators to maintain contact with key personnel at other organisations.
Energy saving actions that would have relatively little impact (when compared to lengthy power outages over widespread areas) are: -
- Controlled hot water would be controlled more aggressively
- Switch streetlights off at, say, Midnight
- Use available generation wherever possible (hospital, etc) – by prior agreement, and funded by retailers
- Cut production or output
- Other measures? (all measures to be communicated in advance via media)
|Priority||Priority Concern||Maintain Supply to:|
Major hospitals, air traffic control centres, and emergency operation centres.
These facilities are protected by high priority usage supply agreements. However they generally have the means to support themselves and will not be exempt from planned measures to reduce consumption from the grid. In the event of a need to reduce power consumption, it may be feasible to use their local electricity generation plant for reasonable periods of time (yet to be agreed) in order to ease consumption from the grid.
|2||Important public services||
Energy control centres, communication networks, water and sewage pumping, fuel delivery systems, major ports, public passenger transport and major supermarkets.
Business and services that offer critical services that are highly dependent on continuous electricity supply will, more likely than not, maintain uninterruptable power supplies and have a means of local generation to continue limited operations.
Northpower has a list of such organisations and will contact each one individually to discuss foreseeable options prior to imposing power cuts that might otherwise cause problems.Facilities such as Council-operated wastewater pumping stations with minimal storage, and where no backup generation is available, must also have a „Plan B? should prolonged power outages be necessary to meet power reduction targets under this plan
|3||Public health and safety||
Minor hospitals, medical centres, schools, and street lighting.
Medical centres, where no acute / critical care procedures are affected by loss of power, and schools, should be able to withstand a normal rotation of power outage and will not be exempt from power cuts. In the event that rolling scheduled power cuts become unavoidable, Northpower will inform all schools and minor hospitals in writing and will aim to give at least 7 days advance notification of the high risk of power cuts.
Traffic lights will be inoperable during area-wide power outages; therefore the police will receive notice of planned outages likely to affect traffic lights so that they can plan accordingly.
Street lighting is something which the community might have to manage without during area-wide power outages, and there might also be a need to reduce the night hours of street lighting across the entire network, as an energy saving measure. This might mean street lights routinely going off at say, midnight, or 1am. The public will be notified of these intentions by media in advance of implementation
|4||Animal health and food production/storage||
Dairy farms, milk production facilities, chicken sheds and cool stores.
Northpower is very mindful of the requirements for electrical energy in dairy production, and the disruption to process plant if power fails for lengthy periods. Farms and processing facilities will not necessarily be exempt from power cuts, however extra consultation, planning and communication with farmers and processing facilities will take place to try to minimise wasteful disruption, and to reduce the risk of suffering being caused to livestock. For example, where practical, rolling cuts in rural areas will be timed outside normal milking times.
Commercial and industrial premises.
There may be times when production will be interrupted and this might be unavoidable if rolling power outages affect an entire area. Northpower will communicate plans and intentions to conserve energy via the media, and will take extra special care to communicate with, and plan around, critical industrial processes where unplanned interruption is likely to cause disproportionate financial damage and hardship to companies.
|6||Disruption to consumers||
The general public at home (and at schools and in the workplace) will be encouraged to take steps to withstand periods without electrical power. Specific guidance will be published in newspapers prior to power cuts being implemented as a means of conserving energy.
These statements will include such things as: -
Network Planners have produced a list of Feeders that have objective „shed? and „restore? priority rankings based on a weighted formula comprising the following elements: -
- Do Not Shed (essential supplies, including major ripple plants)
- Large Commercial
- Small Commercial
- Dairy Farms
- Critical Sites – Criticality ) as defined by Northland "Lifelines" group
- Critical Sites - Restoration Priority )
Using the above data, and relating it to the six groups of load types in terms or priority (Table 1), feeders have been grouped for scheduled disconnection and each group has constraints intended to minimise the impact to the industry / community that is fed by particular supplies. In „normal? times, constraints and durations of cuts would be sensitive to the particular needs of (the majority of) customers that will be affected by disconnection. In the exceptional operating regime anticipated in order to achieve the required energy savings, normal constraints and considerations will be largely ignored, and then it simply comes down to arithmetic in planning, and making the cuts as widespread and lengthy as is necessary based on operational data.
