The model testing/simulations

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The model testing/simulations

• Yasuhiro Honma

Technical Session on Home Networks Geneva,
29/04/2011
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Outline

• Mechanism of internal ports lightning surge
• Experiment and Simulation model
• Relation between AC mains lightning surge current
  and induced Internal port surge voltage/current
• Occurrence probability of AC mains surge current
• Estimation for relation between Failure rate and
  test levels
• Conclusion

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Mechanism of internal port lightning surge for
ONT/HGW
Even fiber optic ONT/HGW equipment, if telecom.
equipment is connected to the port which uses AC
mains power, the surge voltage is generated
during the internal ports.
Case 2 Damage occurred between two internal
ports of telecom equipment Damage Telecom. Equip
1 (FAX), Home Gate Way Telecom. equip 2
(PC) Route AC mains(1) TE1 -- HGW TE2 SPD
Local PE
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Overvoltage measured in experimental house model
Arrangement
VPhase
IEnt
IPhase
The relation ship between IEnt (current flow on
entrance point) and Vphase/Iphase (Induced
voltage and current) was examined experimentally
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Spice model
To investigate the effect of wire length,
amplitude of entrance point current and so on,
the results were compared between the SPICE
simulation and experiment
IEnt
Table 1 Simulated parameters
Items Parameter
Impedance of power line cable between DB and TE1 R1 19 mO L1 19 uH (Length d1 19 m)
Impedance of power line cable between DB and TE2 R2 3 mO L2 3 uH (Length d2 3 m)
Impedance of power line cable between DB and washing machine R3 6 mO L3 6 uH (Length d3 6 m)
Impedance of washing machiene grouding cable R4 6 mO L4 6 uH (Length d4 6 m)
Impedance of internal telecommunication cable R5 1 O L5 15 uH (Length d5 15 m)
Telecommunication equipment 470 V and 270 V. diode
An appliance with earthed SPDs 1800 V. diode
Loop inductance between phases 60 uH
Loop inductance of drop cable 270uH
VPhase
IPhase
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Overvoltage measured in experimental house model
Visuals
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Results (1) waveformsExperiment and Simulation
IEnt
IPhase
VPhase A
VPhase
VPhase B
IEnt
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Results (2) Peak valuesRelation between IEnt and
Vphase , Iphase
Iphase Current A
IEnt kA
Figure 1 Relation between IEnt and Vphase
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Observed lightning current on AC mains port
Measurement period 3 months. Frequency of
currents gt1 kA 0.0009 per thunderstorm
day. Frequency of currents gt3 kA 0.00015
per thunderstorm day.
Cumulative occurrence frequency times/thunder
storm day
Lightning current peak value A
Figure 2 Relation between lightning current peak
value and occurrence frequency
J.Kato T.Tominaga et.al, Measurement results of
Lighting surge current on ac mains line connected
to access network equipment EMC04/Sendai
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Calculation between Failure rate and Internal
ports voltage
(1) Estimation for occurrence probability of IEnt
Assuming the Failure rate RFA and the
thunderstorm days per year DTS Day/year , The
Occurrence Probability of IEnt is obtained by
following equation ,
From the occurrence probability of IEnt, the
maximum current flow on entrance point IEnt is
obtained by Figure 2
(2) Estimation for Internal ports voltage of
Vphase
From the expected current flow of IEnt, the
expected internal voltage VPhase is obtained by
Figure 1
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Calculated resultsFailure rate and Internal
port voltage
15 thunderstorm days
Failure Rare RFA Currents flow on Entrance Point kA IEnt Induced voltage kV Vphase
0.1 6.8 4.7
0.05 11 6.6
0.01 32 16

20 thunderstorm days
Failure Rare RFA Currents flow on Entrance Point kA Ient Induced voltage kV Vphase
0.1 8.3 5.4
0.05 13 7.7
0.01 38 20

30 thunderstorm days
Failure Rare RFA Currents flow on Entrance Point kA Ient Induced voltage kV Vphase
0.1 11 6.6
0.05 17 9.6
0.01 50 25
On average 20 thunderstorm days per year 15
million users of optical network equipment in
Japan. If the failure rate assumes 0.05 , the
7500 failures per year will occur.
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Consideration on AC mains distribution system
We reported that the lightning overvoltage
between the internal ports of telecommunications
equipment that used an optical line occurred due
to lightning surges from the electric power line
in the TT system (Japanese). We also evaluated
the lightning overvoltage generated at the
internal telecommunication ports for various
system earthings. See TD 562Evaluation of
lightning overvoltage at internal
telecommunication ports for various system
earthings
Fig. 14/TD 562 TN-C-S system (case 4)
The internal ports voltage may occur.
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Overvoltage measured in experimental house model
Arrangement
VPhase
IEnt
IPhase
The relation ship between IEnt (current flow on
entrance point) and Vphase/Iphase (Induced
voltage and current) was examined experimentally
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Conclusion

• Introduced the mechanism of lightning
  over-voltage applied between the internal ports
  for ONT/HGW.
• Derived a relationship between the AC mains
  lightning current and internal ports
  voltage/current from the experiment and
  simulation.
• Assuming the failure rate is 0.05, and
  thunderstorm days is 30 day, the internal ports
  voltages was estimated, the calculated voltage
  was almost 10 kV.