PowerFactory Monitor

Functional Overview

The DIgSILENT PowerFactory Monitor is an integrated, multifunctional data acquisition system that covers recording, monitoring and analysis of signals in all relevant time frames. It is especially designed to cover all needs of Transmission, Distribution and Generation on all voltage levels. Flexible hardware and software components allow for the configuration of portable systems, stand-alone cabinet mounted installations as well as LAN based multiple units, multiple location systems being coordinated and supervised via Master Stations

Key functions which could be operated simultaneously are:

• Fast and slow fundamental frequency signals recording (triggered and continuous)
• Triggered instantaneous value recording
• Phasor measurements
• Event recording and power quality monitoring
• Condition supervision and monitoring

Any quantity deviating from normal conditions is recorded and analysed. In addition, on-line analysis of signals is provided featuring the detection of inherent problems like system and control oscillations, deviations from connection conditions or power quality aspects. The PowerFactory Monitor is a stand-alone system including all necessary hardware and software functions for signal conditioning, signal conversion, data storage and processing, calculation and documentation. In addition, remote access is possible via modem, TCPI/IP networks, WWW and special SCADA interface techniques. Several monitoring systems can be synchronized to 1ms using GPS clock for precise parallel sampling, e.g. a basic requirement for system wide area phasor measurements.

Technical Overview

Hardware Configuration

The PowerFactory Monitor is based on a Control and Monitoring Unit (CMU) which can be equipped with up to 4 Signal Units (SU) supporting in total up to 128 analogue channels (32 channels for the portable system) and 64 event inputs being processed and analysed with a maximum scan rate of 15.36 kHz per channel at a 16 Bit resolution. Each Signal Unit can accommodate different types of signal conditioning devices featuring highest flexibility for direct connection of current- and voltage transformers but also low level AC/DC-voltage and -current signals. Various PowerFactory Monitoring (PFM) Systems can communicate with the PowerFactory Master Station for supervising the status of the PFM network, for collecting essential recorded information or for building a two level monitoring structure for selective and most vital display and analysis functions.

Multi-time Frame Recording

Based on high speed signal data acquisition the PowerFactory Monitor generates a number of different data streams that allow for fault and disturbance recording, event recording, power system performance supervision, power quality recording as well as special on-line signal generation such as real time phasors and frequency monitoring.

Power System Performance Supervision

Fundamental frequency and phasor quantities (RMS) are determined on basis of high precision soft transducers with scan rates of up to 2-4 samples per cycle being time tagged with a 1μs resolution. High-speed recording of large amount of quantities is typically triggered via threshold criteria on primary signals or on basis of any criteria being derived from flexible equations or analysis functions incl. oscillation detection. Intelligent re-trigger functions are provided to guarantee capturing of disturbance sequences which may occur during catastrophic and extended network upset conditions. Triggering is reported to the Master Station initiating automatic upload of data should this be requested by the overall monitoring setup.

Real Time Phasors

Based on the flexible setup of the PowerFactory Monitor, frame and high level slot function definitions, various specific measuring devices can be configured. A typical application of such flexibility would be the real time phasor measurement where various phasor quantities are derived from local information, stored, analysed or passed on to remote systems for coordinated stability evaluation.

Power Quality Recording

Capturing of voltage sags and high voltage conditions along with the continuous monitoring and recording of harmonic distortion, phase unbalance and other quantities of interest, continuous power quality monitoring is provided. Any recording such as captured voltage sags or daily 24 hours power quality records can be kept locally at the PFM or may be transferred automatically to the Master Station for centralized storage and review.

Automatic Analysis

On the basis of standard PowerFactory DPL scripts, the PowerFactory Monitor features the automatic analysis of monitoring data streams as well as recorded, event triggered data sequences. This will allow a pre-processing of the many recordings to determine its severity and relevance for further expert analysis. A typical standard feature of the automatic event and monitoring analysis would be the performance of automated printing of all recorded data sequences.