Power Quality Metering and Case Studies Presented by

Mike Dolinac Wisconsin Public Power, Inc. Presented on April 10, 2006 at the 2006 Engineering & Operations Technical Conference in Sacramento, California

UTILITY METERING SERVICES • Two basic forms of metering • Power - kW, kWh, kVA and Power Factor • Power Quality - voltage fluctuations, harmonics... • 12 PM 3000 Meters (Outram Research) for ESR’s • 3 Metrosonic/AVO PA9 Meters • 2 Reliable Power Meter (RPM)/Fluke

Power Measurement Examples • Check kVA load on a transformer • Check current (AMPS) on a panel • Check Power Factor • 15 minute kW demand intervals • Energy use and energy cost of of equipment • How much does it cost to run the air compressor? • Old vs. new equipment

Power Quality Measurements • High or low voltage problems • Blinking lights • Equipment failure/problems • Computer/control problems • Tripped breakers or blown fuses • Harmonics (conductor/transformer overheating) • Surge or sag problems

Case History #1 - Sensitive Equipment • A customer had sophisticated electronic equipment that kept “tripping out” causing down time and loss of $$$$$. • The customer contacted the local utility to help solve the problem. • Utility staff and I connected PQ meters to the input of the equipment and told the customers to mark down the times when they had problems.

Sensitive Equipment Case Study

Solution • Problem caused by capacitor bank 15 miles away! • Customers added chokes/filters at input. • The “key” was the customer marking down the times of the problem...

Case History #2 - Blinking Lights • An industrial customer calls and says his lights are blinking and he’s having computer problems. • The customer has many large single phase welders throughout the building. • Utility staff and I connect a meter at the service entrance.

PSC Requirement

CBEMA Curve

Fast Sampling Rate

Blinking Lights Solution • Blinking lights caused by welders. • The utility, by PSC rules, did not have to help. • The utility installed larger transformers and conductors to the building. • Customer upgraded the service entrance and installed larger conductors for the welders. • Customer may need 2nd service for welders or?

Case History #3 - A/C Motor Failure • A customer just installed a new air conditioning unit. • They had burned up 3 motors when they called. • A/C contractor said it was “Bad Utility Power” and refused to warranty any more motors. • The customers staff was stuck in the middle and just wanted the A/C to work. • We connected a meter right to the unit.

A/C Unit Motor Failure

A/C Motor Solution • Compressor motor was starting every 3 minutes 24 hours a day, 7 days a week. • Most motors are rated to start up to 6 times per hr. • The thermostat for the unit was tied into a computerized energy management system. • The was no “dead-band” or leeway for the thermostat. Usually, it’s one or two degrees. • Contractor adjusted the thermostat settings and the problem was solved.

Case History #4 - Electronic Scale • A customer was having trouble with it’s new electronic scale. • The panel it was fed from also had some A/C units on it. • Lights were blinking like a 1970’s disco. • We connected the meter at the utility transformer that fed the panel.

PSC Requirement

Electronic Scale Solution • The transformer was overloaded. • It was replaced with a larger unit and the voltage rose to about 121 volts at the panel.

Case History #5 - Breaker Tripping • Small industrial customer has a 1200 amp main. • The breaker trips once a month for past 3 yrs…… • They simply walk over to the breaker and flip it back on without shutting off any equipment. • The last time someone threw the breaker back on a baseball sized chunk of switch gear flew out the side of the panel. • That’s when they called us….

1200 AMP Main

Breaker Solution • The 1200 amp main service was simply overloaded. The average load was about 1250 to 1400 amps. “Spikes” were caused by momentary motor starts. • The customer will upgrade to at least a 2000 amp service. (Sized from average load).

Checking kW Demand • Customers are billed for the highest 15 minute average kW demand during the month • It’s to the customer’s advantage to have a nice “flat” demand • Try to avoid 15 minute“spikes”…. • Motor starts DO NOT cause your bill to be high • It’s just like “leave the lights on” it’s cheaper...

kW Demand - 15 Minute Average

Case History #6 - The Hospital • A hospital was having problems with equipment failure in the intensive care unit. • They said most failures occurred after an outage. • The equipment supplier blamed the failures on “Power Surges” coming from the local utility. • I connected the meter to an old lady’s pacemaker in intensive care.

Guess what this is?

Hospital Solution • The generator had a manual governor to regulate it’s speed and voltage. • Peak voltage was about 142 volts and the average output was about 132 volts. • The hospital installed a new electronic voltage regulator on the unit and the problems went away. • Unfortunately, the old lady died when I accidentally grounded her pacemaker to a stainless steel bed pan.

