Metering

Metering systems

A metering system refers to the set of equipment that measures energy flowing into a site. A metering system may comprise of current transformers, voltage transformers, test block, potential fuses, meter, datalogger and ripple relay.

It's important to understand the type of metering you have, so you can ensure your metering is compliant with certain standards set down by the electricity industry governing bodies. You also have some options as to how your meter is read.

Types of metering

There are basically two types of meter – Time of Use and Static meters. All Corporate customers have Time of Use metering by definition; however if you have multiple sites some smaller, residual sites may have static meters.

1. Time of Use Meter

A meter where energy measured is recorded discreetly for each half-hour (the unit in which electricity is bought and sold on the spot market. The half-hour periods are called intervals, and are stored electronically along with the date and time of the interval. These are retrieved electronically at a later date.

The part of a Time of Use meter that records the half-hourly intervals is called a datalogger. Most Time of Use meters have built-in dataloggers, but it is possible to fit an external datalogger onto a static meter to record half-hourly interval data.

2. Static Meter

The meter at your house is a static meter. In a static meter, the energy measured is recorded on a cumulative register (the dial you see on the front of the meter as on the picture, or sometimes a digital LCD screen) - as opposed to a Time of Use meter, where the energy is recorded and the meter zeroed every half hour.

There are common two types of static meters:

a. Single register – any energy consumed on a site is recorded on a single register.

b. Two register – any energy consumed on a site is recorded on one of the registers, depending on which one is active at the time ie day/night. Registers are switched on and off by an external switch such as a ripple relay.

A ripple relay is an electrical switch that is remotely controlled by the injection of a coded signal into the electrical network. Ripple relays are used to remotely switch load off and on – for example, your domestic electricity account may allow the network company to switch your water heating on and off at set times. This may be done through a ripple relay.

Compliance

The Electricity Governance Rules set out standards and performance obligations for metering.

Meter reading options

You can have your meter read by one of three methods:

Via cellphone
Downloading meter data via a cellphone is the most common and most effective option for reading your meter (providing your site has cellphone coverage, of course). It's the most timely and usually the most reliable (for example, It's not subject to interruptions through problems with your landline telephone system).

Via landline
While cellphone is the preferred option, if cellphone coverage is not available, meter data can be downloaded through a Direct Dial landline connection.

Manual reading
If no telephone coverage is available, manual reading (through an electronic connection to your meter) can be arranged. This method is less convenient than telephones and also more expensive due to its manual nature.