CN207586321U - A kind of small-size multifunction electric power parameter tester - Google Patents

Abstract

The utility model is related to a kind of small-size multifunction electric power parameter testers.A kind of small-size multifunction electric power parameter tester, circuit board including housing and enclosure interior, the housing is assembled by head cover and bottom case, the both sides up and down of the head cover are equipped with 16 connecting terminal blocks altogether, and power circuit on the circuit board is housed, microprocessor, difference channel, computation chip, storage chip, communicating circuit, A phase current mutual inductors, C phase current mutual inductors, shares A phase voltages mutual inductor and shared C phase voltages mutual inductor.A kind of small-size multifunction electric power parameter tester of the utility model, using design concepts such as miniaturization, multi-functional, anti-interference and backup batteries, the telemeterings electricity such as the electric current, voltage, active and reactive and electric energy of power unit can be tested, it can achieve the effect that flexibly to be equipped with, facilitate installation, accurately test, preventing interference and steady operation by serial communication with coordinating other remote signalling test equipments and backstage power consuming administrative system.

Description

A kind of small-size multifunction electric power parameter tester

Technical field

The utility model is related to parameters of electric power test equipment fields, are surveyed more particularly to a kind of small-size multifunction parameters of electric power Try instrument.

Background technology

Electric power parameter tester is the instrumentation that electric system carries out electrical energy measurement and electricity consumption monitoring, is widely used in electricity The measurement of gas device fabrication industry and petrochemical industry, Ferrous Metallurgy, railway electrification, research and teaching department to power consumption parameter； With the development of microelectric technique, various digital instruments gradually instead of pointer simulate instrument, therefore, the degree of automation compared with High cabinet-type parameters of electric power test and communication apparatus are using commonplace in large enterprise, and many small business are special It is rural area outlying district, since electrical equipment is few but region is more dispersed, so using large-scale power parametric test equipment just It is less economical, it installs and uses also less flexibly, and since the less stable of power-supply system can also make the unfavorable shadow of pairwise testing It rings.

Utility model content

In order to solve the above technical problems, the utility model provides a kind of small-size multifunction electric power parameter tester, pass through A kind of small electrical parameter testing instrument is designed, using the integrated micro element of most of patch, reduces the volume of complete machine； Working power as internal circuit is inputted using phase three-wire three, the input mode of this redundancy backup power supply can be in external electricity As usual steady operation during the phase shortage of source；Line-hit and test error can effectively be eliminated using three-phase two elements test method；This Tester especially suitable in small-sized industrial enterprise to electric parameter measurement.

Technical solution is used by the utility model solves its technical problem：A kind of small-size multifunction parameters of electric power test Instrument, the circuit board including housing and enclosure interior, the housing are assembled by head cover and bottom case, and up and down the two of the head cover Side is equipped with 16 connecting terminal blocks altogether, equipped with power circuit, microprocessor, first via difference channel, the on the circuit board Two-pass DINSAR circuit, first via computation chip, the second road computation chip, storage chip, communicating circuit, first via A phase currents are mutual Sensor, the second road A phase current mutual inductors, the second road C phase current mutual inductors, shares A phase voltages at first via C phase current mutual inductors Mutual inductor and shared C phase voltages mutual inductor；Three phase mains is converted to DC power supply, the output of the first power supply by the power circuit It holds as microprocessor, first via difference channel, No. second difference channel, first via computation chip, the second road computation chip, storage Chip and communicating circuit power supply, second source output terminal are powered for the isolation outlet side of communicating circuit；The microprocessor Data line connects first via computation chip, the second road computation chip, storage circuit and communicating circuit, first via computation chip respectively Signal wire connect with first via difference channel, the input terminal of first via difference channel connects first via A phase current mutual inductances respectively Device, first via C phase current mutual inductors, the output line for sharing A phase voltages mutual inductor and shared C phase voltages mutual inductor；It counts on the second tunnel The signal wire of amount chip is connect with No. second difference channel, and the input terminal of No. second difference channel connects the second road A phases electricity respectively Current transformer, the second road C phase current mutual inductors, the output line for sharing A phase voltages mutual inductor and shared C phase voltages mutual inductor；Institute State in 16 connecting terminal blocks number one terminal to the inside of No. eight terminal respectively with first via A phase current mutual inductors, The input line connection of C phase current mutual inductors, the second road A phase current mutual inductors, the second road C phase current mutual inductors all the way, described the No. nine terminals are connect to the inside of ride on Bus No. 11 terminal with the input side of power circuit respectively；Tenth No. two terminal is to the tenth Input line of the inside of No. four terminals respectively with shared A phase voltages mutual inductor and shared C phase voltages mutual inductor is connect；The communication A line of the circuit after isolation exports is connect with inside of the B lines respectively with the tenth No. six terminal and the tenth No. five terminal.

