International Telecommunication Union
ITU-T Study Group 05
The model
testing/simulations
Yasuhiro Honma
Technical Session on Home Networks
Geneva, 29/04/2011
Outline
ITU-T
o Mechanism of internal ports lightning surge
Study Group 05
o Experiment and Simulation model
o 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
Mechanism of internal port
lightning surge for ONT/HGW
ITU-T
Study Group 05
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.
Customer Premises
Mains power
port
L１
N
Lightning surge
AC/DC Adapter
Optical line port
Optical Fiber
d.c.
L１
ONU/HGW
N
Internal port
Internal port
L2
Telecom equipment 1
N
L2
Telecom
equipment 2
SPD
SPD
Washing machine
Protective earth
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
ITU-T
Overvoltage measured in
experimental house model
Arrangement
Study Group 05
IEnt
VPhase
IPhase
The relation ship between IEnt (current flow on entrance point) and
Vphase/Iphase (Induced voltage and current) was examined experimentally
Spice model
ITU-T
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
Study Group 05
IEnt
Table 1 Simulated parameters
Items
Parameter
R1 = 19 mΩ
Impedance of power line cable between DB and TE１ L1 = 19 uH (Length d1 = 19 m)
R2 = 3 mΩ
Impedance of power line cable between DB and TE2 L2 = 3 uH (Length d2 = 3 m)
Impedance of power line cable between DB and washing
R3 = 6 mΩ
machine
L3 = 6 uH (Length d3 = 6 m)
R4 = 6 mΩ
Impedance of washing machiene grouding cable
L4 = 6 uH (Length d4 = 6 m)
R5 = 1 Ω
Impedance of internal telecommunication cable
L5 = 15 uH (Length d5 = 15 m)
470 V and 270 V. diode
Telecommunication equipment
An appliance with earthed SPDs
Loop inductance between phases
Loop inductance of drop cable
1800 V. diode
60 uH
270uH
Technical Session - Home Networks - Geneva
VPhase
IPhase
Overvoltage measured in
experimental house model Visuals
ITU-T
Study Group 05
Technical Session - Home Networks - Geneva
Results (1) waveforms
Experiment and Simulation
IEnt
ITU-T
Study Group 05
IPhase
VPhase
VPhase A
VPhase B
IEnt
Technical Session - Home Networks - Geneva
Results (2) Peak values
Relation between IEnt and Vphase , Iphase
ITU-T
V phase  0.47  I entrance  1500
Study Group 05
V 
7.5kA ⇒5kV
Iphase Current [A]
Vphase Voltage [kV]
60
50
40
30
20
10
0
0
1
IEnt [kA]
Figure 1 Relation between IEnt and Vphase
Technical Session - Home Networks - Geneva
2
IEnt [kA]
3
4
5
ITU-T
Study Group 05
Cumulative occurrence frequency
[times/thunder storm day]
Observed lightning current on
AC mains port
Measurement period: 3 months.
Frequency of currents >1 kA
= 0.0009 per thunderstorm day.
Frequency of currents >3 kA
= 0.00015 per thunderstorm day.
1.5
P  37.6  Aentrance
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”
EMC’04/Sendai
Technical Session - Home Networks - Geneva
Calculation between Failure
rate and Internal ports voltage
ITU-T
Study Group 05
(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 ,
R
1
PCO  FA
100 DTS
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
Technical Session - Home Networks - Geneva
Calculated results;
Failure rate and Internal port voltage
15 thunderstorm days
ITU-T
Failure Rare[%]
RFA
Study Group 05
0.1
0.05
0.01
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.
Currents flow on
Induced voltage [kV]
Entrance Point [kA]
Vphase
IEnt
6.8
11
32
4.7
6.6
16
20 thunderstorm days
Failure Rare[%]
RFA
0.1
0.05
0.01
Currents flow on
Induced voltage [kV]
Entrance Point [kA]
Vphase
Ient
8.3
13
38
5.4
7.7
20
30 thunderstorm days
Failure Rare[%]
RFA
0.1
0.05
0.01
Currents flow on
Induced voltage [kV]
Entrance Point [kA]
Vphase
Ient
11
17
50
Technical Session - Home Networks - Geneva
6.6
9.6
25
Consideration on AC mains
distribution system
ITU-T
Study Group 05
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
Telecomm. equipment 1
Internal cable
Telecomm. equipment 2
L1
PEN
N
PE
Home appliance
Earthing at
the source
Earthing in
the distribution
Fig. 14/TD 562 TN-C-S system (case 4)
The internal ports voltage may occur.
Technical Session - Home Networks - Geneva
ITU-T
Overvoltage measured in
experimental house model
Arrangement
Study Group 05
IEnt
VPhase
IPhase
The relation ship between IEnt (current flow on entrance point) and
Vphase/Iphase (Induced voltage and current) was examined experimentally
Conclusion
ITU-T
Study Group 05
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.
Technical Session - Home Networks - Geneva