LEM Unveils Wireless Electrical Sub-Metering Components

LEM S.A. announced its Wi-LEM (Wireless Local Energy Meter) family of components, which allow electricity consumption to be monitored and reduced. Its use of wireless communication is meant to enable a significant reduction of the time, cost and disruption involved in deploying sub-metering installations, ultimately leading to financial savings.

Electrical sub-metering provides powerful information about how, where, and when electrical energy is used. This enables energy managers to make important decisions that can reduce electrical energy consumption and costs, and improve efficiency. Electrical sub-metering can be used effectively by a wide variety of energy users in both industrial and commercial settings.

The Wi-LEM's small footprint and split-core transducer simplifies the installation process, leading to less expensive and shortened installation periods. Additionally, the compact sized split-core transducers can easily be installed inside the limited free space of existing cabinets. Wireless communication over 2.4 GHz enables impressive flexibility, as the components may be installed anywhere in the cabinet. LEM leverages the Zigbee 802.15.4 standard for its wireless automated monitoring network. This IEEE-defined standard allows for a high number of nodes, is in line with the small size of the components, and works on an RF frequency range of 2.4 GHz.

The Wi-LEM family consists of an Energy Meter Node (an assembly of 1 to 3 current transducers with a signal processing module) that can be deployed to measure energy consumption at any point in the power cabinet and transmit the data; a Mesh Node (a repeater linking various Nodes) that enables wireless communication throughout a large installation; and a Mesh Gate (a gateway managing the mesh network) which provides data through serial interface to a PC.

By measuring active, reactive and apparent energy plus maximum current and minimum voltage, Energy Meter Nodes provide much more information than a simple sub-meter. A variety of Energy Meter Nodes – all with accuracy certified to IEC 62053 Active Energy Class 1 and Reactive Energy Class 3 – are available for 120 and 240Vac voltages and can be configured for nominal currents from 5 to 100A. Energy Meter Nodes take measurements at 5 to 30 minute intervals and transmit the results over the 2.4 GHz ISM band. The technologies make installation and commissioning very easy.

Mesh Nodes act as repeaters, and can be added to the network without any need for additional configuration or programming. The Mesh Gate is a stand-alone wireless network management gateway that connects the transducer network with a PC using a serial interfaces RS-232 or RS-485 with a MODBUS RTU protocol. Each Mesh Gate allows monitoring of up to 240 Energy Meter Nodes.