international telecommunication union itu-t study group 05 the model testing/simulations yasuhiro...

International Telecommunication Union

ITU-T Study Group 05

The model The model testing/simulationstesting/simulations

Yasuhiro Honma

Technical Session on Home NetworksGeneva, 29/04/2011

ITU-TStudy Group 05

Outline

o Mechanism of internal ports lightning surgeo Experiment and Simulation modelo Relation between AC mains lightning surge

current and induced Internal port surge voltage/current

o Occurrence probability of AC mains surge current

o Estimation for relation between Failure rate and test levels

o Conclusion

Technical Session - Home Networks - Geneva

ITU-TStudy Group 05

L１

N

L2

L１

N

N

L2

ONU/HGW

SPD

SPD

Optical Fiber

AC/DC Adapter

d.c.

Mains power port

Telecom equipment 1

Telecomequipment 2

Internal port

Customer Premises

Washing machine

Lightning surge

Protective earth

Internal port

Optical line port

L１

N

L2

L１

N

N

L2

ONU/HGW

SPD

SPD

Optical Fiber

AC/DC Adapter

d.c.

Mains power port

Telecom equipment 1

Telecomequipment 2

Internal port

Customer Premises

Washing machine

Lightning surge

Protective earth

Internal port

Optical line port

Mechanism of internal port lightning surge for ONT/HGW

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

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.

ITU-TStudy Group 05

Overvoltage measured in experimental house model

Arrangement

IEnt

VPhase

IPhase

The relation ship between IEnt (current flow on entrance point) and Vphase/Iphase (Induced voltage and current) was examined experimentally

ITU-TStudy Group 05

Spice model


VPhase

IPhase

IEnt

Items ParameterImpedance of power line cable between DB and 　 TE１

R1 = 19 mΩL1 = 19 uH (Length d1 = 19 m)

Impedance of power line cable between DB and　 TE2 R2 = 3 mΩL2 = 3 uH (Length d2 = 3 m)

Impedance of power line cable between DB and washing machine

R3 = 6 mΩL3 = 6 uH (Length d3 = 6 m)

Impedance of washing machiene grouding cable R4 = 6 mΩL4 = 6 uH (Length d4 = 6 m)

Impedance of internal telecommunication cable R5 = 1 ΩL5 = 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

Table 1 Simulated parameters

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

ITU-TStudy Group 05

Overvoltage measured in experimental house model Visuals


ITU-TStudy Group 05

Results (1) waveformsExperiment and Simulation


VPhase A

VPhase B

IEnt

VPhase

IPhase

IEnt

ITU-TStudy Group 05

Results (2) Peak valuesRelation between IEnt and Vphase , Iphase


VIV entrancephase 150047.0

IEnt [kA]

Vph

ase V

olta

ge [

kV]

7.5kA ⇒ 5kV

IEnt [kA]

I phas

e Cur

rent

[A

]Figure 1 Relation between IEnt and Vphase

ITU-TStudy Group 05


Lightning current peak value [A]Cum

ulat

ive

occu

rren

ce f

requ

ency

[t

imes

/thun

der

stor

m d

ay]

5.16.37 entranceAP

Measurement period: 3 months.Frequency of currents >1 kA = 0.0009 per thunderstorm day.Frequency of currents >3 kA = 0.00015 per thunderstorm day.

J.Kato T.Tominaga et.al, “Measurement results of Lighting surge current on ac mains line connected to access network equipment” EMC’04/Sendai

Figure 2 Relation between lightning current peak value and occurrence frequency

Observed lightning current on AC mains port

ITU-TStudy Group 05

Calculation between Failure rate and Internal ports voltage


(1) Estimation for occurrence probability of IEnt

TS

FACO D

RP

1

100

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

ITU-TStudy Group 05

Calculated results;Failure 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 4.70.05 11 6.60.01 32 16


Failure Rare[%]RFA


Ient


0.1 8.3 5.40.05 13 7.70.01 38 20


Failure Rare[%]RFA


Ient


0.1 11 6.6 0.05 17 9.6 0.01 50 25

On average 20 thunderstorm days per year15 million users of optical network equipment in Japan. If the failure rate assumes 0.05 %, the 7500 failures per year will occur.

ITU-TStudy Group 05

Consideration on AC mains distribution system


L1PEN

PE

Earthing at the source

Earthing in the distribution

Telecomm. equipment 1

Internal cable

Telecomm. equipment 2

N

Home appliance

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 562:Evaluation 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.

ITU-TStudy Group 05

Overvoltage measured in experimental house model

Arrangement

IEnt

VPhase

IPhase

The relation ship between IEnt (current flow on entrance point) and Vphase/Iphase (Induced voltage and current) was examined experimentally

ITU-TStudy Group 05

Conclusion

o Introduced the mechanism of lightning over-voltage applied between the internal ports for ONT/HGW.

o Derived a relationship between the AC mains lightning current and internal ports voltage/current from the experiment and simulation.

o 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.


international telecommunication union itu-t study group 05 the model testing/simulations yasuhiro...

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