CN103926502B - A kind of alternating current-direct current of dc source alters electric detection means - Google Patents

Abstract

The invention provides an AC-DC channeling detection device for a DC power supply, comprising a DC blocking filter, a voltage divider, a true effective value converter, an A/D sampler, an FPGA, and an audible and visual alarm. After the bus is filtered, the AC signal is output to the voltage divider, the voltage divider divides the voltage and outputs to the true RMS converter, the true RMS converter converts and outputs to the A/D sampler, and the A/D sampler outputs after sampling To the FPGA, the sound and light alarm is connected to the FPGA. The detection device can quickly detect whether there is AC or DC crossover in the DC power supply circuit.

Description

A kind of AC-DC cross-current detection device for DC power supply

technical field

The invention relates to an AC/DC crossover detection device, in particular to an AC/DC crossover detection device for a DC power supply.

Background technique

The DC system grounding fault in the power system is a kind of fault that is prone to occur and is very harmful to the power system. Regardless of whether it is positive grounding or negative grounding, in the case of two-point grounding, it may cause protection malfunction or protection refusal to operate, endangering the normal operation of the primary system. Most of the existing DC monitoring devices use the inspection mode, and it takes a long time to complete a detection, and the efficiency is relatively low, and the existing DC online monitoring device only monitors the insulation, but the AC channeling fault in the DC system and the DC Mutual faults cannot be monitored.

Contents of the invention

The object of the present invention is to provide a detection device capable of quickly detecting whether there is AC/DC crossover in the DC power supply circuit.

In order to achieve the above object, the present invention provides an AC-DC channeling detection device for a DC power supply, comprising a DC blocking filter, a voltage divider, a true effective value converter, an A/D sampler, an FPGA, and an acousto-optic alarm. The input end of the DC filter is connected to the DC bus of the DC power supply, the output end of the DC blocking filter is connected to the input end of the voltage divider, and the output end of the voltage divider is connected to the input end of the true RMS converter. The output end of the converter is connected with the input end of the A/D sampler, the output end of the A/D sampler is connected with the signal input end of the FPGA, and the signal output end of the FPGA is connected with the input end of the sound and light alarm.

After the DC bus is filtered by the DC blocking filter, the AC signal is output to the voltage divider, and then the voltage is divided by the voltage divider and then output to the true effective value converter, and then output to the A/D sampling after conversion by the true effective value converter The A/D sampler samples and then outputs to the FPGA, so that the FPGA judges whether there is an AC component based on the sampling result, and if there is an AC component, it sends an alarm signal to the sound and light alarm.

As a further improvement of the present invention, it also includes a constant current signal source, a voltage data collector and an MCU, the output of the constant current signal source is connected to the DC bus of the DC power supply, and the two input terminals of the voltage data collector are respectively connected to the DC power supply The signal input terminal of the MCU is connected with the output terminal of the voltage data collector, the control terminal of the MCU is connected with the input terminal of the constant current signal source, and the signal output terminal of the MCU is connected with the sound and light alarm connected to the input. A constant current signal source is used to inject a DC source into the DC bus, and then the voltage data collector collects two different points on the DC bus, and finally the MCU judges whether there is a DC crossover based on the collected signal. If there is a DC crossover, then Send an alarm signal to an audible and visual alarm.

As a further improvement solution of the present invention, a display screen is also included, and the signal input terminals of the display screen are respectively connected with the signal output terminals of the FPGA and the signal output terminals of the MCU. The monitor is used to display the test results, which is convenient for the test personnel to record the test results on site.

The beneficial effects of the present invention are: (1) the AC component can be quickly and effectively separated from the DC bus, and the AC component is collected, and the FPGA judges whether the AC component has entered. The optical alarm sends out an alarm; (2) The voltage data collector collects two different points on the DC bus, and then the MCU judges whether there is a DC crossover. If there is a DC crossover, the sound and light alarm sends out an alarm ; (3) The monitor is used to display the test results, which is convenient for the test personnel to record the test results on the spot.