Table 2 is an illustration of the frequency and duration of rolling outages in the different priority groupings that will be necessary to make the savings targets.
|Group 1||Group 2||Group 3||Group 4||Group 5||Group 6||MWh/Week Saving|
|5%||-||-||-||-||5 x 4h||7 x 4h||625|
|10%||-||-||3 x 4h||5 x 5h||6 x 6h||7 x 6h||1250|
|15%||2 x 4h||3 x 4h||5 x 4h||7 x 5.5h||7 x 7.5h||7 x 9h||1875|
|20%||4 x 2h||5 x 3h||7 x 4h||7 x 6h||7 x 9h||7 x 12h||2500|
|25%||5 x 4h||6 x 4h||7 x 5h||7 x 10h||7 x 12h||7 x 15h||3125|
Load will be disconnected (and reconnected) in a controlled manner. Load reductions (and restoration) will be coordinated with the System Operator (Security Coordinator) in real time, before rolling outages are implemented and before restoration is commenced (including meeting any reasonable requirements of the System Operator to limit the rate of disconnection). In the absence of an alternative agreement with the System Operator, the rate of disconnection and restoration of load will be limited to no more than 25MW per 5 minute period.
Instantaneous power reduction will be achieved by switching off groups of feeders.
From the prioritised list of feeders detailed in Table 1 and illustrated in Table 2, Northpower has produced a confidential outage management plan for rolling power cuts across a mix of outage groups in a way that is designed to minimise disruption, and conforms to prior communications with critical organisations, industry and the System Operator.
The precise mechanism for these rotations is not for public disclosure because of security and public order considerations.
Rolling outages will be implemented on 11kV feeders from Zone Substations, rather than 33kV sub-transmission from GXP?s. The exception is Dargaville, which is on an 11kV GXP. The allocation of energy savings to particular GXP?s is something that will be reported on. Most affected might be Kensington (residential) and least affected will be the Oil Refinery load at Marsden Point GXP
Northpower?s AUFLS network reserve load is pre-configured, operated by frequency-sensitive relays hard-wired to 11kV feeder tripping circuits at Zone Substations. These cannot be reassigned as part of planned rolling power outages. In order to maintain AUFLS when implementing rolling outages, Northpower will only roll outages across AUFLS feeders to the extent that it remains possible to meet the requirement to have 32% of total load (net of NZRC) covered by AUFLS. This means that few, if any, AUFLS feeders will be able to be included in rolling outages.
The baseline for comparison and measurement of performance will be the energy consumed by the same „in scope? network load during the same weekday 52 weeks prior. In the comparison adjustments will be made for significant plant closures, new industrial demands, exceptional temperature differences, etc, to ensure that fair and reasonable comparisons are made. Adjustments (if any) will be detailed and justified to the Authority.
During any period of rolling outages directed by the Authority, information will be provided to the System Operator (Security Coordinator) in the form of a half-hourly profile for each day of the following week. The corresponding baseline half-hourly profile for the same weekdays 52 weeks prior will also be provided. An arithmetical comparison and comments will be included in the report which will be compiled and submitted daily to the System Operator, for the duration of the declared supply shortage together with the plan (ie target profile + adjustments) for a rolling week ahead.
Any expected change to this forecast for any grid exit point, of more than 20% for any half hour, will be reported to the System Operator (Security Coordinator) as soon as reasonably practicable.
Immediate Event: Immediately (eg blackout)
Developing Event: Upon receipt of notification from the Authority, Northpower would expect to have been involved in discussions leading up to the issue of the notice and would therefore be already implementing some measures to conserve energy demand. That is the reason why measurement of savings must be against energy usage for normal operations (baseline 52 weeks prior), rather than against a recent time when cutbacks are already being made.
Following a series of rolling outages, load will be restored in a controlled manner and coordinated with the System Operator (Security Coordinator). Northpower System Control Operators will use the prioritised list of feeders alluded to above, and detailed supplementary operational procedures as their reference documents when operating to this procedure. Feeders will generally be restored manually, one at a time, to minimise steps in load increases.
The System Operator will have knowledge of this plan and the supplementary operating procedures which make reference to all necessary communications and prioritisation.
Communications with the System Operator will generally be between Northpower?s Control Centre and Transpower?s Regional Operating Centre using Transpower?s TSX telephone system.
