maintenance and recovery of hv electricity transport ... workshop dlr bakic for... ·...

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Kresimir Bakic, CIGRE & ELES, Slovenia

Beograd, 6 November 2014

SLOVENIJA 2014

STATE-OF-THE-ART FOR DYNAMIC LINE RATING TECHNOLOGY

Future Vision

"Maintenance and recovery of HV electricity transport

systems and aerospace assistance"

Plan of presentation

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1. INTRODUCTION – Why we need DLR?

2. POSIBLE SENSORS FOR DLR

3. WHAT IS THE KEY ISSUE FOR LINE MONITORING? STATIC VALUE, DYNAMIC VALUE, +++ PREDICTIONS

4. TECHNOLOGY BASED ON WEATHER STATIONS

5. TECHNOLOGY BASED ON TENSOR CELLS

6. TECHNOLOGY BASED ON CONDUCTOR TEMPERATURE

7. TECHNOLOGY BASED ON CONDUCTOR VIBRATION

8. TECNOLOGY BASED ON FIBER OPTIC

9. TECHNOLOGY BASED ON SAG MONITORING DEVICE

10. TECHNOLOGY BASED ON DGPS – SATTELITE MONITORING

11. MY VISION ON SATELLITE AIDED OHL MONITORING - CONDUCTOR: SAG, TEMPERATURE, ICING

- TOWER: TENSION, SAG

- CORRIDOR: VEGETATION MANAGEMENT

- WEATHER CONDITION ??? GROUND LEVEL WIND FLOW ???

- RECOVERING SUPPORTS DURING LARGE WEATHER STORMS, SPACE STORMS

Kresimir Bakic, CIGRE Slovenia

INTRODUCTION

3 Kresimir Bakic, CIGRE Slovenia

100

%

200% C

AP

AC

ITY

IN

CR

EA

SE

COST

Base Case:

New Line:

Cost = 100%

Capacity=100% 100%

0 25% 50%

75% 3

4

5

300%

1, 2

6

1 Real Time Monitoring

2 Probabilistic Rating

3 Conductor Retention

4 Conductor Change

5 Voltage Increase

6 Conversion to DC

CIGRE WG

B2/C1 - 19

TECHNOLOGIES FOR INCREASING

CAPACITY OF OHLs - DLR solution - cheapest

- Older OHLs with high loads

- Carefuly with losses

New HTLS conductors

(ACCC) could be more

competitive than investment

in non-reliable monitoring.

Why we need DLR?


INTRODUCTION Criteria for decision

of Technology

1. ECONOMY 2. RELIABILITY (supply method, ICT – transmission) 3. ACCURACY (± 5 A) and for SAG (± 20 cm) 4. PLACING (with or without switching off line)

Economy of cable or OHL Capacity of Cable or OHL

Source: CIGRE WG B2/C1 - 19

5 Kresimir Bakic, CIGRE Slovenia Source: EPRI, Future Inspection of OHL, 2008

TECHNOLOGIES FOR OHL MONITORING

Main parts of technology:

- sensors,

- information transmission.

Monitoring of

- electrical, thermal, mechanical

and atmospheric parameters.

SENSORS TECHNOLOGIES: - optical, infrared, ultra-violet, satellite imagery, - surface acoustic waves (SAW), - vibration sensors, conductor temperature sensors, - LIDAR (Laser Imaging Detection And Ranging), - tensor load cells, strain sensors, - wind measure with ultrasonic anemometers, etc.


rp

sp

RI 2

cp

mW cooling Radiation-

mW cooling Convection -

mW heatingSolar -

mW heating Joule -

mW

r

c

s

j

rcsj

p

p

p

p

pppp

Condition State Steady Under

Direct or BeamSolar Radiation

Sky or Diffuse Solar RadiationImaginary BoundaryRepresenting Sky andSurrounding

Portion NotAbsorbed byConductor

Horizontal ConductorOriented in Air with WindNormal to Conductor

Win

d

rp

sp

2

cp

mW cooling Radiation-

mW cooling Convection -

mW heatingSolar -

mW heating Joule -

mW

r

c

s

j

rcsj

p

p

p

p

pppp

Thermal balance equation

Main atmospheric parameters are wind, wind direction, ambient temperature and solar

7

Temperature in atmosfere

8

WHAT IS THE KEY ISSUE FOR LINE

MONITORING?

