Low-voltage automatic switch real-time loop closing detection circuit and control device

Abstract

The utility model discloses a low-voltage automatic switch real-time loop closing detection circuit and a control device, the low-voltage automatic switch real-time loop closing detection circuit comprises a processor with an ARM architecture and a voltage sampling circuit, the voltage sampling circuit is connected to the processor, the voltage sampling circuit comprises a voltage mutual inductance circuit, an operational amplifier conditioning circuit and a filter circuit, the power input end of the voltage mutual inductance circuit is connected with alternating-current phase voltage, the output end of the voltage mutual inductance circuit is connected with the operational amplifier conditioning circuit, the output end of the operational amplifier conditioning circuit is connected with the filter circuit, the processor carries out sampling through 32 points of each cycle, and an effective value and a phase value of voltage are obtained through Fourier calculation according to obtained sampling values. The real-time loop closing detection circuit for the low-voltage automatic switch detects voltage values and phases on two sides of the switch in real time, when requirements are met, relay contact signals are output, the contact is connected into a switch closing loop in series, closing is enabled if the relay contact is closed, or closing is forbidden.

Description

Technical Field

[0001] This utility model relates to power grid distribution automation, specifically to a real-time loop-closing detection circuit and control device for low-voltage automatic switches. Background Technology

[0002] Currently, before closing low-voltage automatic switches in distribution rooms / stations, manual phase sequence testing using specialized equipment is required to prevent malfunctions due to inconsistent phase sequences. However, under the current power grid operation model, power companies often outsource maintenance and installation work to third-party companies. Many uncertain factors can lead to incorrect phase sequence connections, posing significant safety risks.

[0003] Deactivating power before restoring it inevitably results in a brief power outage for users, disrupting their continuous power supply and potentially damaging their equipment. Furthermore, after power restoration or maintenance, there may be an error in the phase sequence on both sides of the switch; directly restoring power in this case could lead to an accident.

[0004] In view of this, it is necessary to improve the traditional loop detection operation mode. Utility Model Content

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a real-time loop-closing detection circuit and control device for low-voltage automatic switches. The purpose of designing this loop-closing detection circuit is to achieve uninterrupted load transfer and prevent accidents after power restoration or maintenance.

[0006] To solve the above technical problems, this utility model provides the following solution: A low-voltage automatic switch real-time loop closing detection circuit of this utility model includes:

[0007] Processors with ARM architecture;

[0008] A voltage sampling circuit is connected to the processor. The voltage sampling circuit includes a voltage transformer circuit, an operational amplifier conditioning circuit, and a filter circuit. The input terminal of the voltage transformer circuit is connected to the AC phase voltage, and its output terminal is connected to the operational amplifier conditioning circuit. The output terminal of the operational amplifier conditioning circuit is connected to the filter circuit. The processor samples 32 points per cycle, and the obtained sample values ​​are used to calculate the effective value and phase value of the voltage according to Fourier transform.

[0009] Furthermore, the processor is a microcontroller, specifically an STM32F051.

[0010] Furthermore, the voltage transformer circuit includes six inductors, which are divided into two groups. Each group of inductors is connected to a three-phase power supply, and a current-limiting resistor is connected to the circuit in which the input terminal 1 of any inductor is connected.

[0011] Each inductor's output terminal is connected to a set of operational amplifier conditioning circuits;

[0012] In a circuit combining an inductor and a set of operational amplifier conditioning circuits, the operational amplifier conditioning circuits include:

[0013] An operational amplifier, wherein the inverting input terminal of the operational amplifier is connected to the voltage output terminal of the inductor, the non-inverting input terminal of the operational amplifier is connected to the VREF terminal of the inductor output terminal, and the output terminal of the operational amplifier is connected to the voltage input terminal of the filter circuit;

[0014] A first resistor is connected in the circuit between the inverting input terminal and the output terminal of the operational amplifier.

[0015] Furthermore, the filter circuit is an RC filter circuit, which is connected one-to-one with the operational amplifier conditioning circuit.

[0016] Furthermore, the low-voltage automatic switch real-time loop closing detection circuit also includes a normally closed contact output relay, which is connected to the processor and controlled by the processor.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] 1. The real-time closing detection circuit of the low-voltage automatic switch of this utility model detects the voltage value and phase on both sides of the switch in real time. When the requirements are met, it outputs a relay contact signal. This contact is connected in series in the switch closing circuit. If the relay contact is closed, closing is enabled; otherwise, closing is prohibited.

[0019] 2. The present invention uses Fourier transform to calculate the effective value and phase value of the voltage from the voltage signals collected on both sides of the low-voltage automatic switch. Attached Figure Description

[0020] Figure 1 This is a block diagram of the real-time loop-closing detection circuit for the low-voltage automatic switch of this utility model.

