IEEE Moisture Standard Chicago 0511ewh.ieee.org/cmte/substations/sck0/wgk8/Chicago 2011 Presentations... · Operating Principle ... 6SF Hygrometer, high precision H 2O detection ...

Pressure and Temperature Measurement

IEEE Moisture Measurement Standard

2011 PM-SF61

Chicago, IL

Wednesday, May 18, 2011

Ron Hoffman & Peter Pilzecker

Pressure and Temperature Measurement

Agenda

1. Overview

� Description

� Operating Principle

� Typical test setup (including diagram)

� Typical test procedure

3. SF6 Gas Used During Measurement

� Gas Flow Rate

� Amount of Gas per sample

� Method of gas capture

� Concern for decomposed SF6 products (gases & particulates)

2011 PM-SF6

� Digital Storage

2. Working Parameters

� Operating temperature range

� Maximum operating pressure

� Accuracy (note 1st measurement)

� Frequency of calibration

2

� Use of filters?

4. Conclusion

� Pros/Cons

� Instrument selection considerations

Pressure and Temperature Measurement

1. Overview

� Description & Operating Principle

� SF6 Breaker Analyzer 3 in 1 interpreted

analysis (Humidity, SF6 %, SO2), humidity

based on a capacitive Polymer sensor

� SF6 Humiditor, humidity detection based on a

capacitive Polymer sensor

2011 PM-SF6

� SF6 Hygrometer, high precision H2O detection

based on chilled mirror technology

� SF6 Recovery Kit (collection bag for sampled

SF6 gas with optional compressor)

3

Pressure and Temperature Measurement

1. Overview

Chilled mirror(Physical measuring principle)

In a chilled mirror humidity measuring device, the SF6-gas

is routed alongside a mirror which is cooled down to the

dewpoint temperature of the SF6-gas by a peltier heat

pump. If the dewpoint temperature has been reached

Electronic dewpoint measuring device

(capacitive polymer sensor)

� Based on the absorption of water molecules in a substance

acting as dielectric in a capacitor (ceramic, Aluminium-Oxide or

Polymer).

Description & Operating Principle:

2011 PM-SF64

(complying with the humidity content of the SF6), a

condensation / ice layer (depending on the temperature

range) on the mirror will be detected.

� Changing of the capacity relative to the humidity content.

� Conversion of the capacity change in a humidity value using the

electronic evaluation.

SF6-Hygrometer

Accuracy: ±0.1 °C DP

SF6-Humiditor /SF6-Breaker-Anaylser

Accuracy: ±2 °C DP (for +20…-40°C)±4 °C DP (for < -40°C)

Pressure and Temperature Measurement

1. Overview

� Typical test setup Humidity-Module

2011 PM-SF65

It is also possible to connect the recovery-bag

directly to a service cart.

Pressure and Temperature Measurement

1. Overview

� Typical test procedure

� The instrument is connected to the tank

� The line is purged

� Test begins

� Testing completed in approx. 7 min

(The integrated Skip-Function allows to skip the

2011 PM-SF6

(The integrated Skip-Function allows to skip the

remaining time of the measurement and save the

data if the adjusted level for the SF6-Quality has

been reached in order to save time and SF6.)

� Results interpreted (GA10) according to international

standards or standards of the user

� SF6 gas reclaimed using Recovery Bag

6

Pressure and Temperature Measurement

1. Overview

� Typical test procedure

� Results recorded (GA10) for future use and analysis

(SF6 Reviewer software included)

2011 PM-SF67

Trending allows early fault detectionSF6-Reviewer –Reporting software

Pressure and Temperature Measurement

2. Working Parameters

� Operating temperature range

� Unit:

• 0 / 50° C (storage -10/60°C) (capacitive polymer sensor; (GA10,GA20))

• -20 / 55° C (storage -20/60°C) (chilled mirror sensor; (GA25))

� Sensor:

2011 PM-SF6

• +20 / -60 °C dew point (capacitive polymer sensor; (GA10,GA20))

• +20 / -63.9* °C dew point (chilled mirror sensor; (GA25))

*(-63.9°C is the sublimation point of SF6)

� Resolution:

• 1 °CDP (capacitive polymer sensor; (GA10,GA20))

• 0.1 °CDP (chilled mirror sensor; (GA25))

8

Pressure and Temperature Measurement

2. Working Parameters

� Maximum operating pressure

� Gaseous pressure is regulated from 1.5 - 14 bar (a) (22-203 psi) (GA10,GA25)

� Gaseous pressure is regulated from 1.5 – 35 bar (a) (22-508 psi) (GA20)

� Accuracy (note 1st measurement)

� ± 2 °C dew point at +20 °C ... -40 °C, ± 4 °C dew point at < -40 °C for the capacitive polymer sensor

(GA10, GA20)

2011 PM-SF6

(GA10, GA20)

� ± 0.1°C dew point for chilled mirror sensor (GA25)

� Frequency of calibration

� Humidity sensor calibration for the capacitive polymer sensor is recommended every 2 years.

