Analysis of Recording Elements

Author: Alexander Apostolov, Damien Tholomier

Summary

Recording of different types of power system events is extremely important for the successful analysis of wide are disturbances and the verification of  the system models used in the design of protection and emergency control systems. The paper discusses the recording elements in different types of multifunctional Intelligent Electronic Devices. The effect of analog and digital filtering, sampling rate, recording and storage methods on the quality of the records is analyzed in the paper. 

Even that the recording of analog values is the primary function of disturbance recording devices, the capture of change of state of monitored binary inputs is also important for the analysis of the operation of substation primary or secondary equipment. Methods for detection and their effect on the accuracy of time-stamping are presented in the paper.
IEC 61850 is the new international standard for communications in substations. It defines station and process bus communications between the different components of the system:
The paper describes the different components of a system for recording of wide area disturbances in substation automation systems with IEC 61850 based communications. The distribution of functions between the individual devices is analyzed from the point of view of system architecture and reliability requirements.
Process interface devices (Merging Units) are described as forming the data acquisition layer in the distributed recording system. They communicate over a 100 Mb/sec Ethernet with a central computer that records the system transient event with 256 samples/cycle.
The paper describes the architecture of the system, recording triggering criteria and the system performance requirements.
Accurate time synchronization is a key requirement for any distributed recording system. The accuracy of time synchronization is another critical attribute of the recording IED. The paper discusses different methods for time-synchronization used today, as well as the emerging IEEE 1588 standard.

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