[0021] Figure 2 This is the circuit diagram of the processor of this utility model.

[0022] Figure 3 This is the circuit diagram of the voltage mutual inductor of this utility model.

[0023] Figure 4 This is the circuit diagram of the operational amplifier conditioning circuit of this utility model.

[0024] Figure 5 This is the circuit diagram of the filter circuit of this utility model.

[0025] Figure 6 This is a circuit diagram of a filter circuit connected to 3.3V in this utility model.

[0026] Figure 7 This is the circuit diagram of the normally closed contact output relay of this utility model.

[0027] The attached diagram is labeled: Voltage sampling circuit 1. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments, so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present utility model. Obviously, the embodiments described in this utility model are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0029] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0030] Example 1: The specific structure of this utility model is as follows:

[0031] Please refer to the appendix. Figure 1-7 The present invention relates to a low-voltage automatic switch real-time loop-closing detection circuit, which includes a processor with an ARM architecture and a voltage sampling circuit.

[0032] The processor is a microcontroller, specifically an STM32F051. The low-voltage automatic switch real-time loop-closing detection circuit also includes a normally closed contact output relay, which is connected to and controlled by the processor.

[0033] A voltage sampling circuit 1 is connected to the processor. This voltage sampling circuit 1 includes a voltage transformer circuit, an operational amplifier conditioning circuit, and a filter circuit. The input terminal of the voltage transformer circuit is connected to the AC phase voltage, and its output terminal is connected to the operational amplifier conditioning circuit. The output terminal of the operational amplifier conditioning circuit is connected to the filter circuit. The processor samples 32 points per cycle, and the obtained sample values ​​are used to calculate the effective value and phase value of the voltage using Fourier transform. The low-voltage automatic switch real-time loop-closing detection circuit of this invention detects the voltage and phase values ​​on both sides of the switch in real time. When the requirements are met, a relay contact signal is output. This contact is connected in series in the switch closing circuit. If the relay contact is closed, closing is enabled; otherwise, closing is prohibited.

[0034] The voltage transformer circuit includes six inductors, which are divided into two groups. Each group of inductors is connected to a three-phase power supply, which is an AC 220V input power supply. A current-limiting resistor is connected to the circuit in which the input terminal (pin 1) of any inductor is connected. Figure 3 The resistors R301, R302, R303, R304, R305, and R306 shown are all current-limiting resistors, and the inductor is used to isolate the circuit.

[0035] Each inductor's output terminal is connected to a set of operational amplifier conditioning circuits;

[0036] In a circuit combining an inductor and a set of operational amplifier conditioning circuits, the operational amplifier conditioning circuits include:

[0037] An operational amplifier, wherein the inverting input terminal of the operational amplifier is connected to the voltage output terminal of the inductor, the non-inverting input terminal of the operational amplifier is connected to the VREF terminal of the inductor output terminal, and the output terminal of the operational amplifier is connected to the voltage input terminal of the filter circuit;

[0038] A first resistor is connected in the circuit between the inverting input terminal and the output terminal of the operational amplifier.

[0039] The filter circuit is an RC filter circuit, which is connected one-to-one with the operational amplifier conditioning circuit.

[0040] like Figure 3-4 As shown, the inverting input of operational amplifier U30A is connected to the V2 output of inductor T302, and the non-inverting input of operational amplifier U30A is connected to the VREF output of inductor T302. Operational amplifier U30A has a power supply pin, which is connected to a 3.3V voltage. A resistor R311 is connected between the inverting input and the output of operational amplifier U30A.

[0041] The inverting input of operational amplifier U301D is connected to the V4 output of inductor T304, and the non-inverting input of operational amplifier U301D is connected to the VREF output of inductor T304. A resistor R313 is connected between the inverting input and the output of operational amplifier U301D.

[0042] The inverting input of operational amplifier U301C is connected to the V3 output of inductor T303, and the non-inverting input of operational amplifier U301C is connected to the VREF output of inductor T303. A resistor R312 is connected between the inverting input and the output of operational amplifier U301C.

[0043] The inverting input of operational amplifier U301B is connected to the V1 output of inductor T301, and the non-inverting input of operational amplifier U301B is connected to the VREF output of inductor T301. A resistor R310 is connected between the inverting input and the output of operational amplifier U301B.

[0044] The inverting input of operational amplifier U302B is connected to the V6 output of inductor T306, and the non-inverting input of operational amplifier U302B is connected to the VREF output of inductor T306. A resistor R315 is connected between the inverting input and the output of operational amplifier U302B.

[0045] The inverting input of operational amplifier U302A is connected to the V5 output of inductor T305, and the non-inverting input is connected to the VREF output of inductor T305. A resistor R314 is connected between the inverting input and the output of operational amplifier U302A. Operational amplifier U302A has a power supply pin connected to a 3.3V voltage.

