T-68 Protecting Your Equipment through Power Quality Solutions

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Amelia York
6 years ago
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Bill Brumsickle Vice President, Engineering

2 2 Agenda What is Power Quality? Importance of Power Quality to Industrial Users Power Quality Events & Voltage Sags Voltage Sag Protection

3 3 Power Quality vs. Power Reliability Power Reliability: Continuity of electric power delivery measured by the number and duration of power outages (Zero voltage) Outages are tracked by Utilities Power Reliability can be as high as % availability Power Quality: Related to fluctuations in electricity, such as momentary interruptions, voltage sags or swells, flickering lights, transients, harmonic distortion and electrical noise Fewer such incidents indicate greater power quality Events go mostly untracked by Utilities Sag & Momentary events can take out a process as many as times per year The Grid is designed for Reliability, not Quality

Power Quality Frequency is regional Determined by HV & EHV network generators Problems are rare Voltage is area-wide Determined by MV distribution network Problems occur randomly, but with

4 Power Quality Frequency is regional Determined by HV & EHV network generators Problems are rare Voltage is area-wide Determined by MV distribution network Problems occur randomly, but with regularity Current is local Determined by facility loads Problem loads can be identified and resolved Source: DTE Energy website 4 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

System faults cause significant voltage sags (dips) Most wiring is overhead Susceptible to lightning, animals, wind-blown tree

5 Utility Power Properties of AC Grid Not always ideal sinusoidal voltages! Highly interconnected Transformer and line impedances between generators and loads Terminal voltage drops with load current System faults cause significant voltage sags (dips) Most wiring is overhead Susceptible to lightning, animals, wind-blown tree branches, etc. Source: NPR: Power Hungry: Reinventing The U.S. Electric Grid May 1, 2009 Insulation fails, equipment fails 5 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

6 6 Power Quality Problems All have physical causes

7 7 Agenda What is Power Quality? Importance of Power Quality to Industrial Users Power Quality Events & Voltage Sags Voltage Sag Protection

Electrical Equipment Designed Assuming Power Quality Operate with input ac voltage variation of 10% Possible new requirements: Operate through some voltage sags

8 Electrical Equipment Designed Assuming Power Quality Operate with input ac voltage variation of 10% Possible new requirements: Operate through some voltage sags SEMI F47 IEC Present a unity Power Factor: Current phase angle near zero Current harmonic distortion low 8 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

9 Impact of Power Quality Events Possible Agency, Utility, or Facility Requirements Power Factor correction (current phase angle) Harmonic current limits Load equipment mis-operation Voltage sags and momentary interruptions Voltage distortion (harmonics, notching) Voltage imbalance or single-phasing High-frequency voltage transients Load equipment damage High-voltage transients Current inrush following voltage sag Facility infrastructure damage High-voltage transients Current inrush following voltage sag Overheating due to current harmonics 9 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

10 Consumer is Responsible for Power Quality Utility cannot provide perfect power quality and are not required to. (e.g., Wisconsin PSC ) Customers having equipment or operations that are sensitive to such voltage fluctuations may find it necessary to install, at their own expense, power conditioning equipment or other modifications Job is to Keep the lights on. Goals Deliver maximum energy through the existing infrastructure Maintain +/-10% (on average) voltage at service entrance Minimize outages longer than 2-5 minutes Hz, when averaged over 24 hours Keep large industrial customers satisfied Minimize large customers disrupting neighbors power quality The utility is responsible for reliability, not quality of power.the customer is responsible for protecting their sensitive equipment at their own expense 10 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

11 11 Agenda What is Power Quality? Importance of Power Quality to Industrial Users Power Quality Events & Voltage Sags Voltage Sag Protection

12 Power Quality Issues Voltage sag (dip) and Momentary interruption High voltage transients (spikes) Current distortion (harmonics) Voltage distortion and voltage flicker caused by distorted current loads Voltage unbalance EPRI (Electrical Power Research Institute) Monitored 300 sites for 2+ years. 92% of all events were voltage sags under 2 seconds 4% of event interruptions from 2 seconds to 10 minutes Voltage notching Uncommon issues in the U.S. and high-tech. parks: brownout voltage swell frequency variation Poor grounding 12 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

