Symptom
In a OptiX OSN 6800 cabinet, there are four subracks. The DC power distribution box of the cabinet provides four power supplies.
After hardware installation, perform a power switch test in the working and protection power supplies: First perform a power switch test in the DC power distribution box first. Shut down the four working switches in area A of the DC power distribution box. The four switches are the working power supply switches of the four subracks. In this case, the power supply to subracks is normal. Turn on the four switches in area A and shut down the four switches in area B. The four switches in area B are the protection power supply switches of the four subracks. In this case, the power supply to subracks is normal.
Then, perform a power switch test in the working and protection power supplies in the centralized power distribution cabinet. Turn on the two protection power supply switches and shut down the two working power supply switches. In this case, the two lower subracks endure a power failure. Turn on the two working power supply switches and shut down the two protection power supply switches. In this case, the two upper subracks endure a power failure.
Cause analysis
The DC power distribution box of the OptiX OSN 6800 cabinet provides four power supplies. For the four inputs, area A and area B are of mutual backup. Each area accesses two external inputs. The two external inputs in area A are the working power supplies. RTN1(+) and NEG1(-) provide the working power supply (working 1) for the two lower subracks. RTN2(+) and NEG2(-) provide the working power supply (working 2) for the two upper subracks. The two external inputs in area B are the protection power supplies. RTN1(+) and NEG1(-) provide the protection power supply (protection 1) for the two lower subracks. RTN2(+) and NEG2(-) provide the protection power supply (protection 2) for the two upper subracks.
After the on-site fault locating, it is found that the hardware engineer introduced a reverse connection mistake in the two -48V external power cables of working 2 and protection 1. Terminals in area A are connected to the external input power cables of working 1 and protection 1 and terminals in area B are connected to the external input power cables of working 2 and protection 2. In this case, working 1 and working 2 provide power supplies to the two lower subracks at the same time. Protection 1 and protection 2 provide power supplies to the two upper subracks. Hence, this problem occurs.
Procedure
Re-connect the two -48V power cables of working 2 and protection 1 in the reverse way.
Reference Information
l Precautions for connecting external power cables in the OSN 6800 are as follows: The DC power distribution box of the OSN 6800 is different from that of old products. When each input is 63A, four power inputs are required. The cable connections are as follows: The two inputs in area A are the working power supplies. RTN1(+) and NEG1(-) provide the working power supply (working 1) for the two lower subracks. RTN2(+) and NEG2(-) provide the working power supply (working 2) for the two upper subracks. The two inputs in area B are the protection power supplies. RTN1(+) and NEG1(-) provide the protection power supply (protection 1) for the two lower subracks. RTN2(+) and NEG2(-) provide the protection power supply (protection 2) for the two upper subracks.
l After the equipment is powered on, two working/protection power failure tests must be performed to determine if there is any fault in the cable connections. 1. Perform a power failure test in the DC power distribution box. 2. Perform a power failure test in the centralized power distribution cabinet. After the two tests, we can ensure that there will not be power failure faults in the equipment room and the subracks.
