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Impact of modelling of transmission network components on the emission limits for distorting loads in HV system Rizah Memisevic 17 February 2011 Contents 1 Frequency scan analysis 1000 100 Self Impedance Networkimpedance Angle 900 80

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Impact of modelling of transmission network components on the emission limits for distorting loads in HV system

Rizah Memisevic 17 February 2011

Contents

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SLIDE 2

2 Frequency scan analysis

100 200 300 400 500 600 700 800 900 1000 1 2.5 4 5.5 7 8.5 10 11.5 13 14.5 16 17.5 19 20.5 22 23.5 25 26.5 28 29.5 31 32.5 34 35.5 37 38.5 40 41.5 43 44.5 46 47.5 49 Self Impedanze (Ohm) Harmonic

Self Impedance

Pi model Network Impedance, Magnitude in Ohm Distributed Model Network Impedance, Magnitude in Ohm

  • 100
  • 80
  • 60
  • 40
  • 20

20 40 60 80 100 1 2.5 4 5.5 7 8.5 10 11.5 13 14.5 16 17.5 19 20.5 22 23.5 25 26.5 28 29.5 31 32.5 34 35.5 37 38.5 40 41.5 43 44.5 46 47.5 49 Angle (deg) Harmonic

Networkimpedance Angle

Pi model Networkimpedance, Angle in deg Distributed Model Networkimpedance, Angle in deg

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100 200 300 400 500 600 700 800 900 1000 1 2.5 4 5.5 7 8.5 10 11.5 13 14.5 16 17.5 19 20.5 22 23.5 25 26.5 28 29.5 31 32.5 34 35.5 37 38.5 40 41.5 43 44.5 46 47.5 49 Self Impedance (Ohm) Harmonic

Self Impedanze

Distributed Model Network Impedance, Magnitude in Ohm Freq.Dep.Tr. Model Network Impedance, Magnitude in Ohm

  • 100
  • 80
  • 60
  • 40
  • 20

20 40 60 80 100 1 2.5 4 5.5 7 8.5 10 11.5 13 14.5 16 17.5 19 20.5 22 23.5 25 26.5 28 29.5 31 32.5 34 35.5 37 38.5 40 41.5 43 44.5 46 47.5 49 Angle (deg) Harmonic

Netwrok impedance Angle

Distributed Model Networkimpedance, Angle in deg Freq.Dep.Tr. Model Networkimpedance, Angle in deg

The skin effect of the transmission line

  • re

the external radius of conductor (m)

  • ri

the internal radius of conductor (m)

  • J0

is the Bessel function of the first kind and zero order

  • J’0

is the derivative of the Bessel function of the first kind and zero

  • rder
  • N0

is the Bessel function of the second kind and zero order

  • J’0

is the derivative of the Bessel function of the second kind and zero order

  • σc

is the conductivity of the conductor material at the average conductor temperature

  • f

is frequency (Hz)

  • is the permeability of free space
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SLIDE 4

4 Correction factors for skin effect in overhead lines

Voltage (kV) Harmonic order Resistance NGC 400, 275 h≤4.21 4.21<h ≤7.76 h>7.76 NGC 132 EDF 400, 225 h≤4 4<h<8 h>8 EDF 150, 90

Correction for skin effect in overhead lines according to EDF & NGC

5 10 15 20 25 30 35 40 45 50 1 1.5 2 2.5 3 3.5 4

Harmonic Rh/R1 Corrections for skin effect in overhead lines

EDF 400kV & 225 kV NGC 400kV & 275kV EDF & NGC 150kV & 132kV & 90kV

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Voltage (kV) Coefficient a Coefficient b NGC 400, 275 0.2401 0.6434 NGC 132 0.0985 0.6562 EDF 400, 225 0.2286 0.6486 EDF 150, 90 0.0985 0.6562

Correction for skin effect in over headlines - EDF 400 kV & 225 kV / Frequency polynomial function Correction for skin effect in over headlines - NGC 400 kV & 275 kV / Frequency polynomial function

5 10 15 20 25 30 35 4 45 5 1 1 .5 2 2 .5 3 3 .5 4

Harmon ic Rh/R1 Corrections for skin effect in overhead lin es - Frequency polynomial characteristic

EDF 400kV & 225 kV Freque ncy po l ynomial characteristic 5 10 15 20 25 30 35 40 45 50 1 1.5 2 2.5 3 3.5 4 Harmonic Rh/R1 Co rrections for skin e ffect in ove rhead lines - Fre quency po lyno mial characte ristic NGC 400kV & 275kV Frequency polynom ial characteristic
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6 Correction for skin effect in over headlines - EDF / NGC 150 kV / 132 kV and 90 kV - Frequency polynomial function

5 10 15 20 25 30 35 40 45 50 1 1.2 1.4 1.6 1.8 2 2.2 2.4

Harmonic Rh/R1 Corrections for skin effect in overhead lines - Frequency polynomial characteristic