The power circuit includes EMC modules, three power conversion modules, three current-sharing modules and direct current shunt module； The three phase mains inlet wire of the input terminal of the power circuit is connected to the input terminal of EMC circuits, three output terminals of the EMC circuits The corresponding input terminal for being connected to three power conversion modules respectively, correspondence is connected to three to the output terminal of three power conversion modules respectively The input terminal of current-sharing module, the output terminal of three current-sharing modules are simultaneously connected into the input terminal being followed by all the way to direct current shunt module, institute It states the two-way direct current power supply of direct current shunt module output two-way electrical isolation and passes through the first power output end and second source is defeated Outlet exports.

The tested two-way power unit of outside connection of the number one terminal to No. eight terminal is used to measure four branches The magnitude of current, wherein, number one terminal and No. second terminal connect the Ia1 current transformers on external first electrical equipment circuit, the No. three terminals and No. four terminal connect the Ic1 current transformers on external first electrical equipment circuit；No. seven terminal and the 8th Number terminal connects the Ia2 current transformers on external second electrical equipment circuit, and No. five terminal and No. six terminal connect external the Ic2 current transformers on two electrical equipment circuits.

Three phase lines being correspondingly connected on the outside of No. nine terminal to ride on Bus No. 11 terminal in three-phase power line.

The tested two-way power unit of outside connection of tenth No. two terminal to the tenth No. four terminal is used to measure two Common voltage amount, wherein, the tenth No. two terminal, the tenth No. three terminal and the tenth No. four terminal are connect on external shared power circuit Uab voltage transformers and Ubc voltage transformers.

The outside of tenth No. five terminal and the tenth No. six terminal is connect with outside RS-485 buses；The RS-485 is total The distal end of line is connected to the distant place communication management apparatus of power department computer room.

On the connecting terminal block wiring is used for equipped with terminal screw；The connecting terminal block is equipped with protection and renovates, and uses Cable connector on security isolation terminal；The protection renovates and is respectively provided with eight wiring holes, and for installing wiring when penetrates Screwdriver tightens terminal screw.

The quadrangle of the head cover is respectively provided with housing matching hole, screwed on head cover in the housing matching hole after mating screw and Bottom case assembling is fixed.

The side of the circuit board is packed into after being fixed on the centre of inside of top cover in bottom case, and the bottom surface two of the bottom case is diagonal On be respectively provided with a mounting hole.

A guide rail installation clamp is additionally provided on the bottom surface side of the bottom case.

The beneficial effects of the utility model：A kind of small-size multifunction electric power parameter tester of the utility model, in The electricity consumption place of small business's particularly rural area outlying district dispersion, using miniaturization, multi-functional, anti-interference and backup battery etc. Design concept provides practical parameters of electric power test and communication apparatus to the Electro-metering of power department, can test electricity consumption The telemeterings electricity such as electric current, voltage, the active and reactive and electric energy of unit, can be by serial communication with other remote signalling is coordinated to test Equipment and backstage power consuming administrative system reach the effect be flexibly equipped with, facilitate installation, accurately test, preventing interference and steady operation Fruit.

Description of the drawings

Fig. 1 is a kind of outline structural diagram of small-size multifunction electric power parameter tester of embodiment；

Fig. 2 is a kind of electrical block diagram of small-size multifunction electric power parameter tester of embodiment；

Fig. 3 is a kind of power circuit schematic diagram of small-size multifunction electric power parameter tester of embodiment；

Fig. 4 is a kind of wiring application schematic diagram of small-size multifunction electric power parameter tester of embodiment.

Specific embodiment

In order to deepen the understanding to the utility model, the utility model is done further below in conjunction with drawings and examples Detailed description, the embodiment are only used for explaining the utility model, and the scope of protection of the utility model is not formed and is limited.

Embodiment

As shown in Figure 1, it is a kind of small-size multifunction electric power parameter tester provided in this embodiment, including housing and electricity Road plate 3, the housing are assembled by head cover 1 and bottom case 2, and the front and rear sides of the head cover are respectively provided with a connecting terminal block 4, The terminal screw 5 for being respectively used for wiring equipped with eight on each connecting terminal block；It is respectively provided on each connecting terminal block Protection renovates 6, for the cable connector on security isolation terminal, operating personnel is avoided to touch；The protection, which is renovated, to be respectively provided with Eight wiring holes 7, for installing wiring when, penetrate screwdriver and tighten terminal screw；The head cover quadrangle is respectively provided with housing matching hole 8, head cover and bottom case assembling are fixed after mating screw 9 is screwed in the housing matching hole；The side of the circuit board passes through company It connects block and Screw is fixed on the centre of inside of top cover, be then charged into bottom case；The electricity of each device blocks on the circuit board Source, input, output and PORT COM are connected by each terminal of conducting wire and connecting terminal block；The bottom surface two of the bottom case is diagonal On be respectively provided with a mounting hole 10, guide rail installation clamp 11 is additionally provided on the bottom surface side of the bottom case, when mounted may be used The present apparatus is fixed in power communication cabinet equipment internal backplane by selection by the mounting hole, can also pass through the guide rail The present apparatus is fixed on the guide rail inside power communication cabinet equipment by clamp.

