8 - Power Quality Events and Disturbances

Power Quality Events & Disturbances

• Events are short-term unexpected occurrences, denoted by magnitude, duration, and direction. Examples include voltage sags, voltage swells, interruptions, over/under voltage.
• Disturbances are long-term and logged periodically. Examples include voltage unbalance, current unbalance, voltage harmonics, current harmonics, frequency variation, and flicker.

Summary of Power Quality Events

• According to IEEE 1159:
  • Voltage varies by > 1% of nominal voltage for less than 1 second
  • Voltage sags: Duration between 0.5 and 5 seconds, voltage dips less than 90% for 0.5 seconds
  • Voltage swells: 110% to 120% of voltage
  • Interruptions: > 1 second
  • Over voltage: Greater than 110%
  • Under voltage: Less than 90%

Summary of Associated Waveforms

• Power quality events are detected and stored as waveforms
• Waveforms are categorized as:
  • Disturbances (Typically, start, middle, and end)
  • Normal
  • Long duration events (Disturbance, end, middle, normal)
  • Voltage and current waveforms per channel

Power Quality in PME (Power Management Expert)

• View power quality data in PME Alarm Viewer and View Library
• When PME is used with a PowerLogic device, it allows for monitoring of power quality

PowerLogic Devices

• Advanced PowerLogic devices capture power quality information:
  • Magnitude (as a percentage of nominal voltage)
  • Duration (in seconds)
  • Waveforms (per channel)
  • Disturbance direction (upstream or downstream)
• Basic devices do not have PQ detection or waveform capture capabilities.

Burst Data – ION 9000

• Pre- and post-event data logged during an Alarm Instance
• Devices store a continuous buffer of data logs
• Burst data can be viewed in PME Alarm Viewer
• Incident Timeline Analysis: Used to analyze power quality events over time

High Speed Transient Capture – ION 9000T

• High-speed transient capture (HSTC) feature is available only on ION9000T
• High-speed transient monitoring at 10 MHz sampling with up to 10 kV peak recording
• ION9000T can be used in medium voltage applications with high-bandwidth voltage transformers
• HSTC is not supported on serial or gateway connection

Disturbance Direction Detection (DDD)

• Patented PowerLogic feature: Determines if a PQ event occurred upstream (utility) or downstream (facility).
• Enabled automatically when PQ detection is enabled.
• Viewed as part of PME Alarm Viewer and can be added to a custom user diagram

Configuration Procedure

• PQ monitoring, alarming, and analysis function properly when the monitoring devices are configured to capture power quality events and disturbances
• Configure Power Quality Settings:
  • System Type, CT and PT ratios
  • Clock and time synchronization
  • Nominal voltage
  • Nominal current
  • Nominal frequency
  • Standards Compliance (e.g., EN50160 or IEC 61000-4-30)

Static Nominal Voltage

• Must be non-zero to enable PQ detection.
• Set to the normal operating line voltage of the electrical system
• Use "line-to-neutral" value for WYE systems and "line-to-line" value for Delta systems

Sag and Swell Waveform Captures – ION9000T

• Configure waveform captures:
  • Open Setup Assistant using ION Setup
  • Set the maximum number of records
  • Enable Burst Data logging
  • Set the maximum number of waveforms to record
  • Generate COMTRADE format waveform data

Transient Waveform Capture – ION9000T

• Configure waveform captures:
  • Open Setup Assistant using ION Setup
  • Set the maximum number of records for transient data log
  • Set the maximum number of waveforms
  • Generate COMTRADE format waveform data

High Speed Transient Capture – ION9000T

• Configure waveform captures:
  • Open Setup Assistant using ION Setup
  • Set the maximum number of records
  • Provide Log depth for HSTC waveform

Recap

• Power quality is a set of limits that define how equipment in an electrical system operates correctly
• Advanced PowerLogic devices (PM8000 and higher) provide power quality monitoring, alarming, and analysis capabilities.