13 13 Voltage Sag (Dip) Characterization Sag - RMS voltage reduction between 1/2 cycle - 60 sec Magnitude and Duration 1 Duration: 4 Cycles Magnitude: 60% Remaining

15 Why mostly brief sags and interruptions? 12 kv 69 kv Radial Distribution F kVA Reclosing breakers 20 MVA " C" 480 VOLTS THREE PHASE FAULT F 2 " B" " A" V = V s Z line *I F 3 Fault results in short voltage sags and interruptions for most customers, affecting up to 200 mile radius VOLTAGE BEGIN FAULT F2 OPENS VOLTAGE AT "C" AND ON F1 & F3 VOLTAGE AT "B" TIME F2 CLOSES V=0.67 p.u. V=0.40 p.u. F2 OPENS FAULT CLEARS F2 CLOSES 15 Copyright 2012 Rockwell Automation, Inc. All rights reserved.

16 Why Sag Durations are short Clearing Time in Cycles Type of Fault Typical Minimum Typical Time Delay Number of Retries Clearing Device Expulsion Fuse to 60 None Current Limiting Fuse 0.25 or less 0.25 to 6 None Electronic Recloser 3 1 to 30 0 to 4 Oil Circuit Breaker 5 1 to 60 0 to 4 SF 6 or Vacuum Breaker to 60 0 to 4 Source: IEEE Std Copyright 2012 Rockwell Automation, Inc. All rights reserved.

17 Sags at High-Tech Mfg. Sites Very few outages, still many sags! 1000 sag events from 15 Semi plants Avg. 5.4 events below CBEMA per year with transmission-level service! SEMI F47 source: International SEMATECH & EPRI, 1999

19 Impact of Voltage Sags AC Relay Voltage Sag Tolerance Curves % of Nominal Voltage Duration of Sag (milliseconds) Upper range Average Lower Range Source: IEEE Std Copyright 2012 Rockwell Automation, Inc. All rights reserved.

20 Data Corruption Source: Djokic

21 IEEE P1668 a new standard Recommended Practice for Voltage Sag and Interruption Ride-through Testing for End-use Electrical Equipment Less than 1,000 Volts A standard for the response of electrical equipment to voltage sags Expected to include: Guidance for evaluation of equipment sensitivity to voltage sags and interruptions Minimum performance criteria to specify during the purchasing process Levels of performance for acceptance of the product Voltage tolerance curves for three-phase equipment: more useful than CBEMA or ITIC

22 Effect of Voltage Sags on Equipment Most common effect is equipment drops offline PLC shutdown Open contact or relay (As little as 80% remaining voltage for 1 Cycle) A secondary effect is that

22 22 Effect of Voltage Sags on Equipment Most common effect is equipment drops offline PLC shutdown Open contact or relay (As little as 80% remaining voltage for 1 Cycle) A secondary effect is that when voltage returns, high current inrush can occur because the Softcharge circuit is bypassed RF Amplifiers, Gradient Amplifiers, and Low Voltage Power Supplies subjected to repeated hits Fail. Typical rectifier circuit diagram: Voltage SAGS can shut-down and/or damage equipment!

23 Voltage Sags Effect Equipment Example: Inrush current measured for 1kVA electronic load Normal Inrush Inrush after Sag Volts Volts Amps 0 5 10 Peak inrush 10A

23 23 Voltage Sags Effect Equipment Example: Inrush current measured for 1kVA electronic load Normal Inrush Inrush after Sag Volts Volts Amps Peak inrush 10A Soft-charge circuit is active Amps Peak inrush 50A Soft-charge circuit bypassed Note the scale change necessary to get the sagged results on the same page!

24 Only some machines shut down. Why? Fabrication or Assembly Line Layout: 480-b Machine 1 Machine 2 Machine 3 Machine 4 Machine 5 Machine a Machine power distribution and power supplies vary: L1 L2 L3 :Y Tranf. Rect. L1 N L2 N Tranf. Tranf. Controls Power Rect. Rect. Controls Power Controls Power L1 L2 L2 L3 L3 L1 Tranf. Tranf. Tranf. Rect. Rect. Rect. Controls Power Controls Power Controls Power L3 N Tranf. Rect. Controls Power

Detection of Power Quality Events Monitoring is Key to Knowing the Local Power Quality I-Sense, I-Grid Voltage Monitoring I-Sense voltage monitor device I-Grid