� No calibration is required for the chilled mirror sensor.

9

Pressure and Temperature Measurement

3. SF6 Gas Used During Measurement

� Gas Flow Rate / Amount of gas per sample

Device FlowMeasuring

time*

Gas consumption

/ L (at ambient pressure)

/ g

2011 PM-SF610

* The measuring time depends on the humidity content of the SF6 gas for the humidity

measuring devices.

SF6-Breaker-Analyzer

33 L/h2 - 7 min

1.1 – 3.9 7.2 – 25.4

SF6-%: 3 L/h 0.1 – 0.35 0.7 – 2.3

Humidity: 20L/h 0.7 – 2.3 4.6 – 15.0

SO2: 10 L/h 0.3 – 1.2 2.0 – 7.8

SF6-Humiditor20 L/h 2 - 7 min 0.7 – 2.3 4.6 – 15.0

SF6-Hygrometer25 L/h 5 - 10 min 2.1 – 4.2 13.7 – 27.4

Pressure and Temperature Measurement

3. SF6 Gas Used During Measurement

� Method of gas capture

� SF6 Recovery Kit: SF6 Recovery Bag (on-site collection) and optional SF6 Compressor/Cylinder to reclaim the gas

� Recovery bag holds approx. 30 measurements

� Advantage:

� Highly mobile (a battery operated measuring device can be used)

2011 PM-SF611

� Connectable to nearly all measuring devices

� Lightweight and easy to operate

� Possible to connect directly with a service cart

� Disadvantage:

� It is not possible to pump back the SF6 -gas directly

� Handling of the measured SF6-gas

Pressure and Temperature Measurement

3. SF6 Gas Used During Measurement

� Method of gas capture

� Measuring device with integrated pump back unit and internal cylinder.

� Advantage:

� Convenient: The measured SF6-gas can be pumped back directly after measuring.

� No handling of the measured SF6-gas

� Disadvantage:

2011 PM-SF612

� Weight of the measuring device

� Compressed gas cylinder inside. Possible problems with air transportation if not depressurized.

� Impurities remain inside the system after the measurment and it is possible that these impurities can become

diluted inside the SF6-filled compartment with pure SF6 on subsequent measurements.

� Humidity from the electrochemical sensor (and in case of internal leakages of the measuring device humidity +

air) can unknowingly come into the SF6-filled compartment during pump back.

� Contaminated SF6 (according IEC60480, unsuitable for reuse) will be pumped back into the tank even though it

does not comply with the standard.

� No battery operated system is possible. The compressor adds additional weight and the measuring device must

reboot when it is moved to a new location, increasing the time of each measurement

Pressure and Temperature Measurement

3. SF6 Gas Used During Measurement

� Concern for decomposed SF6 products (gases & particulates)

� High concentrations of decomposition products can damage the electronic humidity modules. Protecting the sensor from these

effects without influence on the reading is not possible.

Recommendation: Flush the sensor with air directly after measuring a high concentration of decomposed gas.

� Chilled mirror measuring systems are nearly unaffected by decomposition products. Possible hazard is more the infrastructure

2011 PM-SF613

� Chilled mirror measuring systems are nearly unaffected by decomposition products. Possible hazard is more the infrastructure

than the mirror itself.

� Humidity measurement without detection of decomposition products increases the risk of sensor damage.

� Use of filters?

� The use of any kind of filter has an influence on the reading of the sensors and / or on the reaction time of the sensor.

Therefore we would not recommend using any kind of filter. Experience shows that a filter is not necessary.

Pressure and Temperature Measurement

4. Conclusion

� Pros of capacitive polymer sensor

� Fast response time of the sensor

� Unaffected by high humidity values

� Cons of capacitive polymer sensor

� Decomposition products in high concentration can damage the sensor.

� Requires calibration every two years. (Chilled mirror measuring device needs no calibration)

Pros of Chilled mirror sensor

2011 PM-SF614

� Pros of Chilled mirror sensor

� High accuracy

� No calibration required

� Con of chilled mirror sensor

� Measurement time is longer (more SF6 gas used)

� Higher flow rate of SF6 gas

Pressure and Temperature Measurement

4. Conclusion

� Instrument selection considerations (GA10)

� Easy to operate

� Fast response time of the humidity sensor

� Detects all critical elements in a single measurement

� Automatic interpretation of results

� Automatic flushing of decomposition product sensor (prolongs sensor life)

2011 PM-SF615

� Automatic flushing of decomposition product sensor (prolongs sensor life)

� Data stored for later analysis (Evaluation software is scope of supply)

� Separate containment chamber for used SF6 gas

� Battery powered, easily portable

� Light weight