Connection Procedure - CanadianSolar CSI-75K-T40001-E User Manual

5 Electrical Connection
transformer is connected to to the IT grid, to-groundwithstanding voltage of the LV winding of the transformer, the AC
cables, and the secondary equipment (including the relay protection device, detection & measuring device, and other
related auxiliary devices) should not be lower than 1,100V.
4) The line-to-line voltage on the HV side of transformer should comply with local power grid voltage.
5) A transformer with a tap changer on the HV side is recommended in order to keep consistent with the grid voltage.
6) At an ambient temperature of 45℃, the transformer can run in 1.1 times of load for long time.
7) Transformer with a short-circuit impedance 6% (permissible tolerance: ±10%) is recommended.
8) The voltage drop of system cable is no more than 3%.
9) The DC component that the transformer can withstand is 1% of the fundamental current at rated power.
10) For thermal rating, the load curve of the transformer and environment conditions should be taken into account.
11) The apparent power of the inverter should never exceed the power of the transformer. The maximum AC current of
all inverters connected in parallel must be taken into account. If more than 25 inverters are connected to the grid,
contact CSI Solar.
12) The transformer must be protected against overloading and short circuit.
13) The transformer is an important part of grid-connected PV generation system. The fault tolerance capacity of the
transformer should be taken into account at all times.
The fault include: system short circuit, grounding fault, voltage drop, etc.
14) Take ambient temperature, relative humidity, altitude, air quality, and other environmental conditions into account
when selecting and installing the transformer.
15) When the anti-PID function is enabled, observe the following items:
- If the LV side winding is in Y shape, neutral point grounding is prohibited.
- Surge protective devices (SPD) for the AC combiner box and on the LV side of the transformer are recommended to be
connected in the "3 +1" manner, as shown in the figure below. The Min. continuous operating voltages of M1-M4 are
460VAC.
- The LV side winding of the transformer, AC cables, and secondary devices (- including protective relay, detection and
measurement instruments, and related auxiliary devices) must withstand the voltage to ground of at least 1,000V.
Ensure that the selected terminal can directly contact with the copper bar.
If there are any problems, contact the manufacturer of terminal.
NOTICE Direct contact between the copper bar and the aluminium cable will cause electrochemical corrosion
and impair the reliability of electrical connection.

5.5.2 Connection Procedure

Step 1: Open the wiring compartment.
Step 2: Pull out four plastic rivets on the protection plate, then remove the protection plate.
Step 3: Disconnect the AC-side circuit breaker and prevent it from inadvertent reconnection.
Step 4: Loosen the swivel nut of the AC waterproof connector and select a seal rings according to the cable outer
diameter. Lead the cable through the swivel nut, seal rings, and wiring terminal successively.
Step 5: Strip the protection layer and insulation layer by specific length, as described in the figure below.
FIG 5-16 Anti-PID function connection diagram
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