Transcript
TR41.7.1-07-08-006-L-PoE-Presentation
Document Cover Sheet
Project Number
NA
Document Title
PoE Presentation
Source Contact
Mick Maytum
Distribution
TR-41.7.1
Intended Purpose of Document (Select one)
XX
For Incorporation Into TIA Publication For Information Other (describe) -
The document to which this cover statement is attached is submitted to a Formulating Group or sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of which provisions are hereby incorporated by reference.
This document is a presentation on Power over Ethernet
Page 1
Power Over Ethernet (POE) What is it? How to Protect it? Michael J Maytum Bourns Limited, UK
[email protected]
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 1 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Abstract Power Over Ethernet (POE) is a relatively new Ethernet variant that provides powering to the terminal equipment similar to POTS. The voltages are similar to POTS, but the current is higher, delivering 13 W of power and newer versions are coming giving around 35 W. All this uses the existing unshielded four twisted pair Ethernet cable. The relatively high powering current means the reach distance is 100 m. Even so that can site a POE active antenna in the building roof where the lightning environment can be quiet severe. The first part of the talk describes Ethernet, how powering is achieved (two ways of cable usage and two types of power supply) and the terminal interface configurations. The IEEE Std. 802.3af voltage withstand requirements are covered. Some likely outcomes of the IEEE Std. 802.3at are discussed. The second part of the talk looks at what is being protected at both interface ports, existing protection offerings in the market and the consequences of applying protection.
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 2 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Contents Basic Ethernet — Cable and pair usage — Port circuits and withstand voltages Power Over Ethernet (POE) — Cable power feed — Port powering POE Protection — IEEE 802 Group Position — What could happen — What needs protecting — Testing surge withstand Questions 2007 PEG Annual Meeting Power Over Ethernet (POE), Page 3 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Basic Ethernet - The cable
Four (4) Twisted Pairs
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 4 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Basic Ethernet - Pair Usage
Only two (2) out of the four (4) twisted pairs for 10 Mb/s and 100 Mb/s systems
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 5 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Basic Ethernet - Port circuits Isolation and Coupling
1
R J- 45
75 Ω
2 3 75 Ω
6 1 nF 2 kV
"Bob Smith" Termination
4 5 7 8
Magnetic components provide isolation and coupling Note the termination circuit 2 kV rated capacitor to ground
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 6 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Basic Ethernet - Port withstand voltages IEEE 802 LAN/MAN Standards Committee - Choice is a byword IEEE 802.3TM-2002 (1538 pages) withstand at least one of the following three longitudinal voltage requirements: 1) 1500 V rms at 50 Hz to 60 Hz for 60 s, applied as specified in Section 5.3.2 of IEC 60950: 1991. 2) 2250 V dc for 60 s, applied as specified in Section 5.3.2 of IEC 60950: 1991. 3) A sequence of ten 2400 V impulses of alternating polarity, applied at intervals of not less than 1 s. The shape of the impulses shall be 1.2/50 µs (1.2 µs virtual front time, 50 µs virtual time of half value), as defined in IEC 60060. Typically the interface transformer has an isolation withstand voltage (Hipot) of 1.5 kV rms and the termination capacitor has a 2 kV rating.
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 7 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE, 802.3af - power feed pairs IEEE 802 LAN/MAN Standards Committee - Choice is a byword PSE
RJ 45 Cable RJ 45 1
PSE
1 Signal Pair
Tx
PD
2 4
RJ 45 Cable RJ 45 1
Rx 2
2
4
4
Spare Pair 5
PD Load 7
Spare Pair
6
7 Spare Pair
8
8
3
3
Signal Pair
Rx
5
VPort
7
3
4
5 PD Load
VPort
8
Rx 2
Spare Pair 5
7
1 Signal Pair
Tx
PD
Tx
3 Signal Pair
Rx
6
8
6
Tx 6
Spare-pair (mode B) and Phantom (Mode A) feed options PD = Powered Device, PSE = Power Sourcing Equipment
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 8 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Power levels PSE
RJ 45 Cable RJ 45 1
PSE
RJ 45 Cable RJ 45
2
4
Rx
4 Spare Pair
2 5
44 V to 57 V < 0.4 A < 15.4 W
2 x 3.5 V @ 0.35 A 2.5 W
36 V to 57 V < 0.36 A < 13 W
44 V to 57 V < 0.4 A < 15.4 W
5
3 6
7 Spare Pair
3 Signal Pair
36 V to 57 V < 0.36 A < 13 W
2 x 3.5 V @ 0.35 A 2.5 W 7
Rx
PD
1 Signal Pair
Tx
PD
Tx
8
8
6 Mode A
Mode B
Power sourced, lost and delivered over 100 m cable
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 9 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - adding to existing systems Non-PSE RJ 45 Cable RJ 45 Hub or Switch 1 1 Signal Pair Tx 2 2 4
Midspan PSE
RJ 45 Cable RJ 45 1