STATIC VALUE

DYNAMIC VALUE

PREDICTIONS

Ampacity of a conductor is that maximum constant current which will meet the design,

security and safety criteria of a particular line on which the conductor is used.

Static rating is the simplest thermal rating system based on “ampacity Tables” provided by the

conductor manufacturer or calculated based on worst weather case. Using such tables, the “normal” or „continuous”

thermal rating of each conductor is specified for certain weather conditions and conductor parameters.

Conservative approach based on worst weather case.

Real-time monitoring – many different technologies.

Some technologies more effective during system normal

operation and other during system contingency.

Real added value for monitoring systems.

Key issues related to wind predictions in the OHL corridor

in so different terrains.

Global error margin for real-time rating acceptable for operators should be ± 10%.

Conditions for conservative thermal ratings:

1) Wind speed: 0,6 m / s perpendicular wind, 2) Ambient temperature 30 - 350 C, 3) Solar radiation 900-1000 W/m2 ; 4) Conductor absorptivity 0.5 – 0.6

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From CIGRE brochure 299 “Guide for selection of weather parameters for

bare overhead conductor ratings”:

• The average temperature of a line section will not exceed the maximum

design temperature by more than 10 °C, even under exceptional situations, and will provide a confidence level of at least 99% that the conductor temperature will be less than the design temperature when the line current equals the line rating.

• The highest local conductor temperature will not exceed the maximum design temperature by more than 20 °C when the line current equals the line rating. • Because ratings based on probabilistic clearances require consideration of other criteria than weather parameters (load probabilities, traffic under the lines etc.) their application is not included in this document. • This and other related documents discuss sag and tension calculations only in a general manner. The document recognizes that maintaining adequate

clearances is usually the primary objective of line ratings and that conservatism in sag calculations can mitigate the consequences of too optimistic rating assumptions. Yet, such combination may not be applicable in all circumstances.

• For ensuring adequate clearances, it is recommended that the transmission owner verifies their actual line clearances at appropriate intervals.

GOOD TO KNOW

10

Static rating

2m/s

1m/s

0.6m/s

Static rating

STATIC RATING

Source: from CIGRE JWG C1-B2 - 19


TECHNOLOGIES FOR THERMAL OHL MONITORING

-Ampacimon (vibration)

Conductor surface temperature

DONUT

Load cell (Tensor)

Surface Acoustic Waves (SAW),

Weather sta.

Source: from CIGRE TB 498


1. TECHNOLOGY BASED ON WEATHER STATIONS

Weather station in ROW

Indirect Method

Calculating in-span Conductor temperature from a weather station. (CIGRE Bros. 207)

RTM system

The purpose of real-time monitoring is to determine, in real-time, the position of the conductor in space

conductor replica (SHAW technologies)


2. TECHNOLOGY BASED ON TENSOR CELLS

RTM system

SOURCE: CIGRE TB 498


3. TECHNOLOGY BASED ON CONDUCTOR TEMPERATURE

RTM system

SOURCE: CIGRE TB 498, from 2012

DONUT device clamped on conductor of OHL

Other type of conductor temperature is fiber optic measurement inside conductor. (4)

Temperature on surface of conductor


5. TECHNOLOGY BASED ON SAG MONITORING DEVICE

RTM system

SOURCE: CIGRE TB 498, from 2012

camera target


6. TECHNOLOGY BASED ON VIBRATION SENSOR

Fundamental

Frequency [Hz]

Sag [m]

0.1367 ± 4

10-4 16.40 ± 0.1

Principles behind Ampacimon

• Ampacimon detects low frequencies (accelerometers)

• The sag is determined via the main vibration mode

• Only the frequency is needed, not the amplitude

• No calibration is required • The accuracy of the measured sag depends on

the sampling frequency (approximately 2%) • Measurements are processed using the

Fourier transformations method


Technology Use Where/how? How long?

