DFR Executive Summary
The DFR equipment is an improved sub-station oscillograph for the collection of transmission and generation substation voltage and current at high sample rates and long duration, suitable for evaluating the system dynamic performance at the same level used in EMTP type simulations.
The DFR measures the system voltages and currents for up to 32 channels typically at 120 samples per cycle, which may be time-synchronized with other IT Inc. DFR systems. Twenty four (24) contact closure digital inputs are provided for tracking breaker position during the course of a system event.
Eight (8) channels of digital output are provided for driving auxiliary relays or as input to plant distributed control systems (DCS) or SCADA.
The DFR provides event triggering based on relay targets, and based on conventional triggers for over and under voltage and current, and rate-of-change of response.
The DFR trigger points are established and time-stamped to one-micro-second accuracy using a satellite synchronized clock. This feature allows the collection of multiple DFR data for assembly at a single location for viewing and analysis with the same time context for all of the data. This collection may be done in the DFR binary file system or by use of the comtrade conversion facility. In the DFR binary file system multiple DFR data is easily assembled using the Ethernet equipment.
The DFR input voltage and current signals have galvanic isolation and are assembled in four eight-channel groups. Each group typically is configured to provide three phase voltage and current, and neutral current. The signal conditioning however can be user strapped for either voltage or current measurements.
The DFR is user configured for unit identification, channel type, name, position, and signal calibration.
The DFR local human interface is provided through a Windows 2000 computer equipped for ethernet communication for enterprise-wide data access.
Available on request