25 Detection of Power Quality Events Monitoring is Key to Knowing the Local Power Quality I-Sense, I-Grid Voltage Monitoring I-Sense voltage monitor device I-Grid network of monitors and database servers information and notification service & text message notification in real time Web summary, available from anywhere PDF Reports

26 I-Grid I-Sense monitors record & report PQ event data via the Internet Use Web browser to: View event details Manage accounts and monitors Generate reports and export data I-Sense Owners Internet I-Grid Servers & Database Web Utility Engineer Facility Engineer Real-time notifications Report delivery Other users

27 27 Agenda What is Power Quality? Importance of Power Quality to Industrial Users Power Quality Events & Voltage Sags Voltage Sag Protection

28 28 28 Sag Correction Solutions DySC Protection Stand-by UPS Protection CVT Protection On-Line UPS Protection

29 29 DySC and UPS Correction Capability

30 30 UPS Product Offering

thus maximizing uptime, minimizing inventory loss and reducing maintenance costs Up to 5 seconds of ride through U.S.

31 31 DySC (Dynamic Sag Corrector) DySC (pronounced Disk ) is an adaptive power supply that optimizes the remaining power during a sag by using patented inverter technology to compensate for the sag thereby maintaining an uninterrupted flow of optimal power to the load thus maximizing uptime, minimizing inventory loss and reducing maintenance costs Up to 5 seconds of ride through U.S. and International voltages available Scalable solution MiniDySC (single-phase; kva) ProDySC (3-phase; kva) MegaDySC (3-phase; kva)

32 32 DySC - Normal Operation Utility DySC Auto By-Pass Static Switch DSP Controller Load Cross- Coupling Transformer Power Conversion Rectifier Inverter Core Component DSP Controller Static Switch (99% efficient) Cross-Coupling Transformer Power Conversion Core Automatic By-Pass Activity Constantly monitors incoming power, system integrity and load Closed. Sends power directly to the load Idle Idle Idle Normal Operation - The DySC monitors power quality continuously, while the power electronics are in standby 99.99% of the time

33 33 DySC - Voltage Event Utility DySC Auto By-Pass Static Switch DSP Controller Load Cross- Coupling Transformer Power Conversion Rectifier Inverter Core Component DSP Controller Static Switch (99% efficient) Cross-Coupling Transformer Power Conversion Core Automatic By-Pass Activity Detects the leading edge of a voltage sag, immediately routing power thru the C-C Transformer and Power Conversion Core Open Pulls additional power from the grid Rectifies and inverts to recreate a true sinusoidal Output Idle DySC is On in under 2 milliseconds and recreates a true sinusoidal output

34 34 DySC Operation Normal Operation (Monitoring) Static Switch ON, Highly efficient Power electronics OFF Capacitors charged & ready No thermal cycling, long life Low maintenance Voltage Sag Correction 1-2 millisec. detection Static switch OFF Power Electronics ON, to produce corrected sinusoidal load voltage Energy from capacitors needed only for sags below 50% V = 100% V = 60% 167% 67% 167% 100% (V = 40%) patented V = 100% 100% LOAD 100% Example: voltage sag to 60%, full load We keep load voltage at 100%, so load power remains 100% Input Current rises briefly to (100% / 60%) = 167% Load energy comes from ac input, not from capacitors! Static bypass 99.99% of the time Corrects voltage by maintaining power flow (P = V x I) Most of the time the DySC is in a monitoring mode

35 35 DySC Sag Correction 330 kva MegaDySC responding to 3-phase 50% voltage sag, duration 4.5 seconds input waveforms output waveforms

36 36 DySC Interruption Correction input rms voltage 330 kva MegaDySC-ER 3-phase interruption for 250 ms (15 cycles) 90% output rms voltage

37 For More Information or Questions Power Quality at Automation Fair 2012 Essential Components (Booth 127): Protection Solutions Energy Management (Booth 541): Power Quality Monitoring Backroom Session: Hands-on DySC and I-Sense / I-Grid More information available at Booths

ECE 528 Understanding Power Quality

ECE 528 Understanding Power Quality http://www.ece.uidaho.edu/ee/power/ece528/ Paul Ortmann portmann@uidaho.edu 208-733-7972 (voice) Lecture 7 1 Today Sags and short interruptions Some Homework 2 pointers