CN217445082U

CN217445082U - Power distribution protection system

Info

Publication number: CN217445082U
Application number: CN202221449787.6U
Authority: CN
Inventors: 陈美�
Original assignee: Hefei Daohua Energy Technology Co ltd
Current assignee: Hefei Daohua Energy Technology Co ltd
Priority date: 2022-06-10
Filing date: 2022-06-10
Publication date: 2022-09-16
Anticipated expiration: 2032-06-10

Abstract

The utility model relates to a distribution protection technical field specifically is a distribution protection system, and this distribution protection system includes the battery, connect the direct current chopper of battery, connect the two-way inverter of direct current chopper, connect the municipal power grids of inverter, be connected with controllable switch S1 between inverter and the municipal power grids, connect the load of inverter, be connected with controllable switch S2 between inverter and the load, distribution protection system charges for the battery through the municipal power grids, and the municipal power grids supplies power to the load, the utility model discloses relative traditional UPS scheme, the cost is lower, the volume is littleer, only to low pressure, falls the electricity and protects and has still increased overvoltage, harmonic protection, when voltage and harmonic are too high, can reduce and strike the load.

Description

Power distribution protection system

Technical Field

The utility model relates to a circuit safety technical field specifically is a distribution protection system.

Background

As shown in fig. 1, in a conventional power distribution protection system, when a power grid is normal: in the bypass mode, the mains supply switch directly supplies power to the output load through the bypass switch, or in the online mode, the mains supply supplies power to the load through two-stage conversion of an AC/DC alternating current-direct current converter and a DC/AC inverter, and meanwhile, the battery charger supplies power to the battery in a floating charging mode; when the power grid fails, the battery power supplies power to the load through the DC/DC direct current chopper and the DC/AC inverter. The traditional power distribution protection system is expensive in manufacturing cost and large in size, and can be influenced by harmonic waves generated by a circuit when in use, so that voltage instability is caused, and electric appliances at a load end are easily damaged.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a distribution protection system to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above purpose, the utility model provides a following technical scheme: a distribution protection system comprises a battery, a direct current chopper connected with the battery, a bidirectional inverter connected with the direct current chopper, a city power grid connected with the inverter, a controllable switch S connected between the inverter and the city power grid, a load connected with the inverter, and a controllable switch S connected between the inverter and the load, wherein the battery is charged by the distribution protection system through the city power grid, and the city power grid supplies power to the load.

Preferably, the controllable switch S includes a voltage sampling module inside, the voltage sampling module adopts an LM, the voltage sampling module includes a first connection end and a second connection end, the first connection end is connected with the positive terminal of the utility grid, the second connection end is connected with the negative terminal of the utility grid, and controllers are disposed in the controllable switch S and the controllable switch S.

Preferably, the battery is formed by a storage battery pack, the charging state of the battery can work in a constant current/constant power charging mode or a constant voltage charging and floating charging mode, and the storage battery pack implements a synchronous charging mode or a grouping charging mode.

Preferably, the battery discharge state may operate in a constant current/constant voltage discharge mode, and the secondary battery pack implements a synchronous discharge mode or a group discharge mode.

Preferably, the controllable switch S and the controllable switch S may be a relay or one of an IGBT and a thyristor.

Compared with the prior art, the beneficial effects of the utility model are that:

compared with the traditional UPS scheme, the new power distribution protection system omits a front-stage PFC (AC/DC) and a battery charger, and has lower cost and smaller volume;

the novel power distribution protection system has the advantages that the novel power distribution protection system is different from the conventional UPS and only protects low voltage and power failure, overvoltage and harmonic protection is added, when the voltage and the harmonic are too high, the controllable switch S1 can be immediately disconnected, impact on loads is reduced, the novel power distribution protection system is more suitable for application of a new energy power distribution system, and power supply of key loads can be guaranteed to be more reliable.

Drawings

FIG. 1 is a conventional power distribution protection system;

FIG. 2 is a novel power distribution protection system;

fig. 3 illustrates a novel embodiment of a power distribution protection system.

Detailed Description

In order to deepen understanding and understanding of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described and introduced in conjunction with the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and do not limit the embodiments in any way. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

Referring to fig. 1-3, the present invention provides a technical solution: a distribution protection system comprises a battery 1, a direct current chopper 2 connected with the battery 1, a bidirectional inverter 3 connected with the direct current chopper 2, a utility grid 5 connected with the inverter 3, a controllable switch S14 connected between the inverter 3 and the utility grid 5, a load 7 connected with the inverter 3, and a controllable switch S26 connected between the inverter 3 and the load 7, wherein the distribution protection system charges the battery 1 through the utility grid 5, and the utility grid 5 supplies power to the load 7.

