Date Code 20081022 Instruction Manual SEL-787 Relay
Section 9
Analyzing Events
Instructi on Manual
Overview
The SEL-787 Transformer Protection Relay provides several tools (listed
below) to analyze the cause of relay operations. Use these tools to help
diagnose the cause of the relay operation and more quickly restore the
protected equipment to service.
➤ Event Reporting
➢ Event Summary Reports
➢ Event History Reports
➢ Event Reports
➤ Sequential Events Recorder Report
➢ Resolution: 1 ms
➢ Accuracy: ±1/4 cycle
All reports are stored in nonvolatile memory, ensuring that a loss of power to
the SEL-787 will not result in lost data.
Event Reporting
Analyze events with the following event reporting functions:
➤ Event Summaries—Enable automatic messaging to allow the
relay to send event summaries out a serial port when port
setting AUTO := Y. A summary provides a quick overview of
an event. The summaries may also be retrieved by using the
SUMMARY command.
➤ Event History—The relay keeps an index of stored nonvolatile
event reports. Use the HISTORY command to obtain this
index. The index includes some of the event summary
information so that the appropriate event report can be
identified and retrieved.
➤ Event Reports—These detailed reports are stored in nonvolatile
memory for later retrieval and detailed analysis.
Each time an event occurs, a new summary, history record, and report are
created. Event report information includes:
➤ Date and time of the event
➤ Individual sample analog inputs (currents and voltages)
➤ Digital states of selected Relay Word bits (listed in Table J.1)
➤ Event summary, including the front-panel target states at the
time of tripping and fault type
➤ Group, Logic, Global, and Report settings (that were in service
when the event was recorded)
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