2. EARTHING STANDARDS
EARTHING STANDARDS
Protection against Lightning-
Electrical & Electronic systems
“within” structures- IS / IEC
62305
Scope of Work : Provides information for the DESIGN, INSTALLATION, INSPECTION,
MAINTENANCE & TESTING of LPMS for Electrical & Electronic systems within
a structure, able to the risk of permanent failures due to lightning EM
Impulse.
Not in Scope : This standard does not cover protection against
of electronic systems, which is due to EM interference.
(refer IS/IEC 60364-4-44 & IEC 61000 series)
6. EARTHING STANDARDS
EARTHING STANDARDS
Protection against Lightning-
Electrical & Electronic systems
“within” structures- IS / IEC
62305
The need for this International Standard has arisen due to the
of electrical & electronic system, caused by Electro Magnetic effects of
Lightning. because, milli- joules of
Energy is sufficient to cause damage, whereas lightning flashes releases
Hundreds of mega joules of energy..
11. Office building
Examples of installations in use
1. Class I + II SPD
2. Class II SPD
required for line lengths > 10 m
2. Surge arresters B + C
3. Class III SPD
0
10
1
2
3
4
Sales
Sales
12. (Industrial plant)
Examples of installations in use
1. Class I + II SPD
2. Class II SPD
3. Appliance protection
Class III
15. EARTHING STANDARDS
EARTHING STANDARDS
Connecting Wires
If it is not possible to keep to the recommended line length of ≤ 0.25 m to the
arrester and from the arrester to the earthing point the surge protection
devices should not be connected with a spur line, but in a V-shape.
Take care to run the outgoing and return lines as far apart as possible.
18. EARTHING STANDARDS
EARTHING STANDARDS
SPD Selection Criteria
Voltage Protection level - 'Lower' is better for the connected
equipment
Surge current withstanding capacity
Response of SPD
Encapsulated, non-exhaustive spark gap
Co-ordinated SPD Protection
Compliance to latest IEC standards
22. EARTHING STANDARDS
EARTHING STANDARDS
UPS Protection
UPS is vulnerable to surges due to 3 reasons:
is micro-processor controlled device , the damage of
which prevents changeover to the generator in case of mains power failure.
2. Failure of which run from auto transfer switch to generator (to
start the generator prior to operation of change over switch) leads to “NO
BACK UP SUPPLY” when UPS batteries dry out.
3. Front end of the UPS- is vulnerable to surges
24. EARTHING STANDARDS
EARTHING STANDARDS
Need for SPDs…. Failures reported
in a refinery in Kerala, India
1. Tripping of variable Frequency Drives & other soft starters
2. Failure of Computers (which were off line !!??##)
3. Failure of VHF communication systems
4. Failure of Auto Tank gauging system
5. Failures of gas monitor systems
6. Failure of telephone exchange
7. Failure of palm vane access control reading system
8. Failure of fire alarm systems
9. Failure of I/O cards in Satellite rack rooms
10.Failure of Alarm cards in Gas turbine control panel
11.Communication failure of Hydrocom of MUG compressor
12.Failure of cards in blending system
25. EARTHING STANDARDS
EARTHING STANDARDS
Need for SPDs…. Failures reported
in a major Thermal Power Plant in UP,
India.
1. Card failure in telephone exchange
2. Analog Output (AO) card failure in BMS panel
3. IGBT failure in VFD
4. Thyristor failure in VFD
5. EEPROM corruption in GE Mark V governing system
6. Power supply failure in GE Mark V governing system
7. CPU, AI & Communication card failure in Boiler # 3 panel
8. Power supply & Communication card failure in Ash bund RF
26. EARTHING STANDARDS
EARTHING STANDARDS
Need for SPDs…. Failures reported
in a Spice ingredient plant in Kerala
1. Failure of PLC Power Supply & AO card
2. Failure of EPABX power supply & trunk line
3. Failure of motor break control in automatic flex door
4. Failure of UPS
5. Failure of Weigh bridge LOAD CELLS & DISPLAY
6. Failure of biometric access sensor card
7. Failure of router & Ethernet switches
28. Coupling of systems
A direct strike on a building with an
external lightning protection
installation
L1
L2
L3
PEN
Data line
5% of Iimp is through data lines
5% of Iimp is through data lines
32. EARTHING STANDARDS
EARTHING STANDARDS
Tips for installation
§ Connection as close as possible to the device!
§ Use short wires for the connection!
Conductor length max. 0,5
m
Local earthing
point
Conductor length max. 0,5 m
Local earthing point
§ Connection as close as
possible to the device!
§ Use short wires for the
connection!
Connection to the earthing