Rx
2
2
4
4 Spare Pair
Spare Pair 5
1 Signal Pair
4 5
5
5 PD Load
VPort 7
7
7
Spare Pair
7 Spare Pair
8
8
8
8
3
3
3
3
Signal Pair
Rx 6
PD
Signal Pair 6
6
Tx 6
Use of Midspan unit to introduce power feed
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 10 of 30, © 2007 Bourns
PEG - Protection Engineers Group
VPort+ VPort-
Enironment A - Common VPort+ Line
Port Interface Circuits Separate low-voltage power distributions
Port Interface Circuits
Single low-voltage power distribution system
POE - Source power supply arrangements
VPort+ VPort-
VPort+ VPort-
Enironment B - Segments Isolated
Environment A: one PSU feeds all ports Environment B: one PSU for each port
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 11 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE Plus - 802.3at Being formulated by the IEEE P802.3at DTE Power Enhancements Task Force. PSE
RJ 45 Cable RJ 45 1
1 Signal Pair
Tx
PD Rx
2
2
4
4 Spare Pair
5
5 PD Load
VPort 7
7 Spare Pair
8
8
3
3 Signal Pair
Rx 6
Tx 6
The aim is to deliver much more power than IEEE Std 802.3af2003, to enable multi band wireless access points and controllable security cameras to be connected. Single and dual feed variants being considered. Based on 802.3af, 2x13 W = 26 W can be delivered. Goal is to deliver something in the 30 W to 50 W range. This requires more current. Main consideration now is cable temperature rise. (liaising with TIA TR42)
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 12 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE Plus - 802.3at surge protection When asked about comprehending surges and surge protection the IEEE P802.3at respondent wrote: The IEEE 802.3 has no mandate to deal with these issues.
Not my job in other words!
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 13 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Not My Job - 1
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 14 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Not My Job - 2
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 15 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What could happen 4 kV Induced voltage
+2 kV
PSE
PD -2 kV
100 m
OK 4 kV Induced voltage
0
PSE
PD -4 kV
100 m SPD
Not OK, transverse surges as well Differential ground potential rise PSE
PD 100 m SPD
SPD
Surges coupled by induction and direct connection Long and short duration surges! Ref. Testing Equipment Internal Line Ports, PEG 2005
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 16 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What needs protecting 1 Signal Interface Isolation and Coupling
1
R J- 45
75 Ω
CDC BLOCK Insulation Breakdown
Transverse Overvoltage
2 3
75 Ω
CDC BLOCK
Overvoltage
1 nF 2 kV
"Bob Smith" Termination
6 4 5 7 8
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 17 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What needs protecting 2 Powered Device, PD, Interface PD RJ 45 PGND
1 Signal Pair
5 µF min
Rx 2
PGND
4
100 V VPORTP rating
Spare Pair 5
VPORTP 100 nF 100 V
100 V rating
SMAJ58A VPORTN
7 8
Tx 6
VPORTN
Power on switch
PGND
Rectifier voltage rating 100 V?
3 Signal Pair
PGND
PGND
VPORTP
Cable
Spare Pair
VOUT
64.4 V min @ 1 mA 93.6 V max @ 4.3 A, 10/1000 121 V max @ 19A, 8/20
PGND PGND
A unidirectional thyristor crowbar would offer better protection
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 18 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What needs protecting 3 Power Sourcing Equipment, PSE, Interface 3.3 V Isolated
64.4 V min @ 1 mA 93.6 V max @ 4.3 A, 10/1000 121 V max @ 19A, 8/20
0V Isolated
100 V rating 100 nF 100 V x4
70 V rating
SMAJ58A x4 0V Isolated
VEE 0V Isolated -48 V Isolated
0.5 Ω
Port 1 120 V rating
0V Isolated
0.5 Ω 120 V rating
Port 2 0.5 Ω 120 V rating
Port 3 0.5 Ω Port 4 120 V rating
A unidirectional thyristor crowbar would offer higher current protection
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 19 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What needs protecting 4 Power Sourcing Equipment, PSE, Interface shows surge back-feed problem 3.3 V Isolated
64.4 V min @ 1 mA 93.6 V max @ 4.3 A, 10/1000 121 V max @ 19A, 8/20
0V Isolated
100 V rating 100 nF 100 V x4
70 V rating
SMAJ58A x4 0V Isolated
VEE 0V Isolated -48 V Isolated
0.5 Ω
Port 1 0.5 Ω
0V Isolated
Port 2 0.5 Ω Port 3 0.5 Ω Port 4
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 20 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE surges - What needs protecting 5 Power Sourcing Equipment, PSE, Interface fix for surge back-feed problem 0V Isolated
0V Isolated
100 nF 100 V
3.3 V Isolated 70 V rating
SMAJ58A VEE
-48 V Isolated
0.5 Ω Port 1
A unidirectional thyristor crowbar would offer higher current protection
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 21 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Current Ethernet SPD offerings Same protection voltage every which way RJ 45
RJ 45
1
1
Signal Pair
Signal Pair 2
2
4
4
Spare Pair
Spare Pair 5
Cable
5
15 V now 60 V
G
7
Cable
7
Spare Pair
Spare Pair 8
8
3
3
Signal Pair
