阅读说明：本技术 线路负载及故障检测装置及方法 (Line load and fault detection device and method ) 是由 何金波 何金涛 肖洁 于 2019-10-22 设计创作，主要内容包括：本发明涉及一种线路负载及故障检测装置,主要包括单片机、正弦信号发生器、采样电路、多路转换电路、有效值转换电路、A/D转换电路,蜂鸣器报警装置和液晶显示器构成,单片机连接蜂鸣器报警装置和液晶显示器,单片机还连接多路转换电路,多路转换电路连接采样电路和有效值转换电路,采样电路连接正弦信号发生器,有效值转换电路连接A/D转换电路,A/D转换电路连接单片机。本发明能实时检测负载电压判断负载开路、短路故障并进行报警,能准确的自动测量电阻电容电感值,并稳定显示,相对误差小于%5,测量时间不大于5s。(The invention relates to a line load and fault detection device, which mainly comprises a single chip microcomputer, a sinusoidal signal generator, a sampling circuit, a multi-path conversion circuit, an effective value conversion circuit and an A/D conversion circuit, wherein the buzzer alarm device and a liquid crystal display are formed, the single chip microcomputer is connected with the buzzer alarm device and the liquid crystal display, the single chip microcomputer is also connected with the multi-path conversion circuit, the multi-path conversion circuit is connected with the sampling circuit and the effective value conversion circuit, the sampling circuit is connected with the sinusoidal signal generator, the effective value conversion circuit is connected with the A/D conversion circuit, and the A/D conversion circuit is connected with the single chip microcomputer. The invention can detect the load voltage in real time, judge the open circuit and short circuit faults of the load and give an alarm, can accurately and automatically measure the inductance value of the resistor and the capacitor, stably display the inductance value, and has the relative error less than 5 percent and the measurement time not more than 5 seconds.)

1. the line load and fault detection device is characterized by comprising a single chip microcomputer, a sinusoidal signal generator, a sampling circuit, a multi-way conversion circuit, an effective value conversion circuit, an A/D conversion circuit, a buzzer alarm device and a liquid crystal display, wherein the single chip microcomputer is connected with the buzzer alarm device and the liquid crystal display, and is also connected with the multi-way conversion circuit, the multi-way conversion circuit is connected with the sampling circuit and the effective value conversion circuit, the sampling circuit is connected with the sinusoidal signal generator, the effective value conversion circuit is connected with the A/D conversion circuit, and the A/D conversion circuit is connected with the single chip microcomputer.

2. The line load and fault detection device of claim 1, wherein the single chip microcomputer employs an STC8592RC chip.

3. The line load and fault detection device of claim 1, wherein said a/D conversion circuit employs a PCF8591A/D analog-to-digital conversion module.

4. the line load and fault detection device of claim 1, wherein said sinusoidal signal generator employs an AD8950DDS device.

5. The line load and fault detection device according to claim 1, wherein the effective value conversion circuit employs an AD637 rectification effective value conversion module.

6. the line load and fault detection device of claim 1, wherein said multiplexing circuit employs an ICL7650 high precision operational amplifier.

7. The line load and fault detection method is characterized in that: the line load and fault detection device according to any one of claims 1 to 6, wherein for fault detection, the device is mainly driven by a power supply, and then voltage sampling is performed on a load to be detected, and for load detection, signals with different frequencies are mainly generated by an AD8950DDS device, and the generated frequencies are controlled by the single chip, voltage sampling is performed on the load to be detected after ICL7650 high-precision operational amplifier and AD637 rectification, namely effective value conversion, and then the voltage sampling is transmitted to the single chip through a PCF85 8591A/D analog-to-digital conversion module, and then the single chip performs logic operation data processing, and the value of an element to be detected is displayed through an LCD1602 liquid crystal screen.

8. If the sampled voltage is 5V, the circuit is broken, if the sampled voltage is 0V, the short circuit is indicated, both the two conditions can give an alarm, and for the measurement of the load, the value of the component can be obtained through corresponding conversion by adopting a voltage proportion method.

9. the line load and fault detection method of claim 7, wherein: the single chip microcomputer controls to generate continuous sine waves with different frequencies, and the process of voltage stabilization, voltage rising and voltage falling is adopted to automatically judge which of the resistor, the inductor and the capacitor belongs to.

10. The line load and fault detection method of claim 7, wherein: the voltage is sampled by the sampling circuit, then the PCF8591A/D analog-to-digital conversion module is used for transmitting the voltage value to the single chip microcomputer, the single chip microcomputer judges the voltage, so that the fault judgment is made and displayed on the LCD1602, and if the fault is short-circuited or broken, the buzzer alarm device simultaneously sends out a buzzer alarm.

