CN210894645U

CN210894645U - Fault alarm device

Info

Publication number: CN210894645U
Application number: CN201920902764.8U
Authority: CN
Inventors: 王丹丹; 齐永忠; 王国松; 高振伟; 杨夏祎; 薛青山; 张玉; 孟祥强
Original assignee: State Grid Corp of China SGCC; State Grid Information and Telecommunication Co Ltd; Beijing Guodiantong Network Technology Co Ltd
Current assignee: State Grid Corp of China SGCC; State Grid Information and Telecommunication Co Ltd; Beijing Guodiantong Network Technology Co Ltd
Priority date: 2019-06-14
Filing date: 2019-06-14
Publication date: 2020-06-30
Anticipated expiration: 2029-06-14

Abstract

The utility model discloses a fault alarm device of a power distribution terminal, which comprises a sampling resistor and a detection circuit, wherein the sampling resistor detects the fault current in the circuit; a transistor connected to the sampling resistor, and turned on or off according to a voltage drop of the sampling resistor; and the alarm part is connected to the transistor and used for waking up and sending an alarm signal outwards when the on or off of the transistor is detected. According to the technical scheme of the utility model, MCU's calculation process and calculated amount have been simplified, the consumption can be effectively reduced.

Description

Fault alarm device

Technical Field

The utility model relates to a trouble alarm device that is used for trouble to report an emergency and ask for help or increased vigilance that can use at distribution terminal equipment particularly.

Background

A 10kV distribution line at the end of the grid in the transmission of electricity enables an efficient connection between the transmission network and the end user. One of the main functions of the intelligent power distribution terminal equipment is fault warning and remote transmission. Because of the immediacy of the alarm message, the message must be communicated to the primary station immediately upon detection of the fault.

The existing awakening mechanism for the intelligent power distribution terminal mainly depends on MCU programming. Under the low-power-consumption working mode of the MCU, the device always starts the metering data cache and performs various mathematical calculations to obtain an actual value. And at the moment of the fault, the MCU program design detects the instantaneous current mutation of the distribution line fault, the true value is calculated and compared with the fault judgment criterion, and whether the distribution line has the fault or not is judged. If the judgment result is yes, immediately waking up the MCU to enable the equipment to enter a normal operation mode from a sleep mode, and remotely transmitting fault alarm information through a wireless communication function.

The disadvantages of the above treatment are: in order to ensure accurate judgment of fault information, software needs to keep high-speed and efficient work in the calculation process, and the data caching speed and the calculation speed are high. This will make MCU's power consumption improve, can reach 1.5 times-2.0 times of the power consumption at ordinary times. The increase in power consumption shortens the life of the device. If the current of the distribution line is small, the normal use of the equipment is directly influenced by the increase of the power consumption.

Under normal conditions (no fault condition), distribution lines current is more than 20A, but full function full speed operation of distribution terminal equipment, and below distribution lines current 20A, intelligent distribution terminal needs low-power consumption operation, practices thrift stand-by power supply's use amount as far as possible. The conventional method can reduce power consumption as much as possible only by means of the MCU, but power consumption is reduced only to a limited extent due to limitations in functions and data calculation processing.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a novel fault warning device. According to the utility model discloses an aspect provides a fault warning device, include: a sampling resistor that detects a fault current in the circuit; a transistor connected to the sampling resistor, and turned on or off according to a voltage drop of the sampling resistor; an alarm unit connected to the transistor for waking up and sending out an alarm signal when the transistor is detected to be turned on or off

According to the technical scheme of the utility model, can save a large amount of fault judgement and the time and the code of calculation, also can reach the low-power consumption requirement and the instantaneity requirement when reporting an emergency and asking for help or increased vigilance.

Drawings

Fig. 1 shows a simplified block circuit diagram according to the working principle of the present invention.

Fig. 2 shows a schematic connection diagram of a fault warning device according to an embodiment of the present invention.

Fig. 3 shows a schematic connection diagram in the case of using an N-channel MOS transistor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings.

