Safety Protection. Vertiv NetSure 801 CAA

short-circuit protection. PD380/630AFH-A-Y1 AC distribution cabinet is not supposed to be directly connected to the secondary side of a transformer with capacity greater than 1000kVA. An extra distribution cabinet should be used between PD380/630AFH-A-Y1 AC distribution cabinet and the transformer for short-circuit protection.

2. Generator

If the load of the power supply system is more than 50% of the generator capacity, when the higher harmonic current generated by the rectifiers passes the stator winding of the synchronous generator, the voltage waveform will be severely distorted, which will have two effects. One is, it will cause unstable running and mechanical vibration of the generator; and the other is, the harmonic current will make the generator overheat, thus accelerating the insulation ageing of the generator. This is not only harmful to the generator, but also affects the stable running of the power supply system. Therefore, the load of the power supply system should not exceed 50% of the generator capacity. It should be calculated based on the apparent power. A simple calculation of the generator capacity is: output voltage (taken as 60V) × output current (take the final configuration) × 2.

The power factor and excitation model of the generator should also be taken into consideration when selecting a generator. Brushless generator of fundamental wave excitation model should be used with caution.

Safety Protection

Lightning protection & surge protection

The lightning protection and earthing system of telecom stations should comply with relevant standards.

The power supply system is equipped with a Class- C SPD. To achieve better surge protection, it is recommended to mount Class-B SPD before the AC mains is connected to the system. The mounting of Class-B SPD is shown in Figure 20 .

Class-B SPD should be purchased and mounted by the user. If condition permits, it is recommended that the cable length between the Class-B SPD and the AC distribution unit of the power supply system range between 5 ～ 10m. And this section of cable should be routed indoors to avoid direct lightning strike. When mounting the Class-B SPD, attention should be paid to the sectional area and length of the cable connecting the Class-B SPD: the sectional area should be no less than 25mm 2 , the cable should be as short as possible, and so is the earth cable of the Class-B SPD. The SPDs should be inspected periodically to ensure their normal operation.

Figure 20: Diagram of SPD mounting & system earthing

Vertiv | NetSure 801 CAA Series Power Supply System Instruction Manual 33