Technical Field

the invention belongs to the technical field of power grid line monitoring, and relates to a line load and fault detection device based on single chip microcomputer intelligent control, which is particularly applied to a low-voltage and medium-voltage stabilized power supply circuit, wherein a main implementation module and an electric power part comprise a sampling circuit consisting of an ICL7650 high-precision operational amplifier and an AD637 rectification effective value conversion module, a PCF85 8591A/D analog-to-digital conversion module, an STC8952RC type single chip microcomputer and the like, and the related technical field mainly comprises a single chip microcomputer control technology, a digital electric processing technology, a modular electric processing technology and the like.

Background

At present, a domestic fault indicator needs to be strictly verified to indicate the location of a fault for maintenance personnel, power supply of a fault-free section can be timely recovered, a large amount of working time can be saved, the power failure time and the power failure range can be reduced, a special line fault detection device does not exist, generally, the fault indicator is simply detected by controlling the on-off of a 220V or 380V line according to the load, detailed indexes such as specific value action, duration action and the like of the fault detector cannot be tested, and only manual operation can be performed.

Disclosure of Invention

The invention aims to provide a line load and fault detection device with high automation degree, which can be installed in a circuit controlled by a low-voltage and medium-voltage-stabilizing source and is used for indicating a fault current path. Once the line is short-circuited, the buzzer alarms, and the line patrol personnel can quickly determine the fault section, branch and fault point by means of red alarm display on the indicator. The device changes the laggard method of blind line searching and fault section searching in the past, has higher reliability and instantaneity, and greatly improves the efficiency and the safety.

The technical scheme adopted by the invention is as follows: a line load and fault detection device mainly comprises a single chip microcomputer, a sinusoidal signal generator, a sampling circuit, a multi-way conversion circuit, an effective value conversion circuit, an A/D conversion circuit and a buzzer alarm device and a liquid crystal display.

Further, the singlechip adopts an STC8592RC chip.

Further, the liquid crystal display adopts an LCD1602 liquid crystal screen.

Further, the A/D conversion circuit adopts a PCF8591A/D analog-to-digital conversion module.

Furthermore, the sinusoidal signal generator adopts an AD8950DDS device, and generates a sinusoidal signal with adjustable frequency by the AD8950 DDS.

Further, the effective value conversion circuit adopts an AD637 rectification effective value conversion module.

Further, the multiplexing circuit adopts an ICL7650 high-precision operational amplifier.

The invention also discloses a line load and fault detection method, which comprises the following steps: for the fault detection, the power supply is mainly used for driving, voltage sampling is carried out on a load to be detected, for the load detection, signals with different frequencies are mainly generated by an AD8950DDS device, the generated frequencies are controlled by a single chip microcomputer, the voltage sampling is carried out on the load to be detected after ICL7650 high-precision operational amplifier and AD637 rectification, namely effective value conversion, the voltage sampling is transmitted to the single chip microcomputer through a PCF85 8591A/D analog-to-digital conversion module, then the single chip microcomputer carries out logic operation data processing, and the value of an element to be detected is displayed through an LCD1602 liquid crystal screen. If the sampled voltage is 5V, the circuit is broken, if the sampled voltage is 0V, the short circuit is indicated, both the two conditions can give an alarm, and for the measurement of the load, the value of the component can be obtained through corresponding conversion by adopting a voltage proportion method.

The invention has the advantages that:

firstly, the inductance value of the resistor and the capacitor is accurately and automatically measured and stably displayed, the relative error is less than 5 percent, the measurement time is not more than 5s, the time cost is greatly saved, and the efficiency is improved;

Secondly, a singlechip is used for controlling the DDS to generate a sinusoidal signal;

And thirdly, automatically identifying the type of the inductance and the capacitance through the amplitude-frequency characteristic of the inductance and the capacitance.

Drawings

FIG. 1 is a diagram of the system operating principle;

FIG. 2 is a schematic diagram of an analog-to-digital conversion module of PCF8591 AD;

FIG. 3 is a schematic diagram of a multiplexing circuit, a significance conversion circuit;

FIG. 4 is a schematic diagram of a sinusoidal signal generating circuit;

FIG. 5 is a schematic diagram of a fault detection alarm circuit;

FIG. 6 is a flow chart of alarm module programming;

Fig. 7 is a measurement element work flow diagram.

Detailed Description

for the sake of understanding, the present invention will be explained in further detail below with reference to the drawings and examples.

