Advanced communications: The no.1 reasons to install new meters
An electric industry survey by Newton-Evans Research indicated that the No. 1 reason electric utilities are upgrading high-end meters is to take advantage of advanced communications capabilities. Many utilities are using these advanced capabilities to improve the frequency of communication and accessibility of their metering information.
Deployment of high-end electronic revenue meters began about 30 years ago. Since then, we have seen great advances in the communications technologies used by electric utilities. The first electronic meters of the 1970s provided ‘communications’ capabilities that simply emulated those of electromechanical meters – specifically pulse inputs/outputs, or KYZ (as they are known in the ANSI metering community). Each KYZ pulse indicated a fixed amount of energy, e.g. 1.8 watt-hours in secondary units. These KYZ outputs were typically connected to external pulse recording devices or to SCADA RTUs. Many of these installations exist today in systems that use electronic meters to send energy information to SCADA RTUs with KYZ pulses.
In the 1980s, dial-up modems became inexpensive enough to be used in high-end electronic meters. This was one of the first remote reading technologies to be widely implemented. In addition to facilitating remote reading, dialup modems enabled frequent retrieval of load profile data. Instead of waiting a month to retrieve pulse recorder data, the electric utility could now retrieve meter data as often as needed – weekly or even daily.
This capability can be very important for large industrial loads. Retrieving load profile data frequently can help utilities detect metering problems, such as loss of a voltage input from a potential transformer, much sooner. Similarly, a loss of communication such as a failed telephone line can be detected and corrected before the monthly billing date. Dialup communication has become one of the most common and very important forms of high-end metering communication, especially for large loads over 1 MVA.
In the 1990s, more utilities started using wireless technologies to emulate circuit-switched wire-line communications. Wireless technologies allowed remote meter reading in situations that would otherwise require expensive line installations, such as crossing a parking lot to reach the meter. Analog cellular and now digital voice networks have enabled communications with such difficult-to-reach meters.
Now, increased usage of computer and telecommunications networking technologies fulfils all kinds of electric utility automation functions, including metering. Many substations are upgrading to higher-bandwidth technologies, including fibre optics, SONET, satellite, DSL, and Ethernet. Because Ethernet has become the standard for interfacing equipment to data networks, demand has increased for highend meters equipped with an Ethernet port.
BENEFITS OF ETHERNET
Ethernet provides many advantages for high-end metering applications. Probably the most significant benefit is its inherent ability to support multiple functions over one communications line. With Ethernet, we can use one communications connection for all the following applications:
- Meter reading
- Load profile retrieval
- SCADA communications
- Power quality data retrieval
- Shared meter access for interchange metering
- Customer meter access
Ethernet communication can also replace these older communications paths:
- KYZ pulse wires
- Dial-up lines
In the real world, we rarely have the option of completely abandoning old technologies in favour of new ones. For new high-end meters to be compatible with older systems, they need to support older communications methods. Many existing SCADA systems can only acquire metering information using KYZ pulses. New high-end meters must support these legacy systems.
Proactive utility engineers are specifying electronic meters with an Ethernet port to provide compatibility with future communications upgrades. KYZ pulse outputs and telephone modems offer compatibility with legacy systems.
The SEL-734 Revenue Metering System was designed with communications in mind. For compatibility with older systems, it has KYZ pulse I/O, telephone modem, EIA-485, and EIA-232 ports. For newer communications, it features an optional Ethernet port. With the SEL-734, electric utilities can solve today’s metering communications problems while also providing a path to the future.