Weather station wide No switch off 30 years

Load cell (Tensor) USA, EU Switch off line

On tower

20 years

Conductor surface temperature (Donut)

limited Switch off line On conductor in suitable span

20 years

Conductor inside temperature (Optical fiber)

limited Switch off line In conductor.

10 years

Sag measures (video, satellite imagery)

limited No switch off

Markers

10 years

Conductor vibration (Ampacimon)

Pilot

projects

Switch off line On conductor in suitable span

5 years

TECHNOLOGIES FOR THERMAL OHL MONITORING comparison

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TECHNOLOGY BASED ON DIFFERENTIAL GLOBAL

POSITIONING SATELLITE (DGPS)

Method for measure sag by DGPS. Capable of measuring sag to

accuracy of appr. 25 mm using commercially available GPS.

Method measures conductor to ground based on altitude information

obtained from GPS device.

Weakness of GPS: noise by radio signals, atmospheric conditions, etc.

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INFORMATION SYSTEM FOR OPERATORS BASED ON ANY SENSOR –

DEVELOPMENT IN ELES SLOVENIA


An Attempt to develop innovative TECHNOLOGY

System based on Strain gauges

Measurements of fundamental

frequency and deformation

The measurement was carried out by sensors that were

attached to the legs of the towers, namely:

deformation gauges (resistance measuring gauges in

longitudinal and transverse direction) and also the

accelerometer and temperature gauges-tower.

DEVELOPMENT IN ELES, Slovenia, 2014


An Attempt to develop strain gauges approch

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VISION ON OHL MONITORING AIDED BY SATELLITES

CONDUCTOR: SAG, TEMPERATURE, ICING

TOWERS: DEFORMATIONS

CORRIDORS: VEGETATION MANAGEMENT

PREDICTIONS – GROUND LEVEL WIND FLOW

RECOVERING SUPPORTS DURING LARGE

WEATHER STORMS, SPACE STORMS


1 Development of sensor technologies as well as ICT has resulted in

the formation of the number of new monitoring technologies for

OVERHEAD power lines.

2. DLR is the cheapest approach to increase capacity, but decision

of technology needs very careful selection: method of data transfer

and the accuracy of the sensor.

3. New innovative methods as strain gauges and differential Global

Positioning Systems using satellites could be very promising

technologies for OHLs.

SOME CONCLUSIONS

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• Using National Weather Service forecast?

• Or to develop own tool?

1. Persistence models and combination -(models are in class of easy predictions models - plain predictor)

2. Statistical approaches -(time-series analyses, ARIMA, wavelet,...)

3. Data mining approaches (ANN) - Next generation of wind forecasting technology (Regime

switching space-time algorithms)

Approaches to predictive rating methods

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76

Lag

ACF

-0,5

0

0,5

1

1,5

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171

Lag

ACF

Bericevo (Wind speed prediction: Feedforward network wih 45 inputs,10 in the hidden layer

and 1 output)

0

1

2

3

4

5

6

7

Time (22.01.06 00:00 -28.01.06 23:55 )

Win

d s

pe

ed

(m

/c)

Real

Prediction

Podlog (Wind speed prediction: Feedforward network wih

52 inputs,20 in the hidden layer and 1 output)

0

1

2

3

4

5

6

Time (22.01.06 00:00 -28.01.06 23:55 )

Win

d s

peed m

/cReal

Prediction

Autocorrelation function for wind speed

Predictions for wind speed for 4 hours – ANN method

Comparison between real and predicted values

for wind speed in two different S/S

– 45 input neurons, 10 hide, 1 output – 52 input neurons, 20 hide, 1 output

S/S 1 S/S 2

Evaluation of flexible line capacity

Present approach: - Fixed or seasonal OHL rating,

- DLR using monitoring systems

without predictions.

Future approach:

- Use of a new technology (ICT, protection

schemes) and new mathematical

modeling for predictions will enables

dynamic evaluation of line capacity

and flexible line capacity for trade,

But take care: Maybe new type of HTLS conductors

can offer you better flexibility for

same cost or even cheaper.

maintenance and recovery of hv electricity transport ... workshop dlr bakic for... ·...

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