Signal Pair 6
6
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 22 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Current POE SPD offerings Solution only for when spare pair powering is used RJ 45
RJ 45
1
1
Signal Pair
Signal Pair 2
2
4
4
Spare Pair
Spare Pair 5
Cable
60 V
15 V
5
Cable
G
7
7 Spare Pair
Spare Pair 8
8
3
3
Signal Pair
Signal Pair 6
6
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 23 of 30, © 2007 Bourns
PEG - Protection Engineers Group
Possible POE SPD Design Bells, Whistles, Belt and Braces RJ 45
RJ 45
1
1
Signal Pair
Signal Pair 2
2
4
4
Spare Pair
Spare Pair 5
Cable
60V
60V
5
Cable
G
7
7
Spare Pair
Spare Pair 8
8
3
3
Signal Pair
Signal Pair 6
6
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 24 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Testing surge withstand - 1 GR-1089-CORE, Issue 4, clause 4.6.9 First-Level Intra-Building Lightning Surge Tests (Telecommunications Type 2 and 4 Ports) “Intra-building tests are not required if the intra-building wiring (cabling) connects to equipment that is not grounded, does not have any other connection to ground, and has no power ports” = POE PD equipment. Definitions: Telecommunications port applies to equipment that have paired-conductor interfaces in a telecommunications network (such as T and R leads, sleeve leads, E & M leads). For example, 10BaseT and 100BaseT Ethernet and other similar ports are considered telecommunications ports. Telecommunications ports include ports that provide power to remote telecommunications equipment over outside plant telecommunications circuits. DC power port applies to equipment that provides an interface for connection directly to the dc mains. Port AC power port applies to equipment that provides an interface for connection directly to the ac mains.
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 25 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Testing surge withstand - 2 GR-1089-CORE, Issue 4, clause 4.6.9.1 Ports Connected to Unshielded Cables “Transverse surge testing shall only be done on Ethernet ports that have secondary voltage-limiting protection to ground.” This misses the fact that someone could connect an external SPD in the cable!
Two pair (4 wire) ports tested with either 2/10 or a 1.2/50-8/20 generator Transverse ±800V, 100 A, 2/10 Longitudinal ±1500 V, 100 A, 2/10 or Transverse ±800V, 1.2/50, (6 Ω series) 100 A, 3/31 Longitudinal ±1500 V, (10 Ω series) 83 A, 4.7/25
Four pair (8 wire) ports are tested with a 1.2/50-8/20 generator Transverse ±800V, 1.2/50, (6 Ω series) 100 A, 3/31 Longitudinal ±1500 V, (20 Ω series) 43 A, 4.7/25 Table 4-6 covers 1-2, 3-4 and >4 pair test situations. Issue 4 A type test configurations only covers 1-pair and 2-pair interfaces.
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 26 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Testing surge withstand - 3 GR-1089-CORE, Issue 4, Longitudinal and Transverse Test circuits R R Output
R R R
1.250-8/20 Test Generator
R R R
R
EUT
1 2
Output
4 5
EUT
1 2 4 5
7
1.250-8/20 Test Generator
8 3 6
7 8 3 6
E Return
E Return
4 Pair (8 Wire) Longitudinal Test
4 Pair (8 Wire) Wire-Wire Transverse Test
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 27 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Testing surge withstand - 4 GR-1089-CORE, Issue 4, Transverse Test circuit problems R
Output
R
EUT
1
R
2
Output
4 5
1.250-8/20 Test Generator
EUT
1 2 4 5
7
1.250-8/20 Test Generator
8 3 6
7 8 3 6
E Return
E Return
4 Pair (8 Wire) Transverse Test
4 Pair (8 Wire) Pair-Pair Transverse Test
Standard wire-to-wire transverse test does not stress power source or load Need a pair-to-pair transverse test to stress power feed pairs, applied 1-2 to 3-6 and 4-5 to 7-8
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 28 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Suggested Protection Requirements Applications like wireless access points and controllable security cameras are likely to have high levels of coupled surge. Research is needed to establish design withstand levels
Protection Voltage Levels Pair to ground: less than 2 kV Power feed pairs: less than 100 V
Coupled Surges Duration: short (voltage induction) to long (current induction and ground potential rise) Amplitude: 30 % of outside line port. Surge Testing Test Modes: Longitudinal, transverse: wire to wire and power feed pair to power feed pair or let the protection generate the surge Testing: done with any specified external SPD Generator Voltage: 2 kV or more longitudinally
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 29 of 30, © 2007 Bourns
PEG - Protection Engineers Group
POE - Final Comment Don’t forget clause 4.6.17 Second-Level Intra-Building AC Power Fault Tests for Equipment To Be Located on Customer Premises (Type 4 Telecommunications Port) That’s a 120 V rms, 25 A rms longitudinal and transverse test for type 4 ports (customer premises)!
2007 PEG Annual Meeting Power Over Ethernet (POE), Page 30 of 30, © 2007 Bourns
PEG - Protection Engineers Group
