Generating installations connected to ActewAGL’s distribution system must comply with all statutory and regulatory requirements and Standards, including but not limited to:
- AS/NZS 3000 Wiring Rules
- AS 4777 Grid connection of energy systems via inverters
- AS/NZS 61000 Electromagnetic compatibility (EMC)
- ActewAGL’s Electricity Connection and Distribution Standard Customer Contract
ActewAGL may disconnect any generating equipment from their distribution system if ActewAGL considers, on reasonable grounds, that:
- the equipment is dangerous to ActewAGL’s staff or representatives, or other persons
- the continued operation of the equipment poses a threat to the integrity of ActewAGL’s distribution system or other customer’s electricity supply
- specified testing is not conducted as described in this document.
All enquiries regarding the installation and connection of alternative sources of low voltage supply must be directed to ActewAGL.
The installation of the inverter and protection equipment must be approved by ActewAGL prior to installation. The customer must provide all appropriate documentation at the time of application for connection, including, but not limited to:
- single line diagram of the complete installation, including the Direct Current (DC) and Alternating Current (AC) sides of the inverter
- all earthing arrangements and connection point details. This should also include details of either earthed or floating DC circuitry
- full description of all protection equipment installed, including Type Test information and results verification of compliance with anti-islanding, voltage transients and harmonics as well as details of all settings or ratings equipment certification including appropriate test results. This should include evidence acceptable to the Department of Fair Trading in NSW for compliance with minimum safety requirements for electrical equipment categorised as “non-declared electrical articles”.
The customer shall make provision for metering equipment suitable for the purpose of the installation. The metering arrangement will be approved by ActewAGL prior to connection to the network.
Subject to the requirements of the Electricity Metering Code, ActewAGL will supply any standard metering equipment required. The customer shall pay the difference in cost for any non-standard equipment requested by the customer. Non standard metering includes, but is not limited to:
- electronic and/or bi-directional meters
- additional meters
Metering equipment must be installed in a manner and location that meets the requirements of the Service and Installation Rules Clause 4.3, 4.4 and 4.5, Appendix A3, Provision for Service Equipment in Single Domestic and Small Installations and Drawing 8911-321.
All wiring must comply with AS/NZS 3000 Wiring Rules and installed to meet the requirements of ACTPLA. All earthing arrangements must also meet ACTPLA requirements. ActewAGL will not connect the installation to the network without prior approval from ACTPLA.
All parallel generation sources should be connected to the customer’s electrical installation at a location adjacent to the ActewAGL electricity meter. Any variation to this location must be discussed with ActewAGL and approved prior to installation. The method of connection will depend on the metering arrangement as determined in clause 4.
The generation system must be installed on a dedicated circuit and all circuit cabling must conform to the requirements of ACTPLA and be capable of carrying the full rated output of the system.
The customer must install a generator supply main switch at the main switchboard unless approval for an alternative location has been granted by ActewAGL. The customer must include a double-pole DC circuit breaker between the generating unit and the inverter.
The generator supply main switch and the installation main switch(s) must be lockable or sealable to facilitate safe isolation. Refer to the single line diagram at the end of clause 8.
7.1 Islanding
Islanding is the situation where an inverter maintains a supply to the distribution system during a distribution system supply outage. Such outages may be planned (maintenance) or unplanned (blackouts).
Islanding creates serious safety issues for personnel working on the installation or the distribution system. It also creates quality of supply problems for other customers and the possibility of equipment damage.
All protection equipment associated with a Parallel Generation source must be designed, installed and tested to ensure that islanding cannot occur.
Protection equipment must include both “active” (anti islanding) and “passive” systems.
7.2 Active protection (anti islanding)
Active anti islanding protection must isolate the generation source from ActewAGL’s distribution system in the event of a distribution system supply outage.
Any anti islanding protection must be an approved method such as “frequency drift”. This method locks the inverter to the distribution system frequency as a reference. If distribution system supply is not present, the inverter frequency generator must shift away from the nominal 50Hz, thus tripping the Over / Under frequency protection. It is recommended that the direction of frequency drift be downwards. Alternative methods must be demonstrated to, and accepted by, ActewAGL prior to approval.
Three phase installations shall have protection and monitoring devices in each phase. Protection and monitoring of only one phase, or between two phases is not acceptable.
7.3 Passive Protection
In addition to active protection required under clause 7.2, the customer’s generation installation must have the following minimum protection (in the inverter):
- Over/under frequency
- Over/under voltage
- Over current and short circuit protection.
If the inverter protection is not considered adequate, ActewAGL may require the installation of additional protection. Where required, such backup protection shall be installed in an interconnection protection panel (outside the inverter) and must include:
- Over/under frequency
- Over/under voltage
- circuit breaker
Over/under voltage and frequency protection settings should be negotiated with ActewAGL within the limits specified in AS 4777 and the following Table.
TABLE 1 — OVER / UNDER PROTECTION SETTING LIMITS
| |
Minimum |
Maximum |
| Frequency |
48 – 50HZ |
50 – 52HZ |
| Voltage |
200v |
270v |
Protection devices must be set and calibrated by a recognised calibration laboratory to the satisfaction of ActewAGL. Settings may be either factory set or site programmable.
7.4 Security of Protection Settings
Where the inverter protection system has settings that may be changed via a keypad or switches, adequate security such as a suitable lock or password system must be employed to prevent tampering or unauthorised changing of these settings. All setting changes must have prior approval from ActewAGL.
7.5 Isolation Time
The combination of active and passive protection must operate within two seconds after loss of the distribution system supply under all load conditions. The inverter must remain disconnected from the distribution system until the reconnection conditions of Clause 7.7 have been met.
7.6 Disconnection
Disconnection due to the operation of any of the above protection must be via open contacts that break all active conductors (disconnection by semi-conductor switch alone is not acceptable).
7.7 Automatic Reconnection
Automatic reconnection of the generation system to ActewAGL’s distribution system must only occur if the distribution system voltage and frequency are within the protection limits specified in Clause 7.3 and these conditions have been maintained for a minimum of one minute, or as agreed with ActewAGL.
8.1 Installation testing
The installing contractor must carry out in-service testing of the inverter protection systems at the time of installation using a test method acceptable to ActewAGL. The test results must be recorded and a copy provided to ActewAGL prior to final approval.
8.2 Re-verification testing
The customer must arrange for a suitably qualified person to conduct in-service testing of the inverter protection systems at regular intervals. Such testing shall be conducted at intervals not exceeding 5 years and the results provided to ActewAGL. Any system not tested within the prescribed time, or that does not meet the requirements of the test procedure shall be immediately removed from service and shall not be reconnected without ActewAGL approval.
8.3 Recommended Anti-Islanding Test Procedure
An approved test procedure is outlined in Appendix B of AS 4777.3. Other test methods may be used with prior ActewAGL approval.
Similar procedures to test backup protection (if installed) should be followed with prior ActewAGL approval.
The customer must install clear and indelible labelling on all relevant parts of the installation. As a minimum labelling should be placed:
- On the switchboard that has generation facilities connected to it.
- Where approval has been obtained to connect the generation facilities on the customer’s side of the connection point; on all switchboards including the main switchboard and distribution board(s) upstream of distribution board where private generation plant is connected.
Labels should indicate:
- the existence of an alternative source of supply
- the sections of the electrical installation it can supply
- the point of control
- the conditions under which the alternative source may be operated
- the conditions of connection and suitable operating conditions
- the actual type of generation source installed, as particular generation sources have varied electrical characteristics.
Acceptable samples of labels are included below.
The following drawings form part of this publication: 8911-321 Permissible Meter Locations Domestic Installations