demonstration of year 1 prototypes and testing methods

8/3/2019 Demonstration of Year 1 Prototypes and Testing Methods

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ELECTRIC POWER INDUSTRY APPLICATIONS OF MEMS

SECURE Projectsponsored at UC Berkeley by the

California Energy Commission

Richard M. White, EECS Dept.

Sensor Team

15 August 2008

Berkeley Sensor &Actuator Center


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AC RMS VOLTAGE

120 660 V 4 69 KV 115 KV and up

Residential/Commercial Distribution Systems Transmission Systems


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AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up


Wireless passive proximity measurement of AC current, voltage, phase, power

BASIS:MEMS


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AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up


Wireless passive proximity measurement of voltage, current, phase, power

Demand Response

Fault detection

Metering

System monitoring,

control

System monitoring,

controlAPPLICATIONS


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System monitoring,

control


AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up



Demand Response

Fault detection

Metering

System monitoring,

control

Energy scavenging from energized circuit via sensor + efficient rectifier


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System monitoring,

control


AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up



Demand Response

Fault detection

Metering

System monitoring,

control


Conductor temperature measurement

Line sag measurement

Vegetation growth detection


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System monitoring,

control


AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up



Demand Response

Fault detection

Metering

System monitoring,

control





Assessment of U/G

cable aging


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System monitoring,

control


AC RMS VOLTAGE

120 240 V 4 69 KV 115 KV and up



Demand Response

Fault detection

Metering

System monitoring,

control





Assessment of U/G

cable aging

Remote (non-MEMS) field-based voltagemeasurement


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Specifics

Assessment of U/G

cable aging

Staffing: Giovanni Gonzalez, Michael Seidel, Bo Zhang; Igor Paprotny (Post-Doc with

MEMS experience joining Sept. 1)

Off-Site:

3 grad students and Prof. White visited and did experiments at Steven Boggs lab (U.

Conn.) in May, 2008.

Prof. White attended EPRI-NEETRAC meeting in Chicago in June 2008 (NEETRAC offerfrom Nigel Hampton to test our sensors there).

Review of Five Proposed Methods for Studying In-Service

Cables (from our Workshop held 25-26 February 2008)


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Five Methods for Studying In-Service Cables

1. Measure, with small probe, dependence on instantaneous appliedvoltage of permittivity of cable insulator, and determine nonlinearity

2. Probe electric fields or potentials just outside cable to infer insulator

permittivity, and determine nonlinearity as applied voltage changes


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COMSOL simulation (by Piero Marcolongo, Prof. Evans student) of

electric potential shows substantial AC potential exists just outside

jacket between adjacent concentric neutrals, and that its amplitude is

affected by permittivity of insulator there. Will attempt with a properly

shielded microsensor to detect this potential to measure insulator

properties at different times in applied voltage cycle looking for

nonlinearity.


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3. At cable end, measure currents in individual concentric neutrals to

identify open concentric neutrals (no current) and asymmetry (detectpossible degradation near concentric neutral wire)


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AC current

sensor output

magnet

piezo cantilever

MEMS-based version of

passive proximity AC current

sensor. Permanent magnetcouples to AC magnetic field

to drive piezoelectric-coated

cantilever and produce proportional

AC voltage output


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1. Measure, with small probe, dependence on instantaneous applied

voltage of permittivity of cable insulator, and determine nonlinearity





4. Using pairs of concentric neutral wires as transmission line, from

reflections and/or loss infer insulator permittivity and loss as function of

instantaneous applied voltage to determine nonlinearity


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High-voltage pulsed source (electrostatic discharge tester, gift of

Kikusui Corp.) might launch usable pulse through jacketnon-destructively onto a concentric neutral wire transmission line.

Source voltages adjustable from -30 kV to +30 kV, central spike

1 ns duration, pulse shoulder to 60 ns.


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4. Using pairs of concentric neutral wires as transmission line, from

reflections and/or loss infer insulator permittivity and loss as function of

instantaneous applied voltage to determine nonlinearity

5. Using surface guided wave, from propagation velocity, reflectionsand loss as function of instantaneous applied voltage, infer insulator

permittivity, loss and nonlinearity


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RF SOURCE

Surface wave RF transmission line with waves guided by

dielectric coated conductor. Low loss at high frequencies

(Goubau line). Conventional insulated distribution cablewould guide it. Its propagation characteristics might be

affected by dielectric nonuniformities in the cable insulator.


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Specifics

Assessment of U/G

cable aging

1. Interdigital sensor to measure dependence of insulator permittivity on electric field:

a. Simulation of test device

b. Designed/submitted photomask for Microlab fabrication TEST with solid

dielectric; TEST with short length of cable; PLAN TEST with energizedcable

2. Electric field sticking out of cable

a. Materials Team did simulation showing detectable external field:

can this be detected and is that useful?

b. Design/build an electrostatic sensor for use at power frequency

(we have an inexpensive commercial E-field sensor but it works well

only at very high frequencies) TEST with short length of cable

at 5 kV (Material Team lab)

(continued)

Where do we stand on these proposed techniques?


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4. RF transmission lines that are integral to cable concentric neutral wires

a. Tested earlier using 8-foot cable measuring transmission/loss

b. Analyzed two-wire line large loss so use strong external drive

c. Two sources now in house: spark coil (7 kV?); ESD tester (30 kV,

few ns pulse length) TEST with existing cable (8-foot)

HELP! WE NEED MORE NEW OR OLD CABLE ~ 100 FEET?

Specifics

Assessment of U/G

cable aging

(continued)

3. Instrumentation for measuring uniformity of concentric neutral currents:

a. Current detection test at Prof. Boggs lab with short length of cable

b. PG&E gift of current transformer from San Ramon lab for current source

c. Holder for current sensors designed/built

d. Obtained/mounting very sensitive 2-axis commercial magnetometer chip to

TEST on short length of cable, along with Berkeley current sensor(piezoelectric-coated cantilever with magnet)

e. SIMULATE external magnetic fields for different drive conditions (noise

issue)


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SUMMARY

1. Many possible applications for wireless MEMS sensors

2. Progress on in-service U/G distribution cable assessment

a. Simulation/design/start of fabrication ofinterdigital sensorto

measure voltage dependence of insulator permittivity (nonlinear?)

b. Considering design of sensor to detect electric field leakage from

cable to compare with simulation

c. Instrumentation/preliminary test of ability to measure CN currentsd. Excitation of integral RF transmission lines to test cable irregularities

begun

3. Consideration of voltage, current, power sensing for distribution

voltages and higher

demonstration of year 1 prototypes and testing methods

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