Siemens UL1066, UL 489 specifications Metering Function Plus, General

Communication-capable Circuit Breakers

WL Circuit Breaker

Metering Function Plus

The integrated metering function can be used with all trip units with a CubicleBUS connection. It not only extends the range of protection functions of the trip unit but also provides additional warnings and diagnostic options. With its comprehensive range of measured values, the integrated WL Circuit Breaker metering function is an excellent alternative to external multi- function metering devices.

General

In addition to the current values supplied by the trip unit, the metering function provides the measured values in the power distribution system required for Power Management (voltage, power, etc.). With its extended protection function (e.g. undervoltage), the metering function also provides further options for monitoring and protecting the power distribution system.

The option of generating warnings if setpoints are exceeded, speeds up response to system alerts. As a result, the metering function can significantly increase system up-time.

The metering function module is installed on the back of the trip unit (ETU), as shown in Fig. 2-4. The trip unit and metering function module exchange all current data via a high- speed synchronous interface. The metering function module provides all the connected modules (e.g. the COM16 module or BDA) with the parameters for the protective relay functions, the setpoints, measured value settings, and the measured values via the CubicleBUS, so that they can be processed further. Using the two CubicleBUS connections, the metering function module is connected to the trip unit and either the BSS or directly to X7.

The metering function can be implemented in all circuit breakers with ETU745, ETU755, ETU748 and ETU776. If the Metering Function PLUS module is ordered with the assembled circuit breaker, it will already be installed and ready for operation. The metering function can be retrofitted at any time if the circuit breaker is equipped with one of the trip units listed above. It is simply screwed onto the trip unit and the CubicleBUS lines are snapped in.

Note: If installed by the customer, the metering function is not calibrated with the trip unit; therefore, the accuracy of the specifications in Table 2-7 cannot be guaranteed.

The Metering Function Plus is located on the back of the trip unit. When ordered as Figure part of an assembled breaker catalog number, it is already installed and ready for

2-4operation.

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WL MODBUS Communication and Electronic Accessories • January 2005