7/28/2019 Ted Spooner
1/35
1
ATRAA Professional Development DayMay 2011
Ted Spooner :
Chair EL42 Co-convenor of TC82 WG3 on Systems
Member of WG6 on Balance of Systems Comp
Standards &
PV Earthing
7/28/2019 Ted Spooner
2/35
STANDARDS - National
AS/NZS5033 revised and will be out for publiccomment mid May. Committee meeting end of July
to discuss comments
AS/NZS4777.1 revised will be out for publiccomment probably June.
AS/NZS4777.2 still being revised.
7/28/2019 Ted Spooner
3/35
STANDARDS- International
MOST IMPORTANT DEVELOPMENTS
International version of 5033 is now out for public
comment internationally.
Inverter safety standard IEC62109-2 will bepublished 2ndhalf of 2011
7/28/2019 Ted Spooner
4/35
Most important short termSAFETY developments
INVERTER SAFETY Standard
Paired with PV Installation Standard
7/28/2019 Ted Spooner
5/35
Inverter safety 62109-2
Protection against electric shock
Floating & Functionally grounded arrays
Additional requirements for stand-alone
inverters
Protection against fire hazards
Inverter backfeed current onto the array
Audible noise
Fault Indication and ALARM
+ many more fine details
7/28/2019 Ted Spooner
6/35
Why do we earth?
To provide bonding of the metal frame of a system toground so that a dangerous voltage is not achieved.
To allow fault currents to flow if an earth fault occurs
somewhere in the system. To provide shielding ie to allow a path for leakage
currents to flow.
To prevent a system floating to a dangerous voltage
that may be undefined.
Where particularly required for equipment or
operational reasons. i.e. Functional Earthing.
7/28/2019 Ted Spooner
7/35
Functional Earthing
+
-
+
-
+
Isolated
Isolated
7/28/2019 Ted Spooner
8/35
Protection against electric shock
IEC Standard - IEC 61140
Protection against electric shock Commonaspects for installation and equipment
&
AS/NZS 3000
7/28/2019 Ted Spooner
9/35
Fundamental rule of protectionagainst electric shock
Hazardous-live-parts shall not be accessible
and accessible conductive parts shall not be
hazardous live
either undernormal conditions with no faultsOR
undersingle-fault conditions
7/28/2019 Ted Spooner
10/35
Protection
under normal conditions is provided by basic
protection.
E.g. Basic insulation, barriers, limitation of Voltage and
or current etc. under single-fault conditionsby fault protection.
E.g. Earthing exposed metal &
Overcurrent protection or other means of detection
Enhanced protective provisions provide protection
under both conditions.
Eg double insulation...Class II.
Provides SAFETYFacilitates Detection
Action taken to removethreat
7/28/2019 Ted Spooner
11/35
7/28/2019 Ted Spooner
12/35
7/28/2019 Ted Spooner
13/35
7/28/2019 Ted Spooner
14/35
7/28/2019 Ted Spooner
15/35
InvertersIsolation/separation
Inverters used for grid connected systems
with LV d.c. Inputs are only required to
have simple separation between the a.c
and the d.c sides.
So
A single fault condition can connect the a.c
to the d.c.
7/28/2019 Ted Spooner
16/35
7/28/2019 Ted Spooner
17/35
7/28/2019 Ted Spooner
18/35
7/28/2019 Ted Spooner
19/35
7/28/2019 Ted Spooner
20/35
7/28/2019 Ted Spooner
21/35
7/28/2019 Ted Spooner
22/35
7/28/2019 Ted Spooner
23/35
TRANSFORMERLESS
ie non separated
Array grounding -> Ungrounded
Array ground insulation
resistance measurement
Test before Startup
If Fault disconnect andalarm
Array residual current
detection
Either RCD on a.c
Prescribed by inverter manufOr
Leakage detection on array
inside inverter
If Fault- shutdown & alarm
7/28/2019 Ted Spooner
24/35
7/28/2019 Ted Spooner
25/35
7/28/2019 Ted Spooner
26/35
7/28/2019 Ted Spooner
27/35
Functionally Earthed PV Generator
- Resistance Earth connection.
Re > Voc/0.030A
-
+
-
+
Isolated
Isolated
-
+
Isolated
A
N
ERe
1st Fault
2nd
Fault
Earthing of the module frames enables the inverter
to detect module faults. ie detect a first fault.
7/28/2019 Ted Spooner
28/35
7/28/2019 Ted Spooner
29/35
+
-
+
Isolated
A
N
EEarth FaultInterrupter
EFIs are not foolproof
1st
Fault
2nd
Fault
What if?
7/28/2019 Ted Spooner
30/35
7/28/2019 Ted Spooner
31/35
7/28/2019 Ted Spooner
32/35
Earthing
Installation and inverter safety standard
need to be brought into play together as
they have complementary functions to
improve safety.
7/28/2019 Ted Spooner
33/35
7/28/2019 Ted Spooner
34/35
7/28/2019 Ted Spooner
35/35
QUESTIONS
Let them have it!
I am home in bed.