According to the technical scheme of the utility model, transient state current characteristic when having utilized the circuit to break down. The working principle of the utility model is described by taking the power distribution equipment as an example below: in power distribution equipment with non-disposable backup power supplies, the backup power supplies need to be charge managed. In the charging process of the standby power supply, the charging current of the standby power supply is strictly controlled for the protection of the standby power supply. The technical scheme of the utility model when can utilize the electric current sudden change on the distribution lines, this characteristics of stand-by power supply's charging current also can the sudden increase, cooperation switch circuit and the general detection of MCU reach awakening equipment and the purpose of reporting an emergency and asking for help or increased vigilance.

Fig. 1 shows a simplified block circuit diagram of the above-described operating principle. Wherein transistor, sampling resistor and MCU have constituted promptly according to the utility model discloses a fault alarm device. Wherein the transistor is selectively turned on/off according to a voltage drop of the sampling resistor, and the MCU is an alarm unit connected to the transistor for waking up and externally sending an alarm signal when the on/off of the transistor is detected

Fig. 2 shows a schematic circuit diagram of the fault warning device. The sampling resistor and the transistor are respectively illustrated as a sampling resistor R1 and an NPN transistor Q2, in which only an MCU port (MCU IO) of the MCU is shown, thereby simplifying the illustration. As shown, the resistor R1 is connected to the backup power source and in parallel between the base and emitter of the NPN transistor, and the collector of the transistor Q2 is connected to the port of the alarm unit MCU (MCU IO).

Referring to fig. 1 and 2, the sampling resistor R1 is used to capture the transient current characteristic of the circuit when the circuit is in failure, specifically, when the circuit is in failure, the charging current of the backup power supply will suddenly increase, and the voltage drop across the sampling resistor R1 will increase, so that the transistor can switch on/off state in response to the transient current characteristic.

The triode can be MMBT5088 with the starting voltage of 0.7V, when the distribution line normally runs, due to the charging management and protection functions of the rechargeable standby power supply, the charging current can be ensured not to suddenly change and stably run below 200mA in a steady state, the triode is in a turn-off state, and the MCU detects that the high level always exists.

When the distribution line has a fault, the current suddenly changes, and due to the influence of transient characteristics, the charging current of the rechargeable standby power supply can be instantaneously increased, and the duration time is 50ms-90 ms. Because the charging current of the rechargeable power supply is increased sharply (the primary side current sudden change value is above 150A), the charging loop current of the backup power supply is affected by the line fault current and is increased to 250mA or even higher. The voltage drop of the sampling resistor will increase suddenly, resulting in instantaneous conduction of the transistor. The MCU detects the instantaneous low level and the duration, thereby awakening the equipment and sending fault alarm remote transmission information according to the detected short-time level change.

When a fault occurs, the MCU detects a low level instead of a high level, which mainly depends on the connection mode of the triode. As shown in fig. 2, the transistor is connected in such a way that the collector is open-circuited, so in this design the transistor is low when conducting. R2 in fig. 2 is a pull-up resistor, and the main role is to connect the pull-up resistor in the open collector connection so as to output a high level to the MCU (during steady state operation). The utility model is not limited herein. The above is the description of the embodiments of the present invention in the scene of a fault, however, in other cases, the device basically works in a steady state, during this steady state period can be guaranteed according to the charging and discharging management of the standby power supply, the transistor in this device is in an off state, i.e. the MCU can detect the high level of this device, during this period, the wake-up mechanism of the device mainly relies on the timing wake-up in the programming.

The resistance of the resistor can be designed according to the current value normally reached by the circuit at the time of failure and the conduction voltage of the transistor. In the above situation, the standby power charging loop current may be affected by the line fault current and increase to 250mA or even higher, so that the voltage across the sampling resistor reaches the triode turn-on voltage of 0.7V. The resistor can therefore take the value 3 omega.

According to the technical scheme of the utility model, when distribution lines normal steady state operation, the triode is in the turn-off state, what MCU detected always is the high level. When the distribution lines broke down, the current sudden change, because the influence of transient state characteristic, stand-by power supply's charging current increased suddenly, and the pressure drop of sampling resistance can increase suddenly, leads to the instantaneous conduction of triode. The MCU detects the instantaneous low level, and whether a fault occurs can be judged through the instantaneous low level, so that the equipment is rapidly awakened, and fault alarm remote transmission information is sent out in time. The technical scheme of the utility model the calculation process and the calculated amount of MCU have been simplified, the consumption can be effectively reduced. Additionally, the utility model discloses the hardware detection circuitry of scheme makes circuit design simple, high-efficient in equipment power supply return circuit.

