CN201656548U - A dual-circuit power supply mutual input device that can avoid swaying electricity - Google Patents

Abstract

The utility model discloses a dual-circuit power supply mutual input device capable of avoiding swaying electricity, which includes a working circuit breaker and a spare circuit breaker, the two circuit breakers are respectively connected with the No. The low-voltage output terminals of the transformer are respectively connected to the storage capacitors connected in parallel to form an electric circuit and the intermediate relays No. 1 and No. 2 through a single-phase full-wave rectifier bridge; The positive end of the opening coil of the switch is connected in series with a single-phase half-wave rectification circuit, and the negative end of the opening coil is connected in series with the normally closed contact of the intermediate relay through a switch; the primary sides of the two AC transformers are respectively connected in parallel with a closing circuit, That is, the N terminal of the closing coil of the working circuit breaker is connected to the self-transfer switch through the normally closed contact of the No. 2 intermediate relay, and the N terminal of the closing coil of the standby circuit breaker is connected to the said Connected to the transfer switch.

Description

A dual-circuit power supply mutual input device that can avoid swaying electricity

technical field

The utility model relates to a power switch backup device, in particular to a dual-circuit power mutual input device capable of avoiding electric shock.

Background technique

The power supply system of the converter in the iron and steel plant generally adopts a dual-circuit power supply, one of which is used as the working power supply, and the other is used as the backup power supply. In order to ensure the continuity of smelting, the power supply stability of the converter is required to be high, and the dual-circuit mutual input mode is generally used. , that is, use the voltage loss coil of the circuit breaker to detect the current power supply voltage. When the power supply voltage is less than 15% of the rated voltage (AC 380V), the working circuit breaker is disconnected, and then the backup power circuit breaker is automatically closed to ensure the continuity of power supply. . However, when the power grid is not stable enough and other users on the power grid fail, the voltage of the power grid will fluctuate instantaneously, commonly known as swaying electricity, at this time the above-mentioned system will act immediately. It causes the equipment under the system, such as the frequency converter to alarm, the contactor to release, and the PLC to stop running, etc., which in turn causes the entire system to stop working and hinders the normal production.

Utility model content

The purpose of this utility model is to provide a dual-circuit power supply mutual input device that can avoid swaying electricity, which can effectively avoid the backup power circuit breaker switching phenomenon that occurs when the voltage fluctuates instantaneously, prevent the system from instantaneous power supply interruption, and ensure the continuity of power supply .

The purpose of this utility model is achieved in this way: a dual-circuit power supply mutual investment device that can avoid swaying electricity includes a working circuit breaker and a spare circuit breaker, and the two circuit breakers are respectively connected to the No. 1 incoming power supply and the No. 2 incoming power supply. The low-voltage output ends of the two AC transformers are respectively connected to the storage capacitors connected in parallel to form an electric circuit through a single-phase full-wave rectifier bridge and the intermediate relay No. 1 and No. 2; the primary sides of the two AC transformers are respectively connected in parallel with an opening circuit , that is, the positive ends of the opening coils of the two circuit breakers are connected in series with a single-phase half-wave rectifier circuit, and the negative ends of the opening coils are respectively connected in series with the normally closed contacts of the intermediate relay through switches; the primary sides of the two AC transformers are respectively connected in parallel One closing circuit, that is, the N terminal of the closing coil of the working circuit breaker is connected to the self-transfer switch through the normally closed contact of the No. Point links to each other with said automatic transfer switch.

The device of the utility model mainly solves the problem of false tripping of the original system under the condition of system voltage fluctuation. The design idea is to delay the sending of the trip signal when the system voltage drops instantaneously, so that the system can avoid the moment of voltage fluctuation. The main component is a capacitor, and the characteristics of the capacitor are used to realize this function. The device of the utility model can be applied to all low-voltage double-circuit mutual investment power supply systems, especially the occasions where the grid voltage is not stable enough.

The utility model has the advantages of simple structure and low cost, and can effectively avoid the switching phenomenon of the backup power circuit breaker that occurs when the voltage fluctuates instantaneously, prevents the system from instantaneous power supply interruption, and ensures the continuity of power supply.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing.

Accompanying drawing is the schematic diagram of circuit structure of the utility model.