Case History #7 - Harmonics? • I receive a call from one of our utilities saying a customer has a remote control light from Radio Shack that doesn’t work. • The customer thinks it’s harmonics? • I can’t wait to see this guy….. • I arrive a $1,000,000 house on the lake. • The owner is sitting in the dark.

Harmonic’s cont…. • The guy has wired his whole house with remote control switches from Radio Shack. They use high frequency power line carrier signals. • Every light fixture, TV’s, stereo, A/C, coffee maker, toaster, outdoor lighting, etc….. • He has one fluorescent fixture in the laundry room that works. Other than that he’s sitting alone in the dark. He says he thinks he knows what the problem is… • I think he’s nut’s but I don’t say anything.

Harmonic’s cont. • He takes me outside. Now I start to worry…. • I swear I can hear the theme song from “Deliverence” coming from somewhere…. • He points to a utility pole with a small transformer at the top of it. • Attached to the bottom of the transformer is the biggest wasp nest I ever saw. • He points and says, “Harmonic’s”…...

Harmonic’s cont... • He says the “humming” from the wasp nest is interfering with the 60 hertz from the utility. • I figure I’m either on Candid Camera or an episode from the Twilight Zone. • We go back inside and I hook up the meter at his service entrance with the aid of a flashlight. • Hmmm, I do see something? • I take my life in my hands and ask him to shut off the fluorescent light.

Harmonic’s Solution • I asked him to try his remote control now. • It worked! • The high frequency noise and or harmonics from the fluorescent light ballast had been interfering with remote control signal. • As I leave, he waves as he’s throwing out the fluorescent fixture from the laundry room.

Talking Refrigerator • A residential customer called and told us her refrigerator told her she had bad power • I brought along a power quality meter and a straight jacket • When we got there, it was your typical half million dollar house • Here’s a profile of the house’s energy use 4/3/2006

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10.00

Ice melter for observatory

9.00 8.00

Basketball court lights

Wine cellar coolers

7.00 6.00 5.00 Real Power (kW)

4.00 3.00 2.00 1.00 12/08/03 13:51:54

12/11/03

12/12/03 (mm/dd/yy)

12/13/03

Average of kW on Ch 7

12/15/03 13:51:54

Talking Refrigerator Cont… • The lady of the house said her refrigerator told her she had low voltage • It was a fancy stainless steel refrigerator with a LCD display and it did talk • It told me there was a voltage sag at 8:14 am and that they were out of milk 4/3/2006

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Talking Refrigerator Cont… • We connected the PQ meter to the service entrance • Here’s what we found…

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1 2 0 .0

1 0 0 .0

8 0 .0

6 0 .0 AC Voltage (Vac)

4 0 .0

2 0 .0

0 .0 1 2 /0 8 /0 3 1 3 :5 1 :5 4

1 2 /1 1 /0 3

1 2 /1 2 /0 3 ( m m /d d /y y ) Vac on Ch 1 Vac on Ch 2

1 2 /1 3 /0 3

1 2 /1 5 /0 3 1 3 :5 1 :5 4

1 3 0 .0 1 2 8 .0 1 2 6 .0 1 2 4 .0 1 2 2 .0 1 2 0 .0 1 1 8 .0 AC Voltage (Vac)

1 1 6 .0 1 1 4 .0 1 1 2 .0 1 1 0 .0 1 2 /0 8 /0 3 1 3 :5 1 :5 4

1 2 /1 1 /0 3

1 2 /1 2 /0 3 ( m m /d d /y y ) Vac on Ch 1 Vac on Ch 2

1 2 /1 3 /0 3

1 2 /1 5 /0 3 1 3 :5 1 :5 4

1 4 0 .0

1 2 0 .0

1 0 0 .0

8 0 .0

6 0 .0 AC Voltage (Vac)

4 0 .0

2 0 .0

0 .0 0 8 :1 4 :1 2 1 2 /1 2 /0 3

1 4 :2 0

1 4 :2 5 (m m :ss) Vac on Ch 1 Vac on Ch 2

1 4 :3 0

0 8 :1 4 :3 9 1 2 /1 2 /0 3

Conclusion… • The refrigerator did detect a “voltage sag”.. • But the refrigerator did not actually talk… • The toaster was a ventriloquist….

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Power Quality Meters • Here’s what we use at WPPI

Reliable Power Meter (FLUKE)

AVO/Metrosonics PA-9

PM3000 Outram Research

NEXUS 1270 Electro Ind (GE)