As shown in Fig. 2, it is a kind of electrical block diagram of small-size multifunction electric power parameter tester of the present embodiment；Electricity All components in road are respectively mounted on circuit boards, equipped with power circuit 3a, microprocessor 3b, the first via on the circuit board Difference channel 3e, No. second difference channel 3f, first via computation chip 3c, the second road computation chip 3d, storage chip 3g, communication Circuit 3h, first via A phase current mutual inductors 3i1, first via C phase current mutual inductors 3i2, the second road A phase current mutual inductors 3j1, the second road C phase current mutual inductors 3j2, A phase voltage mutual inductor 3k1 and shared C phase voltages mutual inductor 3k2 are shared；Power supply electricity No. nine terminal in the input side and connecting terminal block on road 9., No. ten terminal 10. with ride on Bus No. 11 endThree terminals Connection, these three terminals distinguish tri- phase lines of LA, LB, LC in external three-phase power line；First power supply of the power circuit Output terminal 3a81 is respectively to first via difference channel and No. second difference channel, first via computation chip and the second road metering core Piece, microprocessor, storage chip and communicating circuit power supply, second source output terminal 3a82 are exported to the isolation of the communicating circuit Side powers；The data line of the microprocessor connects first via computation chip, the second road computation chip, storage circuit and leads to respectively Interrogate circuit, the signal wire of the first via computation chip connect with first via difference channel, the first via difference channel it is defeated Enter end connection first via A phase current mutual inductors, first via C phase current mutual inductors, shared A phase voltages mutual inductor and shared C respectively The output line of phase voltage mutual inductor；The signal wire of second road computation chip is connect with No. second difference channel, and described second The input terminal of road difference channel connects the second road A phase current mutual inductors, the second road C phase current mutual inductors, shares A phase voltages respectively The output line of mutual inductor and shared C phase voltages mutual inductor；In the connecting terminal block number one terminal 1., No. second terminal 2., Third terminal 3., No. four terminal 4., No. five terminal 5., No. six terminal 6., No. seven terminal 7., No. eight terminal (inside 8. respectively with first via A phase current mutual inductors, first via C phase current mutual inductors, the second road A phase current mutual inductors and The input line of second road C phase current mutual inductors connects, the tenth No. two terminal in the connecting terminal blockTenth No. three terminalWith the tenth No. four terminalInside respectively with the input line of shared A phase voltages mutual inductor and shared C phase voltages mutual inductor connect It connects；The outside connection of number one terminal to No. eight terminal is tested four branches of two-way power unit in the connecting terminal block For measuring the magnitude of current, the tested two-way of outside connection of the tenth No. two terminal to the tenth No. four terminal is used in the connecting terminal block Electric unit is for two common voltage amounts of measurement；In A, B line and connecting terminal block of the communicating circuit after isolation exports Tenth No. six terminalWith the tenth No. five terminalInside connection, the tenth No. six terminal and the tenth in the connecting terminal block The outside of No. five terminals is connect with outside RS-485 buses.

Again as shown in Fig. 2, a kind of circuit of small-size multifunction electric power parameter tester of the present embodiment, using microprocessor as Core is equipped with computation chip, difference channel and electric current and voltage transformer, is detected by the test method of three-phase two element The parameters such as electric current, voltage and the power of two-way three-phase power device；For the test per the load of three-phase three-wire system all the way, every road is only With employing 2 electric currents and 2 voltage transformers, it is possible to for measuring the voltage of threephase load, electric current and active general power； It is that circuit structure is simple using the advantages of three-phase two element test method, high certainty of measurement uses electric loading especially suitable for small-sized Measurement；Microprocessor in circuit is by programming the operation, storage and communication realized to two-way measurement data；Computation chip collection It is surveyed into second order sigma-delta ADC, reference voltage circuit and all power, energy, virtual value, power factor and frequency The circuits such as the Digital Signal Processing of amount can measure the active power of each phase and three-phase, reactive power, apparent energy, active Electric energy and reactive energy, while the parameters such as each phase current, voltage effective value, power factor, phase angle, frequency can also be measured；Difference Circuit can pass through the amplification to two input signals so that it is zero that the interference of two input signals, which is effectively inputted, so as to reach The purpose of suppression common mode interference is arrived；Storage chip can be by all measurement data and address, the baud rate of communication etc. with binary system Form preserves, and preservation data are remained in dead electricity, for microcomputer reads and storage；Communicating circuit can change data-signal Level is communicated into RS-485, and pass through isolation output to prevent the intrusion of external electromagnetic interference.