Description of drawings

Fig. 1 is the schematic diagram of the AC detection circuit of the present invention;

Fig. 2 is the schematic diagram of the AC/DC detection circuit of the present invention;

Fig. 3 is a schematic diagram of a circuit with a display function of the present invention.

detailed description

As shown in Figure 1, the AC-DC channeling detection device of the DC power supply of the present invention comprises a DC blocking filter, a voltage divider, a true effective value converter, an A/D sampler, an FPGA and an acousto-optic alarm, and a DC blocking filter The input terminal of the filter is connected to the DC bus of the DC power supply, the output terminal of the DC blocking filter is connected to the input terminal of the voltage divider, the output terminal of the voltage divider is connected to the input terminal of the true RMS converter, and the true RMS converter It can accurately convert the AC signal into a DC signal. The output of the true RMS converter is connected to the input of the A/D sampler. The A/D sampler can complete 10,000 samples per second. The A/D sampler The output end is connected with the signal input end of the FPGA, and the signal output end of the FPGA is connected with the input end of the sound and light alarm.

When the detection device is working, the DC blocking filter first filters the signal on the DC bus, filters out the DC component, and only retains the AC component, then outputs the AC signal to the voltage divider, and then the voltage divider After the voltage is divided, it is output to the true effective value converter. The true effective value conversion converts the AC signal into a direct current signal. After the true effective value converter converts, it is output to the A/D sampler, and the A/D sampler is sampled and then output to the FPGA. , and finally the FPGA judges whether there is an AC component in the DC according to the collection results, and if there is an AC component, the sound and light alarm will send out an alarm.

As shown in Figure 2, in order to further determine whether there is a phenomenon of DC signal crossing in the DC bus, the present invention also includes a constant current signal source, a voltage data collector and an MCU, the output terminal of the constant current signal source and the DC power supply The bus is connected, the two input ends of the voltage data collector are respectively connected to two different points on the DC bus of the DC power supply, the signal input end of the MCU is connected to the output end of the voltage data collector, and the control end of the MCU is connected to the constant current signal The input end of the source is connected, and the signal output end of the MCU is connected with the input end of the sound and light alarm.

When the detection device is working, it also uses a constant current signal source to inject a DC source into the DC bus, and then collects two different points on the DC bus through a voltage data collector, and finally the MCU judges whether the received acquisition signal exists. DC mutual channeling, if there is DC mutual channeling, an alarm will be issued by the sound and light alarm.

As shown in Figure 3, in order to further facilitate the detection personnel to carry out on-the-spot recording, the present invention also designs and also includes a display screen, and the signal input end of the display screen is connected with the signal output end of FPGA and the signal output end of MCU respectively. The monitor is used to display the test results in real time, which is convenient for the test personnel to record the test results on site.

Claims (2)

1. a kind of alternating current-direct current of dc source alters electric detection means, it is characterised in that：Including blocking wave filter, divider, really have Valid value converter, A/D samplers, FPGA and audible-visual annunciator, the input of the blocking wave filter and the direct current of dc source Bus is connected, and the output end of the blocking wave filter is connected with the input of divider, and the output end of the divider has with really The input of valid value converter is connected, and the output end of the RMS conversion device is connected with the input of A/D samplers, described The output end of A/D samplers is connected with the signal input part of FPGA, and the signal output part of the FPGA is defeated with audible-visual annunciator Enter end to be connected；Also include constant current signal source, voltage data collector and MCU, the output end and direct current in the constant current signal source The dc bus in source is connected, two inputs of the voltage data collector respectively with the dc bus of dc source on two Individual difference is connected, and the signal input part of the MCU is connected with the output end of voltage data collector, the control end of the MCU Input with constant current signal source is connected, and the signal output part of the MCU is connected with the input of audible-visual annunciator.

2. the alternating current-direct current of dc source according to claim 1 alters electric detection means, it is characterised in that：Also include one to show Display screen, the signal input part of the display screen is connected with the signal output part of FPGA and the signal output part of MCU respectively.