Detailed ways

A dual-circuit power supply mutual input device that can avoid swaying electricity, as shown in the attached figure, includes a working circuit breaker Q1 and a backup circuit breaker Q2, and the two circuit breakers Q1 and Q2 are respectively connected to the No. 1 incoming power supply and the No. 2 incoming line Power is connected. The low-voltage output ends of the two AC transformers 1T and 2T are respectively connected to the storage capacitors C3 and C4 which are connected in parallel to form an electric circuit through a single-phase full-wave rectifier bridge, and the intermediate relays 1K and 2K of Nos. 1 and 2. The so-called storage capacitors C3 and C4 are adjustable capacitors. The primary sides of the two AC transformers 1T and 2T are connected in parallel with an opening circuit, that is, the positive terminals of the opening coils 1MX and 2MX of the two circuit breakers are connected in series with a single-phase half-wave rectifier circuit, and the negative terminals of the opening coils 1MX and 2MX are connected in series. The terminals are respectively connected in series with the normally closed contacts 1K and 2K of the intermediate relay through switches Q1 and Q2; the primary sides of the two AC transformers 1T and 2T are respectively connected in parallel with a closing circuit, that is, the N terminal of the working circuit breaker closing coil 1XF passes through The normally closed contact 2K of the No. 2 intermediate relay is connected with the self-transfer switch SK, and the N terminal of the closing coil 2XF of the standby circuit breaker is connected with the said self-transfer switch SK through the normally closed contact 1K of the No. 1 intermediate relay.

In the drawings, 1XF and 2XF are the closing coils of the circuit breaker, and 1MX and 2MX are the opening coils of the circuit breaker. The opening coil MX is changed from the original AC 220V power supply to DC 110V power supply;

D1, D2, D3, and D4 are diodes, C1, C2, C3, and C4 are electrolytic capacitors, and D1, D3, and C2 form a single-phase half-wave rectifier circuit for the opening circuit of No. 2 power supply, composed of D2, D4, and C1 Single-phase half-wave rectification circuit, used for the opening circuit of No. 1 power supply;

1T and 2T are AC transformers, which convert AC 220V into AC 20V, and the AC transformers respectively rectify AC 20V into DC 19V through single-phase full-wave rectifier bridges, which are used to charge capacitors C3 and C4;

1K and 2K are DC 24V intermediate relays, and the auxiliary contacts of 1K and 2K realize mutual switching under automatic state;

SK is a self-injection transfer switch, which is used for manual and automatic switching of the device. When manual is selected, all circuit breakers are manually operated. When automatic is selected, the device can realize automatic mutual switching.

The working principle of the utility model device: as shown in the accompanying drawings, when the selection switch is selected as automatic, the power supply No. 1 is the working power supply, the circuit breaker Q1 is in the closing state, and the circuit breaker Q2 is in the opening state:

①When the working power supply voltage is lower than 185V momentarily, the circuit breaker of the original system will trip immediately and switch to the standby power supply, but the device of the present utility model will not trip immediately at this time, because the capacitor C3 stores electric energy, C3 and 1K A circuit is formed so that 1K will not be released for 2-3.5 seconds, thereby achieving the purpose of avoiding this momentary low voltage.

② When the working power supply loses power, C3 discharges 1K, and when the voltage across C3 is lower than 25% (18V) of the rated voltage of intermediate relay 1K, 1K releases, and at this time 1K normally closed auxiliary contact and opening coil 1MX It forms a loop with the capacitor C1, and the electric energy of the capacitor C1 causes the opening coil 1MX to work with electricity, thereby tripping the circuit breaker Q1.

③ After the circuit breaker Q1 trips, another normally closed auxiliary contact of 1K, the closing coil 2XF and the switch B2 form a circuit, thereby completing the automatic closing of the circuit breaker Q2.

④ When the No. 2 power supply is the working power supply, the working principle is the same, and the action sequence is reversed.

Claims (2)

1. A dual-circuit power supply mutual input device capable of avoiding swaying electricity, including a working circuit breaker and a backup circuit breaker, is characterized in that: two circuit breakers are respectively connected to No. 1 incoming power supply and No. 2 incoming power supply, and two The low-voltage output terminals of the AC transformer are respectively connected to the storage capacitors connected in parallel to form an electric circuit and the intermediate relay No. 1 and No. 2 through a single-phase full-wave rectifier bridge; The positive end of the opening coil of the circuit breaker is connected in series with a single-phase half-wave rectifier circuit, and the negative end of the opening coil is connected in series with the normally closed contact of the intermediate relay through a switch; the primary sides of the two AC transformers are respectively connected in parallel with a closing circuit , that is, the N terminal of the closing coil of the working circuit breaker is connected to the self-transfer switch through the normally closed contact of the No. 2 intermediate relay, and the N terminal of the standby circuit breaker closing coil is connected to the said The self-injection transfer switch is connected. 2. The dual-circuit power mutual input device capable of avoiding swaying electricity according to claim 1, characterized in that: said storage capacitor is an adjustable capacitor.

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