[0046] The inverting input and output of operational amplifier U302C are interconnected and connected to... Figure 5 The VREF pin of the last filter circuit is connected to the non-inverting input of operational amplifier U302C, which is connected to a 1.5V REF voltage. Figure 6 The circuit consists of capacitor C305, which is connected in parallel with a polarized capacitor C308 and a resistor R317. The positive terminal of the polarized capacitor C308 is connected to the REF 1.5V voltage terminal, and the positive terminal of the polarized capacitor C308 is also connected to resistor R316, the other end of which is connected to a 3.3V voltage. The output terminal of operational amplifier U302C is connected to capacitor C306, which is connected in parallel with a polarized capacitor C307. The positive terminal of polarized capacitor C307 is connected to the output terminal of operational amplifier U302C, and its negative terminal is grounded (DGND).

[0047] like Figure 7As shown, the normally closed contact output relay is connected to a diode D401. The anode of diode D401 is connected to pin DO1 of the processor, and its cathode is connected to voltage D5V. This diode is connected in parallel between pin 3 and pin 4 of the normally closed contact output relay. The real-time loop-closing detection circuit for the low-voltage automatic switch of this invention is connected to a phase voltage of AC 220V. After passing through a current-limiting resistor, it is isolated by a voltage transformer, then passes through an operational amplifier conditioning circuit and a filter circuit. The processor performs 32-point sampling per cycle, and the sampled values ​​are used to calculate the effective value and phase of the voltage using Fourier transform. The processor calculates the effective value and phase of the voltage on both sides of the switch using Fourier transform for the collected voltage signals on both sides of the switch. The processor monitors the voltage and phase on both sides of the switch in real time. When the requirements are met, it outputs a relay contact signal. This contact is connected in series in the switch closing circuit. If the relay contact is closed, closing is enabled; otherwise, closing is prohibited.

[0048] Example 2:

[0049] A control device includes the low-voltage automatic switch real-time loop-closing detection circuit of Embodiment 1.

[0050] In summary, the real-time loop-closing detection circuit of this utility model for low-voltage automatic switches detects the voltage and phase values ​​on both sides of the switch in real time. When the requirements are met, it outputs a relay contact signal. This contact is connected in series in the switch closing circuit. If the relay contact is closed, closing is enabled; otherwise, closing is prohibited. This utility model uses Fourier transform to calculate the effective value and phase value of the voltage from the collected voltage signals on both sides of the low-voltage automatic switch.

[0051] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the contents of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. A real-time loop-closing detection circuit for a low-voltage automatic switch, characterized in that, include: Processors with ARM architecture; A voltage sampling circuit (1) is connected to the processor. The voltage sampling circuit (1) includes a voltage inductance circuit, an operational amplifier conditioning circuit, and a filter circuit. The input terminal of the voltage inductance circuit is connected to the AC phase voltage, and its output terminal is connected to the operational amplifier conditioning circuit. The output terminal of the operational amplifier conditioning circuit is connected to the filter circuit. The processor samples 32 points per cycle, and the sampled values ​​are used to calculate the effective value and phase value of the voltage according to Fourier transform.

2. The low-voltage automatic switch real-time loop closing detection circuit according to claim 1, characterized in that, The processor is a microcontroller, specifically an STM32F051.

3. The low-voltage automatic switch real-time loop closing detection circuit according to claim 2, characterized in that, The voltage transformer circuit includes six inductors, which are divided into two groups. Each group of inductors is connected to a three-phase power supply, and a current-limiting resistor is connected to the circuit connected to the input terminal 1 of any inductor. Each inductor's output terminal is connected to a set of operational amplifier conditioning circuits; In a circuit combining an inductor and a set of operational amplifier conditioning circuits, the operational amplifier conditioning circuits include: An operational amplifier, wherein the inverting input terminal of the operational amplifier is connected to the voltage output terminal of the inductor, the non-inverting input terminal of the operational amplifier is connected to the VREF terminal of the inductor output terminal, and the output terminal of the operational amplifier is connected to the voltage input terminal of the filter circuit; A first resistor is connected in the circuit between the inverting input terminal and the output terminal of the operational amplifier.

4. The low-voltage automatic switch real-time loop closing detection circuit according to claim 1, characterized in that, The filter circuit is an RC filter circuit, which is connected one-to-one with the operational amplifier conditioning circuit.

5. The low-voltage automatic switch real-time loop closing detection circuit according to claim 1, characterized in that, The low-voltage automatic switch real-time loop closing detection circuit also includes a normally closed contact output relay, which is connected to the processor and controlled by the processor.

6. A control device, characterized in that, Includes the low-voltage automatic switch real-time loop closing detection circuit as described in any one of claims 1-5.

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