SCADA Alarming Practices A Quick Overview of Some of AECI’s SCADA Alarming Practices

Alarm Philosophy Background

requiring a response. (ISA 18.2) Should an alarm exist? An audible and/or visible means of indicating to the operator an abnormal condition requiring a response. (ISA 18.2)

How long before it happens? Rationalization How Severe? Severity Priority High Medium Low Consequence How long before it happens? Time to Respond

Severity of Consequence + Time = Priority Minor Consequence Major Consequence Severe Consequence ≈ 30 minutes Low Medium ≈ 10 minutes < 3 minutes High

In the real world… High Medium Low None Priority Color Examples Red Any alarms involving human safety (Require individual acknowledgement) Fire Alarms Danger to Personnel Rare occurrences MVA Limit Exceeded Medium Orange Exception for CBs, CSW, MOS, Disconnect Any change of state Yellow MVA Warning Voltage Limit Exceeded Tie shift   Low White Voltage Warning LTC Reasonability exceeded Analog Return to Normal Temporary holding for unrationalized alarms This makes them easy to find and rationalize later.  Station Alarms Green Default system color for issued control commands None Light Blue External, off-system events. Do not require acknowledgement. Historical info only. External CB operations External MVA and KV Limits Gray Deleted "Log Only" events. Never require a response. Appear only when viewed from All/Summary views. System Event log In the real world…

MVA Alarms – Line Loading Event Class Message / Description Deadband Sound MVA Limit 2 Exceeded Limit   Yes MVA Limit 1 Near Limit – 90% Return to Limit 1 Improved to Near Limit 1% and 20s MVA RTN Normal MVA Data Reasonability Data Unreasonable 12s

MVA - Dynamic Limits Temperature data from a weather service G&Ts associated with a region to determine location temperature Substation owner associated with lines and transformers Calculate rating based on most limiting element at the temperature for that region FAC 008 Conductor ratings Map temperature adjusted ratings to SCADA points on EMS.

Voltage Alarms Event Class Message / Description Deadband Sound KV Limit 2 Exceeded High/Low Limit   Yes KV Limit 1 Near High/Low Limit Return to Limit 1 Improved to Near Limit 1% and 20s KV RTN Normal KV Data Reasonability Data Unreasonable 12s

Voltage Limits 74.5 - 108% 149 - 108% 173.9 - 108% 249 - 108% High Exceeded Limit 2 74.5 - 108% 149 - 108% 173.9 - 108% 249 - 108% 372.6 - 108% 540 - 108% High Warning Limit 1 72.5 - 105% 147 - 106.5% 171.5 - 106.5% 245 - 106.5% 367.4 - 106.5% 532.5 - 106.5% Nominal Voltage 69 KV 138 KV 161 KV 230 KV 345 KV 500 KV Low Warning Limit 1 65.5 - 95% 131.1- 95% 153- 95% 223.1 - 97% 334.7 - 97% 485 - 97% Low Exceeded Limit 2 62.1 - 90% 124.2 - 90% 144.9 - 90% 218.5 - 95% 327.8 - 95% 475 - 95%

CB, CSW, MOS, Disconnects Event Class Message / Description Deadband Sound Change of State Changed State   Yes Multiple Operations Return to Normal Returned to Normal Control Failed

Fin