The structure of the line load and fault detection device is shown in figure 1, and mainly comprises a single chip microcomputer, a sinusoidal signal generator, a sampling circuit, a multi-way conversion circuit, an effective value conversion circuit, an A/D conversion circuit, a buzzer alarm device and a liquid crystal display, wherein the single chip microcomputer is connected with the buzzer alarm device and the liquid crystal display, and is also connected with the multi-way conversion circuit, the multi-way conversion circuit is connected with the sampling circuit and the effective value conversion circuit, the sampling circuit is connected with the sinusoidal signal generator, the effective value conversion circuit is connected with the A/D conversion circuit, and the A/D conversion circuit is connected with the single chip microcomputer.

The singlechip adopts STC8592RC chip, and the LCD adopts LCD1602 LCD screen.

the A/D conversion circuit adopts PCF8591A/D analog-to-digital conversion module, as shown in FIG. 2.

The sinusoidal signal generator adopts an AD8950DDS device, and generates a sinusoidal signal with adjustable frequency by the AD8950DDS, and the circuit principle is shown in figure 4. As shown in fig. 3, the effective value conversion circuit uses an AD637 rectification effective value conversion module, and the multiplexing circuit uses an ICL7650 high-precision operational amplifier. The sampling part is formed by the effective value conversion circuit, the multi-way conversion circuit and the sampling resistor of the sampling circuit.

the main process of line load and fault detection is as follows: for the fault detection, the power supply is mainly used for driving, voltage sampling is carried out on a load to be detected, for the load detection, signals with different frequencies are mainly generated by an AD8950DDS device, the generated frequencies are controlled by a single chip microcomputer, the voltage sampling is carried out on the load to be detected after ICL7650 high-precision operational amplifier and AD637 rectification, namely effective value conversion, the voltage sampling is transmitted to the single chip microcomputer through a PCF85 8591A/D analog-to-digital conversion module, then the single chip microcomputer carries out logic operation data processing, and the value of an element to be detected is displayed through an LCD1602 liquid crystal screen. If the sampled voltage is 5V, the circuit is broken, if the sampled voltage is 0V, the short circuit is indicated, both the two conditions can give an alarm, and for the measurement of the load, the value of the component can be obtained through corresponding conversion by adopting a voltage proportion method.

The fault alarming process comprises the following steps: the voltage is sampled by a sampling circuit, and then the voltage value is transmitted to the single chip microcomputer by using a PCF8591A/D analog-to-digital conversion module. The single chip microcomputer judges the voltage, so that the fault judgment is made and displayed on the LCD1602 liquid crystal screen. If short circuit or open circuit occurs, the buzzer alarm device will sound a buzzer to alarm, as shown in fig. 6.

The process of measuring the element value is as follows: the whole thought is that the voltage proportion is adopted to measure the resistance, the capacitance and the inductance, and the main principle is as follows: measuring the resistance R electrically_XA DC voltage is added in a series circuit with a standard resistor R, and the voltage U sampled to the resistor to be measured by an AD converter_RXthe theoretical calculation formula is as follows:

When measuring inductance and electric capacity, because they are reactance components, so I need add sinusoidal alternating current signal to measure, also we adopt the voltage ratio method, wherein the calculation process of electric capacity is:

w＝2πf，

thus we can get:

the inductance calculation process is as follows:

X_L=jwL

thus, we obtain:

Wherein, w-angular frequency;

X_C-a capacitive reactance;

X_L-an inductive reactance;

C-capacitance;

L-inductance.

the inductance capacitance value can be measured according to the frequency f of a DDS sine generation signal, but automatic detection is required according to the description, so that the type of a load can be judged before measurement, a single chip microcomputer can be used for controlling to generate continuous sine waves with different frequencies, and the resistance, the inductance and the capacitance can be automatically judged according to the frequency characteristics of different loads, the stability, the rise and the fall of the voltage.

The line load and fault detection device is mainly powered by a 5V stabilized voltage power supply, an AD8950DDS generates a sinusoidal signal with adjustable frequency, a sampling circuit consisting of an ICL7650 high-precision operational amplifier and an AD637 rectification effective value conversion module is used, a PCF85 8591A/D analog-to-digital conversion module sends a sampled voltage value to an STC8952RC type single chip microcomputer for logic operation data processing, the voltage value is displayed by an LCD1602 liquid crystal screen, the load voltage can be detected in real time to judge the open circuit and short circuit fault of the load and give an alarm, the inductance value of a resistor and a capacitor can be accurately and automatically measured, the resistance and the capacitance can be stably displayed, the relative error is less than 5%, and the measurement time is not more.

The above is only a preferred embodiment of the present invention, and all simple changes in the spirit of the present invention fall within the protection scope of the present invention.