The controllable switch S14 internally comprises a voltage sampling module 8, the voltage sampling module 8 adopts LM2596, the voltage sampling module 8 comprises a first connecting end and a second connecting end, the first connecting end is connected with the positive end of the commercial power network 5, the second connecting end is connected with the negative end of the commercial power network 5, controllers are arranged in the controllable switch S14 and the controllable switch S26, the battery 1 is composed of a storage battery 1 group, when one storage battery is damaged, the other storage batteries can normally work to avoid influencing the normal operation of a load circuit, the charging state of the battery 1 can work in a constant current/constant power charging mode or a constant voltage charging and floating charging mode, the storage battery 1 group implements a synchronous charging mode or a grouped charging mode, the discharging state of the battery 1 can work in a constant current/constant voltage discharging mode, the storage battery 1 group implements a synchronous discharging mode or a grouped discharging mode, and the batteries can be protected by adopting the grouped mode, the starting of all batteries is avoided, the batteries can be protected, when the load is large, sufficient power supply can be ensured, and the controllable switch S14 and the controllable switch S26 can be relays or one of IGBTs and thyristors. When the power grid is normal, the controllable switch S1 and the switch S2 are both closed, the load is directly supplied by commercial power or the upper-level power distribution, meanwhile, the power grid charges a battery through DC/AC and bidirectional DC/DC, the DC/AC can work in a stable DC bus voltage working mode, and the DC/DC can work in a constant current/constant power charging mode or a constant voltage charging and floating charging mode according to the charging state of the battery; keeping tracking the amplitude and the phase of the power grid voltage;

when a power grid fault is detected, such as power grid failure, power grid voltage drop, power grid overvoltage or power grid voltage harmonic overtension (for example, the power grid voltage amplitude is greater than 1.1pu or less than 0.9pu and the power grid voltage THD) is 5%), immediately controlling the controllable switch S1 to be switched off, simultaneously converting the DC/AC into an alternating current voltage source output mode (V/f mode), and simultaneously commanding voltage to be the power grid voltage amplitude before the fault and the phase angle of the power grid continuously tracked, so as to reduce the impact of switching on load power supply voltage; the switch S1 is a fast switch, so that the switching process is ensured to be as short as possible, such as within 5ms, and the impact on the load is reduced;

when the grid side voltage V1 is detected to be restored to a normal range (the voltage, the frequency and the THD are in the normal range), the output voltage V2 of the DC/AC is controlled to be synchronous with V1, when the amplitude and the phase difference of V2 and V1 are smaller than set threshold values, the switch S1 is controlled to be closed, meanwhile, the DC/AC is switched back to a constant voltage mode from a V/f mode, and the DC/DC is switched back to a charging mode from a discharging mode.

FIG. 3 is a diagram of an embodiment of the power distribution protection system

When the power grid is normal, one part of the power grid directly supplies power to non-critical loads L11, L12 and L1N through a distribution transformer, the other part of the power grid supplies power to critical loads L21, L22 and L2N (such as a controller, a switch, a data acquisition device, a box transformer measurement and control device and the like), an S1 switch is disconnected after the power grid fault is detected, and the DC/AC only supplies power to L21, L22 and L2N so as to prolong the power supply time; and closing S1 after the synchronization from V2 to V1 is completed by grid voltage recovery, and recovering the power supply of the grid to non-critical loads L11, L12 and L1N and critical loads L21, L22 and L2N.

While embodiments of the present invention have been shown and described, it is emphasized that: the foregoing description is only illustrative of the manner of usage of the embodiments of the present invention and is not intended to limit the invention in any way. It will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A power distribution protection system, characterized by: this distribution protection system includes battery (1), connection direct current chopper (2), the connection of battery (1) bidirectional inverter (3), the connection of direct current chopper (2) the utility grid (5) of inverter (3) be connected with controllable switch S1(4), connection between inverter (3) and the utility grid (5) load (7) of inverter (3) be connected with controllable switch S2(6) between inverter (3) and the load (7), distribution protection system charges for battery (1) through utility grid (5), utility grid (5) are supplied power to load (7).

2. A power distribution protection system according to claim 1, wherein: the controllable switch S1(4) is internally provided with a voltage sampling module (8), the voltage sampling module (8) adopts LM2596, the voltage sampling module (8) comprises a first connecting end and a second connecting end, the first connecting end is connected with the positive end of the commercial power grid (5), the second connecting end is connected with the negative end of the commercial power grid (5), and controllers are arranged in the controllable switch S1(4) and the controllable switch S2 (6).

3. A power distribution protection system according to claim 1, wherein: the battery (1) is composed of a storage battery (1), the charging state of the battery (1) can work in a constant current/constant power charging mode or a constant voltage charging and floating charging mode, and the storage battery (1) implements a synchronous charging mode or a grouping charging mode.

4. A power distribution protection system according to claim 3, wherein: the discharge state of the battery (1) can work in a constant current/constant voltage discharge mode, and the storage battery (1) group implements a synchronous discharge mode or a group discharge mode.

5. A power distribution protection system according to claim 1, wherein: the controllable switch S1(4) and the controllable switch S2(6) may be a relay or one of an IGBT and a thyristor.