1 Over view
1.1 Introduction
Forming a complete set with 3G mobile exchange and NGN equipments made by Huawei
Technologies, DPDF-L-I-1300(S) DC distribution cabinet, which has the same structure with the
NGN equipment, and can support cabinet juxtaposition installation, is used for the distribution of -48V
DC power source and the connection of earth line and protective earth line.
The cabinet is non-forced cooling, the working input voltage is -36 ~ -60V, The cabinet uses the
positive bus-bar ear thing mode and the DC dual-power source input/output mode that enables
mutual backup function. The rated input current is 1300A each route, thus, the load can work
normally when any branch-circuit of its power sources has short-circuit or other faults. The total
output is dual 20 routes, among which 100A output is dual 6 routes, 63A output is dual 14 routes. The
cabinet can be extended by replacing breaker, the maximum expansion capability is that 100A output
is dual 15 routes and 63A output is dual 5 routes (The peak power is less than 50KW after the
maximum expansion).
1.2 Model explanation
DPDF :DC Power Distribution Frame
1.3 Structure of DC distribution cabinet
1.3.1 Structure of DC distribution cabinet
DC distribution cabinet is consisting of cabinet, one monitoring subrack and four DC
distribution subrack, the configuration as show following table 1.
1.4 Theory
Formed by main circuit and monitor circuit, DPDF-L-I-1300(S) distribution cabinet realizes the
function of distributing the current to each branch-circuit load.
1.4.1 The theory of main circuit
The theory of main circuit is shown in Figure 1-4.
Two 48V DC power sources (named -48V1 and -48V2, or power supply 1 and power supply 2)
are introduced into the system through DC input positive busbar and DC input negative busbars,
among them, the negative busbars use distributed input and output to reduce the cross sectional
area of busbar.
The power supply was introduced to each breaker through branch busbars to realize the current
distribution. Each 48V DC power supply was divided into 20 routes output, the 6 routes are 100A
output, 14routes are 63A output. The breaker configuration are: first row 1~6 route uses 100A
breaker, 7~10 route uses 63A breaker. Second row 11-16 route uses 100A breaker, 17~20
route uses 63A breaker, third row 21~30 route uses 63A breaker, fourth row 31~40 route uses
63A breaker.
The protection ground line of power source is connected to the PGND ground busbar inside the
cabinet, so do the protective earth of each load equipment.
System positive and negative busbars are connected with the light arrestor respectively and its
PGND is connected with the ear thing busbar, which can provide the lightning protection.
When connecting the load with dual-power source, it should be connected withpower supply
-48V1 and -48V2 respectively, thus the failure of one branch circuit won't affect the normal
operation of load.
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