Power Distribution System Design
There are multiple power distribution methods in the power system.
Today, Jiangxi Yikai Electric will introduce five power distribution schemes to you through diagram.
1. The power distribution scheme of single-channel incoming line
The distribution form of the single-inlet is shown in the figure
The power distribution scheme of single-channel incoming line belongs to point distribution scheme, and it is also the simplest distribution scheme.
The single-line power distribution scheme can only provide the lowest level of power supply reliability to the load.
Once the power supply is interrupted, there is no redundant power supply to provide the second power supply.
2.the two-way power distribution plan
The power distribution scheme of the two-way incoming line is shown in the figure
There are two sets of power transformers and two sets of incoming loops in the power distribution scheme of the two-way incoming line.
The two sets of power transformers in the two-line incoming power supply scheme in the figure can be powered individually or in parallel. If the power transformer supplies power alone, a mechanical or electrical closing interlock must be provided between the two incoming switches. When one power supply is interrupted, the system can immediately switch to another power supply, thus improving the reliability of power supply. If the capacity of the power transformer is limited, some loads (three-level load) must be cut off to maintain the continuity of the power supply.
The two-line incoming power supply scheme in the figure adopts automatic transfer switch (ATS) to realize automatic power supply switching.
The three-way incoming power supply scheme in the figure adopts a segment switch to operate the bus in sections. In this scheme, two sets of power transformers can each bear to supply power to the load of this section of the bus; when a power transformer is interrupted, another power transformer can maintain the continuous power supply of the load on the two sections of the bus through the bus disconnector. When the power transformer capacity is not sufficient, it is necessary to cut off some unimportant loads (three-level load).
The four-line incoming power supply scheme in the figure uses ATS to realize the switching between mains and generator power supply.
3. Power supply and distribution plan in key areas
As shown in the figure is a typical example of power supply and distribution plan in key areas.
In the picture, “1 # MNS” consists of two sets of power transformers to form a two-way incoming power supply scheme,.
while the “2 # MNS” system separated from the 1 # MNS system is a single-way incoming power distribution scheme,
and the other way “3 #MNS “system is part 4 of the dual line incoming power supply scheme.
In this typical scheme, the most important loads are on the bus of “3 # MINS”, the system switches the mains and generator power supply through ATS, so the load in the “3 # MNS” system can be reliable in any case Power supply.
4. Ring power supply and distribution plan
The ring power supply and distribution scheme can achieve the most complete power supply reliability.
It can be seen from the figure that the four sets of single-line incoming systems are connected in twos to form a ring-shaped power supply and distribution network.
When there is a power interruption in the incoming line of this section, the bus of this section can always obtain power from one of the two sides of the system.
What you need to pay attention to for the ring-shaped power supply and distribution plan are:
1) If the capacity of the power transformer is limited, part of the load must be cut off before switching the bus tie switch;
2) Rigorous protective matching measures must be set between the line switch and the feed switch and between the line switch and the bus coupling switch in each system;
3) All medium voltage systems supplying power transformers must come from the same power grid.
5. Power distribution scheme constructed with uninterruptible power supply
The Uninteruptible Power System-UPS constructed power distribution scheme is shown in the figure.
The UPS has a battery pack installed inside, and sometimes the battery pack may be external.
When the external power supply is working normally, the external power supply rectifier circuit charges the battery pack inside the UPS,.
At the same time outputs the normal operating voltage to the load through the inverter circuit.
when the external power supply stops supplying power, the external load is completely powered by the battery The battery power supply time depends on the battery capacity from 20min to several hours or longer.
When the UPS itself fails, the bypass channel inside the UPS performs the bypass operation.
In the figure, the two-way incoming power distribution system constructed by the city power and the generator is powered by the ATS switch, while the important load is powered by the UPS.
After this processing, the electrical energy obtained by the important load will not be interrupted at any time.