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The need for special requirements

The need for special requirements. Tetsuya Tominaga. Technical Session on Home Networks Geneva , 29/04/2011. AC mains plugs in global. There are many plugs in the world There is no earth terminal in Japanese type. JAPANESE TYPE. Japanese customer premises AC power. Voltage: 100 V rms

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The need for special requirements

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  1. The need for special requirements Tetsuya Tominaga Technical Session on Home Networks Geneva, 29/04/2011

  2. AC mains plugs in global • There are many plugs in the world • There is no earth terminal in Japanese type JAPANESE TYPE Technical Session - Home Networks - Geneva

  3. Japanese customer premises AC power • Voltage: 100 V rms • Frequency: • • 50 Hz Eastern Japan • • 60 Hz Western Japan • Configuration: TT Each PE has each grounding rod Technical Session - Home Networks - Geneva

  4. Smart House is “Connected House” Many kinds of equipment will be connected each other under the TT system. Optic Fiber Smart Meter SPD：Surge Protective Device TTC WorkShop

  5. Bad installation and insufficient resistibility Good installation and Adequate resistibility are needed. Optic Fiber Smart Meter SPD：Surge Protective Device TTC WorkShop

  6. Philosophy of protection Good installation and Adequate resistibility of equipment Classification of interface (K.75) Adequate Resistibility (K.21,K.44,K.66,K.71,K.hnwr) Optic Fiber SPD SPD SPD Additional Protection (K.66) Good Bonding (K.66) Who knows K.66? Is Japanese type grounding configuration special? TTC WorkShop SPD：Surge Protective Device

  7. Figure 1/K.hnwr - Flowchart for determining required level of resistibility Figure 1/K.hnwr - Flowchart for determining required level of resistibility Identify the equipment and the number and type of ports Determine the power induction limits Are there unique problems requiring high isolation values? Yes Does the equipment have more than one port type? No Yes Are the power induction limits > 600 V? No Yes “Special” “Enhanced” “Basic” No Selection for Required resistibility(K.hnwr/Draft) Bad bonding configuration (K.66 For example, the bonding wire length >1.5m ) 5.2 Resistibility Recommendation K.21 has two levels of resistibility “basic” and “enhanced”. Specification EN 50468:2009 gives advice on the selection of “basic” and “enhanced”. EN 50468:2009 advises: For equipment having only external telecommunication ports the resistibility requirements are defined in ITU-T K.21 “Basic level”. For equipment having additional connections to networks e.g. power networks, the test levels are defined in ITU-T K.21 “Enhanced level” The required level of resistibility can be determined in Figure 1/K.hnw. Information on “Special requirements” is contained in K.44. When the bonding configuration is not along with K.66 Figure 1/K.hnwr - Flowchart for determining required level of resistibility TTC WorkShop

  8. Proposal: Special Resistibility(K.44, K.66,K.hnwr) The special level is already described in K.44 and K.66. The external port is optical fibre now. So, All telecom. Ports are “Internal” The proposal is adequate Internal port test levels Table II.6-1/K.44 – Resistibility and safety requirements of customer premises equipment powered by mains power Under Study Proposal Technical Session - Home Networks - Geneva

  9. Concideration Un safe method Class II without earthed SPDs Safe method Class II with earthed SPDs A A • Resistibility of inherent IC’s or circuit is becoming smaller, so it becomes more difficult to prevent the damage. • No Earth is Un safe? Safety = Breaking Fuse Minimize of Damage ratio = No Breaking Fuse N Coordination of “protecters” and “Safety and Lightning protection” are important. N The impedance is need for coordination between SPDs E FUSE E V0 SPD2 SPD1 V2 V1 Coordination of protection Safety and lightning Protection in no earth TTC WorkShop

  10. Bypass circuit and Safety standard • Conflict between Safety standards (e.g. IEC 60950) and Lightning protection (Recommendation K.66 and so on). • Bypass circuits between AC mains and telecom ports described in K.66 should be permitted in any case to protect telecommunication equipments against overvoltages. • The protector operate voltage would be higher than the insulation test voltage. Unfortunately the safety standards, e.g. IEC 60950, do not allow voltage limiters to bridge supplementary insulation, double insulation or reinforced insulation. TD566 is describe in detail, please read them. Technical Session - Home Networks - Geneva

  11. Conclusion • If we are to prevent damage to HNW equipment we need: • Adequate resistibility of equipment • Special resistibility of equipment, when the equipment can not be controlled the installation environment. • Correct classification and use of ports • Good installation practices • Correct earthing and bonding • Protection for external and internal ports as necessary. TTC WorkShop

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