HT instruments PVCHECK - Manual (Page 45)

PVCHECK
EN - 43
6.4.4. Measuring insulation – STRING mode
CAUTION
The maximum current which can be measured by the instrument is 10A.
Before carrying out the measures of Insulation in "STRING" mode,
always ensure that the instrument is connected to ONE STRING and not
more strings in parallel to avoid possible damage of it
1. Position the cursor onto M
 by using the arrow keys
(
,) and confirm with ENTER. The display shows the
screen to the side.
2. Press the ENTER key, activate “Settings” and possibly
change the desired parameters (see § 5.4). The following
parameters are shown on the display:
 Ins. Test  selected test voltage (250, 500 or
1000VDC)
 Ri min  minimum limit threshold for insulation
measurement
 Mode  measuring mode: STRING
 Vtest  real applied test voltage
 Rp  final value of the measurement obtained by the
parallel of Ri(+) e Ri(-) values which is compared with
the Ri min limit by the instrument
  key  access to the second page with the
measured values of VPN, VEP and VEN voltages
15/05/12 15:34:26
I n s . T e s t : 1 0 0 0 V
R l m i n : 1 . 0 M

M o d e : S t r i n g
V t e s t - - - V
R p - - - M

Selection M
 
3. Connect the instrument to the PV module/string being tested and to the main earth
node of the system as shown in . In particular, connect the negative output pole of the
PV field to terminal N and the positive output pole of the PV field to terminal P.
CAPTION:
E: Green
cable
P: Red cable
N: Black cable
1. Unearthed PV module/string
2. Main system earthing
Fig. 12: Instrument connection for insulation measurement in STRING mode
CAUTION
Upon pressing the GO/STOP key, different error messages can be displayed
by the instrument (see § 6.6) and, therefore, the test cannot be started. Check
and eliminate, if possible, the problem causing the error message before going
on with the test.