CN201984107U

CN201984107U - Measuring device of desired short circuit current

Info

Publication number: CN201984107U
Application number: CN 201020676599
Authority: CN
Inventors: 张兴; 吴忠良; 龙基智
Original assignee: Uni Trend Technology China Co Ltd
Priority date: 2010-12-23
Filing date: 2010-12-23
Publication date: 2011-09-21
Anticipated expiration: 2020-12-23

Abstract

The utility model provides a measuring device of desired short circuit current, which respectively samples floating voltage and load voltage with load resistance in two terminal network port in civil power grid system; the next step is processed while the voltage is sampled to detect that the circuit wiring is normal and a line voltage is in the range of measuring voltage; and the floating voltage and the load voltage are respectively transmitted into a high precision simulation attenuator, a filter, a high speed analog digital converter and a singlechip to process calculation of the current value of desired short circuit current. The utility model defines current upper limits of various electric appliances, and prevents an accident of short circuit, inflaming and electric leakage caused by excessive current.

Description

A kind of prospective short circuit current measurement mechanism

Technical field

The utility model belongs to the electrical measurement field, particularly a kind of measurement mechanism of prospective short circuit current.

Background technology

Various electronics and household electrical appliance all need to be inserted in the life provides an alternating voltage to use on the domestic power grid; though all have fuse and short-circuit protector in existing various products and the civilian circuit; but it is then unknown for its specific requirement or demand that whether meets this place; the short-circuit current value of singly-terminal pair port is indeterminate in the network system; and can't determine normally to use the upper current limit of multiple electrical equipment; under misoperation of users or some domestic electric appliances commonly used damage and cause under the situation of the civilian electric line short circuit of power frequency; also can't understand fuse or short-circuit protector and whether can play a protective role, generation of fire etc. is embedded with potential safety hazard.

Summary of the invention

The technical problems to be solved in the utility model provide a kind of can do not use electronic apparatus cause the situation of short circuit next can be in advance the accurate device of the short-circuit current value of two ends port in the electrical network of measured place.

The measurement mechanism of a kind of prospective short circuit current described in the utility model, it comprises singly-terminal pair port, high-precision analog attenuator, wave filter, high power load resistance, high-speed AD converter, LCD display, input button and the single-chip microcomputer of the domestic power grid system that connects successively, described single-chip microcomputer comprises a working storage, the device repeatedly voltage of singly-terminal pair port of in measuring the no-load voltage process, taking a sample, each through the decay of high-precision analog attenuator, wave filter carry out the undesired signal filtering, high-speed AD converter carries out A/D conversion and temporary to described working storage; Then load the singly-terminal pair port of the extremely described domestic power grid of high power load resistance system, sample described pull-up resistor one-period voltage and deliver to high-precision analog attenuator decay, wave filter and carry out undesired signal filtering, high-speed AD converter and carry out the A/D conversion after, the voltage of gained and the data of working storage are delivered to single-chip microcomputer in the lump and are done software and algorithm process, draw the initial expected short-circuit current value; Repeat each step at last, after repeatedly measuring and calculate many group initial expected short-circuit current values, reject and differ bigger numerical value, and get the mean value of remaining numerical value, be the prospective short circuit current value of gained.

Described pull-up resistor is by the switch of Single-chip Controlling one high-power switch tube, can realize control to the pull-up resistor voltage load time, the size of current of pull-up resistor is about 25A, can make the degree of accuracy of measuring prospective short circuit current higher, also can not make failure protector play protection; Detect the testing circuit wiring in the time of sampled voltage and whether normally reach line voltage whether in the scope of measuring voltage, if wiring is normal and voltage normally then continue to carry out, otherwise forbid measuring and duplicate detection, point out the information of corresponding wiring error or voltage mistake.Described

The beneficial effects of the utility model are: can measure the short-circuit current value of singly-terminal pair port in the domestic power grid system in advance, clearly use the upper current limit of various electrical equipment, prevent that electric current is excessive to cause short circuit because of using, catch fire, mishap such as electric leakage.

Below in conjunction with accompanying drawing and embodiment, the utility model is described in further detail:

Description of drawings

Fig. 1 is the system architecture synoptic diagram of the utility model hardware components;

Fig. 2 is the testing process synoptic diagram of the utility model software section.

Embodiment

The measurement mechanism of prospective short circuit current described in the utility model; as shown in Figure 1; it comprises the singly-terminal pair port of the domestic power grid system that connects successively; the high-precision analog attenuator; wave filter; high-speed AD converter; single-chip microcomputer and LCD display and button; described single-chip microcomputer comprises a working storage; described device also comprises a high power load resistance; behind the voltage of device a plurality of singly-terminal pair ports of sampling in measuring the no-load voltage process; through the high-precision analog attenuator; wave filter and high-speed AD converter conversion are temporary to working storage; with the voltage of measuring high power load resistance gained through the single-chip microcomputer calculation process and export LCD display to and show short-circuit current value; described pull-up resistor is by the switch of Single-chip Controlling one high-power switch tube; realization is to the control of pull-up resistor voltage load time; the size of current that loads this pull-up resistor is about 25A; can make the degree of accuracy of measuring prospective short circuit current higher; simultaneously can not make failure protector play protection, described button may command single-chip microcomputer adjusting to each step yet.

As shown in Figure 2, live wire, zero line, ground wire are inserted in the measuring equipment testing circuit wiring respectively respectively whether normally reach line voltage whether in the scope of measuring voltage, then do not forbid measuring and duplicate detection, point out corresponding error information simultaneously if meet.If meet and then carry out subsequent step, then single-chip microcomputer is through repeatedly sampling, and the value that rejecting numerical value has big difference is also tried to achieve average no-load voltage value Vo, after recording load voltage value V1, by known pull-up resistor R1, can pass through formula R=(Vo-V1)/V1*R1, then can computing try to achieve loop resistance R.Known no-load voltage Vo and the loop resistance value R that tries to achieve, substitution Ohm law formula: I=Vo/R, can try to achieve initial expected short-circuit current value Io, repeat to try to achieve average short-circuit current value I after institute rejects the value that numerical value has big difference in steps, export LCD display demonstration numerical value at last to.

Above utility model embodiment is described only to be most preferred embodiment of the present utility model, and in order to restriction the utility model, all modifications of being done on the utility model basis, replacement or improvement etc. all do not fall in the protection domain of the present utility model.

Claims

1. a prospective short circuit current measurement mechanism is characterized in that, comprises singly-terminal pair port, high-precision analog attenuator, wave filter, high-speed AD converter, LCD display, input button and the single-chip microcomputer of the domestic power grid system that connects successively.

2. prospective short circuit current measurement mechanism according to claim 1 is characterized in that, comprises that also one produces the high power load resistance of load voltage and the working storage of temporary pending data.