EDF & NGC 150kV & 132kV & 90kV Frequency polynomial characteristic 100 200 300 400 500 600 700 800 900 1 2.5 4 5.5 7 8.5 10 11.5 13 14.5 16 17.5 19 20.5 22 23.5 25 26.5 28 29.5 31 32.5 34 35.5 37 38.5 40 41.5 43 44.5 46 47.5 49 Self Impedance (Ohm) Harmonic

Self impedance

  • Freq. dep. resistance of Tr. Network Impedance,

Magnitude in Ohm Series Resistances as the Vector Characteristics Network Impedance, Magnitude in Ohm Series Resistance as the Frequency Polynomial Characteristics Network Impedance, Magnitude in Ohm

  • 80
  • 60
  • 40
  • 20

20 40 60 80 100 1 16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301 316 331 346 361 376 391 406 421 436 451 466 481 Angle (deg) Harmonic

Network Impedance Angle

  • Freq. dep. resistance of Tr. Networkimpedance,

Angle in deg Series Resistances as the Vector Characteristics Networkimpedance, Angle in deg Series Resistance as the Frequency Polynomial Characteristics Networkimpedance, Angle in deg

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Conclusions related to the self impedances of the busbar concerning different modelling approaches of the skin effect:

  • There is no significant impact of the modelling of the skin effect on the

complex self impedance for harmonics lower than 8th harmonic.

  • The impact of the skin effect on the self impedance of the busbar

increase with the order of the harmonic.

  • Skin effect has the biggest impact on the busbar self impedance at

resonant frequencies. At resonant frequencies, the amplitude of the self impedance can be reduced up to 50% if the skin effect of the transmission lines has been modelled. Taking this into account the modelling of the skin effect of transmission lines can be seen as being critical for all frequency scan analysis.

  • Modelling of skin effect does not have any impact on the resonance

frequencies of the self impedances

  • There are no significant differences between two analysed modelling

methodologies of the skin effect: the frequency polynomial functions and vector characteristics. The frequency polynomial function is simpler and much easier to apply which is a major advantage of this methodology.

  • We notice that modelling of skin effect has an impact on the network

impedance angle; however we are not able to identify any importance of this on the filter design or harmonic allocation.

Emission limits for distorting loads in HV - EHV systems

  • Stage 1
  • Stage 2
  • 1 is the considered node and 2, 3, … the other nodes
  • St1, St2, St3, … the total available power of the network at

the point of common coupling (total supply capability)

  • h harmonic order
  • Kh2-1, Kh3-1, Kh4-1, … the influence coefficients. The

influence coefficient Khj-i is the harmonic voltage of order h which is caused at node i when 1 p.u. harmonic voltage

  • f order h is applied at node j.
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  • EUHi is the voltage emission limit of a consumer i at

harmonic h

  • LhHV is the planning level of the hth harmonic in HV or

EHV systems see Standard

  • Si

is the rating of the consumer

  • α

is the summation law exponent, see Standard

  • FHV is the coincidence factor for HV loads, typical values

are between 0.4 and 1.

  • Bh

is the background harmonic level higher than normal share

  • SB

is the already connected power responsible for background level Bh

  • Khi-j is the greatest influence coefficient greater than 1.
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9 Voltage emission limits, 40 MVA load Voltage emission limits with and without resonance effect, 40 MVA load

0.2 0.4 0.6 0.8 1 1.2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Alloc ated Limit (%) Harmonic

Voltage Emission Limits

Allocate d Limit(%) Pi Line Model Allocate d Limit(%) Distr. Line Model Allocate d Limit(%) Freq.Dep.R.Tr. Allocate d Limit(%) Polynomial Characteristics Allocate d Limit (%) Vector Characteristics 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Allocated Limit (%) Harmonic

Voltage Emission Limits - Vector Chacteristics

Allocated Limit (%) Vector Characteristics Allocated Limit(%) (Resonance taken into account) Vector Characteristics

Current emission, 40 MVA load

EIHi is the current emission limit of a consumer i at harmonic h Zhi is the self impedance at node i at harmonic h

50 100 150 200 250 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Current Limit (A) Harmonic

Current Emission Limits

Allocated Limit(A) Allocated Limit(A) & Res.

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10 Voltage emission limits, 500 MVA load Current emission limits, 500 MVA

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Allocated Limit (%) Harmonic

Voltage Emission Limit

Allocated Limit(%) Allocated Limit(%) (Resonance taken into account) 50 100 150 200 250 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Curre nt Limit (A) Harmonic

Current Emission Limits

Allocated Limit(A) Allocated Limit(A) & Res.

Conclusions Questions

Rizah Memisevic Phone Number : +61 7 3866 1432 Fax Number : +61 7 3866 1222 Mobile Number: +61 0421650682 E-mail : rmemisevic@powerlink.com.au