Arrangements for communication with a full range of critical, sensitive and important customers are in place within detailed operating procedures, the priority listings and Northland?s Civil Defence communications plan. If rolling power cuts are implemented there will need to be coordination and communication between all emergency management stakeholders, of which Northpower is one.
The plan will be worked through as detailed. Unexpected events and contingencies will be handled as part of normal operations. This is planned, rather than reactive, outage management. The public and all critical / industrial customers will have been forewarned.
Arrangements to manage Grid Emergencies (as defined in rule 1 of part A of the Rules) will take immediate priority over rolling outages.
Under frequency events are instantly responded to by Interruptible Load (IL) and then, if necessary, by AUFLS, which has been exempted from this procedure, and normal load building operations will follow on when the grid emergency has passed in order to restore the AUFLS load to its normal state of availability.
The rolling outages program will continue, once a Grid Emergency is over, if the Grid Emergency occurred during a period of rolling outages.
Northpower has half hour power logging at GXP?s that collect data and enables tracking and monitoring of all power outages. The target for the grid for all half-hour periods will be set at n% less than the corresponding period in the baseline set on the same day 52 weeks prior, with any particular adjustments for industrial load changes and/or temperature. Accordingly, Northpower System Control Operators will be able to observe the impact rolling outages have on demand relative to target levels, and will be able to use their judgement to modify the application of rolling outages to maintain savings at the target level.
A combination of half-hour metering and SCADA systems collect the power consumption data across the network to build the load profile. Comparison with half-hourly data from the same weekday 52 weeks prior, adjusted for changed industrial loads and/or temperature is reported and graphed on a daily basis. Near real time reports are also available to Northpower System Control Operators as required during operations.
An outage log maintained by Network System Control Operators will record: - Feeder No. Load, ICP Count, Time Off, Time On, Duration, Notes
Northpower?s quantified comparison of load profile against baseline and comments will be provided to the Authority on a regular basis (as specified by the Authority from time to time) and will provide sufficient commentary to show compliance (or otherwise) with this plan. Northpower will otherwise summarise their findings daily and report to the Authority weekly.
To revoke their Declaration of Supply Shortage, the Authority should notify one of the named key network personnel (see under "Authorisation to receive direction and activate").
Upon receipt of notification, the Authority will be issued with an acknowledgement from Northpower, copied to all (other) key personnel.
Network System Control Operators will then cancel planned power outages and restore all supplies in a controlled way in consultation with the System Operator, and using their normal operating procedures and guidelines.
In the case of a Developing Event, Northpower anticipates receiving advance notice from the Authority that it may need to make a supply shortage declaration and direct rolling outages. Ideally, this would be several weeks in advance of any direction to implement this plan and provide an opportunity for Northpower to communicate with the Northland public in order to mitigate the need for, and the effect of, large area power cuts on a regular basis. Northpower will initiate some or all of the following actions:
- Media liaison / press releases, etc during the run up period to inform and educate the public.
- Northpower Network staff will contact a full range of critical, sensitive and important customers, emergency services, local authorities and civil defence to explain how our outage plan affects them.
- As the plan is being called into action, the Communications Manager will:
- Create a banner on the home page of Northpower?s website, linked to further details on our plan and specific advice.
- Co-ordinate our communications with electricity retailers who in turn should communicate directly with consumers (particularly vulnerable consumers) via telephone, electricity bills or flyers, as appropriate.
- Send a press release to the media (local papers and radio stations)
- Produce a flyer for distribution to customers? mail boxes
- Distribute posters and quantities of flyers to community groups, local councils, local retailers and health care services.
- Include power saving tips and current information on „Twitter? social networking website.
- Include appropriate pre-recorded messages on the 0800 104040 „Faults Line?
- Use the Energy column in the Whangarei Leader (published monthly) on how this affects them and what they can do
- Place adverts outside of this in the local papers
- Use the 15 second radio adverts to notify power saving measures and to go to our website for further information.
In the case of an Immediate Event advance notice will not be possible, but Northpower will take all practical steps to coordinate with the public, electricity retailers and other agencies as soon as feasible.
This plan represents Northpower?s methodology for compliance with the Authority?s requirements. We reiterate that the plan is only for use in times of critical national power shortage.