It should be understood that fig. 2 shows the transistor as a triode for example only, and the present invention is not limited thereto. Other transistors such as N-channel MOS transistors may also be used. Fig. 3 shows a schematic connection diagram in the case of using an N-channel MOS transistor.

As shown in fig. 3, the sampling resistor R8 is 8 Ω, and the value is determined according to the turn-on voltage of the MOS transistor and the abrupt change value of the fault circuit current. The transistor is an N-channel MOS transistor Q4 of IRF110, and the turn-on voltage is 2V. The drain of the transistor is connected to a pull-up resistor R6. When the distribution line normally operates, due to the charging management and protection functions of the rechargeable standby power supply, the charging current can be ensured not to generate sudden change and stably operate below 200mA in a steady state, the transistor IRF110 is in a turn-off state, and the MCU always detects a high level. When a distribution line has a fault, the current suddenly changes, the charging current of the rechargeable standby power supply instantaneously increases due to the influence of transient characteristics, the duration time is 50ms-90ms, the voltage drop of the sampling resistor suddenly increases due to the fact that the charging current of the rechargeable power supply suddenly increases to more than 250mA, the IRF110 is instantaneously switched on, the MCU detects the instantaneous low level and the duration time, the equipment is awakened, and fault alarm remote transmission information is sent out according to the detected short-time level change.

The utility model discloses the transistor that can adopt is not restricted to the above-listed example, as long as transient state characteristic appears under the circumstances that the circuit broke down, and the transistor of selection is mutually supported with sampling resistor, can make the transistor switch on or turn-off under transient state characteristic to it can to lead to input MCU's level to change.

The above-mentioned warning unit MCU may further comprise a time calculation circuit for calculating the duration of the conduction of the transistor. The significance of calculating the duration is to prevent false positives. Too short a duration may simply be the opening and closing of the switch in the line, and too long a duration may increase the load on the line.

The technical solution of the present invention is described above by taking the power distribution device as an example, and those skilled in the art will understand that the solution of the present invention can also be applied to other situations as long as the purpose of waking up the alarm can be realized through the combination of the sampling resistor and the transistor.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

In addition, well known power/ground connections to Integrated Circuit (IC) chips and other components may or may not be shown in the provided figures for simplicity of illustration and discussion, and so as not to obscure the invention. Furthermore, devices may be shown in block diagram form in order to avoid obscuring the invention, and also in view of the fact that specifics with respect to implementation of such block diagram devices are highly dependent upon the platform within which the present invention is to be implemented (i.e., specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the invention, it should be apparent to one skilled in the art that the invention can be practiced without, or with variation of, these specific details. Accordingly, the description is to be regarded as illustrative instead of restrictive.

While the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

The present embodiments are intended to embrace all such alternatives, modifications and variances which fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A fault warning device, comprising:

a sampling resistor that detects a fault current in the circuit;

a transistor connected to the sampling resistor, turned on or off according to a voltage drop of the sampling resistor;

and the alarm component is connected to the transistor and used for waking up and sending an alarm signal outwards when the on or off of the transistor is detected.

2. The fault warning device according to claim 1, wherein the transistor is a triode, the sampling resistor is connected in parallel between a base and an emitter of the triode, and a collector of the triode is connected to the warning part.

3. The fault warning device according to claim 2, wherein a pull-up resistor is connected to the collector of the transistor to provide a high level to the warning element during steady state operation;

the sampling resistor is valued such that, in the event of a fault, the product of the fault current and the resistance of the sampling resistor satisfies the turn-on voltage of the transistor, thereby providing a low level to the alarm component during the fault.

4. The fault warning device according to claim 3, wherein the sampling resistor has a value of 3 ohms.

5. The fault warning device according to claim 1, wherein the transistor is an N-channel MOS transistor, the sampling resistor is connected in parallel between a source and a gate of the MOS transistor, and a drain of the MOS transistor is connected to the warning element.

6. The fault warning device according to claim 1, wherein the warning element further comprises a time calculation circuit for calculating a duration of time the transistor is turned on.

7. The fault warning device of any one of claims 1-6, connected in a power distribution terminal equipment, and the sampling resistor is connected to a backup power source of the power distribution equipment.