As shown in figure 3, it is a kind of power circuit schematic diagram of small-size multifunction electric power parameter tester of the present embodiment；Figure In the power circuit include EMC modules 3a1, the first power conversion module 3a2, second source modular converter 3a3, third electricity Source modular converter 3a4, the first current-sharing module 3a5, the second current-sharing module 3a6, third current-sharing module 3a7 and direct current shunt module 3a8；Three phase mains inlet wire LA, LB and LC of the power circuit input terminal are respectively connected to EMC circuit input ends, the EMC electricity Uab, Ubc and Uac of road output terminal are respectively connected to the first power conversion module 3a2, second source modular converter 3a3, third electricity The input terminal of source modular converter 3a4, the first power conversion module 3a2, second source modular converter 3a3, third power supply turn Correspondence is connected to the first current-sharing module 3a5, the second current-sharing module 3a6, third current-sharing module 3a7 to the output terminal of mold changing block 3a4 respectively Input terminal, the first current-sharing module 3a5, the second current-sharing module 3a6, third current-sharing module 3a7 output terminal and be connected into one Road is followed by the input terminal of direct current shunt module, and the two-way direct current power supply of the direct current shunt module output two-way electrical isolation leads to Cross the first power output end 3a81 and second source output terminal 3a82 outputs；EMC modules (the Electro Magnetic Compatibility, electromagnetic compatibility) mainly in the upstream end of power supply to have prevented behind High-frequency Interference or lightning stroke etc. from causing The damage of circuit and the circuit set；Mainly it is made of varistor, capacitance and resistance etc., wherein, the work of capacitance and resistance Be absorb power supply in high-frequency harmonic, the effect of varistor is to prevent surge voltage impact.The characteristic of varistor is it Resistance value change with the variation of applied voltage, when applied voltage is relatively low, substantially obstructed overcurrent, varistor present High-impedance state；When applied voltage is up to or over pressure sensitive voltage, the electric current flowed through increases suddenly, can rapidly let out surge current It puts to greatly；First power conversion module 3a2, second source modular converter 3a3, third power conversion module 3a4 using Width funtion inputs AC/DC conversion circuits, because three groups of input voltages Uab, Ubc and Uac are 380V, therefore the range of Width funtion It is set as AC380V ± 20%, i.e. AC304V to AC456V；First power conversion module 3a2, second source modular converter 3a3, High-voltage ac power is converted into low-voltage direct by third power conversion module 3a4 after over commutation, transformation, decompression, filtering respectively Power supply, the output terminal of this three-way direct current power supply flow mould by the first current-sharing module 3a5, the second current-sharing module 3a6, third respectively D.C. regulated power supply all the way is merged into after block 3a7, the first current-sharing module 3a5, the second current-sharing module 3a6, third flow mould The effect of block 3a7 is to prevent electric current from pouring in down a chimney and playing the role of current balance type；The redundancy backup In-put design of this working power, than Conventional slave station becomes acquisition, and single-phase working power has the advantages of prominent all the way：It powers all the way just as long as having in three-phase input power supply Often, it is ensured that the normal work of this tester；The DC low voltage power supply all the way of input is converted by the direct current shunt module Low-voltage dc power supply that two-way is mutually isolated simultaneously passes through the first power output end 3a81 and second source output terminal 3a82 outputs, The isolation outlet side of middle second source output terminal 3a82 supplies communicating circuit, it is therefore an objective to prevent external communication circuit to internal circuit Interference.

As shown in figure 4, it is a kind of wiring application schematic diagram of small-size multifunction electric power parameter tester of the present embodiment；This Tester in embodiment tests the parameters of electric power of the first electrical equipment 12 and the second electrical equipment 13 when in use；It is installing During wiring, in the connecting terminal block on the head cover, number one terminal and No. second terminal connect 12 line of external first electrical equipment The Ia1 current transformers 15 of road, third terminal and No. four terminal connect the Ic1 electricity on 12 circuit of external first electrical equipment Current transformer 16；No. seven terminal and No. eight terminal connect the Ia2 current transformers 17 on 13 circuit of external second electrical equipment, No. five terminal and No. six terminal connect the Ic2 current transformers 18 on 13 circuit of external second electrical equipment；Tenth No. two end Son, the tenth No. three terminal and the tenth No. four terminal connect the external Uab voltage transformers 19 shared on power circuit and Ubc voltages are mutual Sensor 20；The RS-485 buses of the outer side joint external communications equipment of tenth No. five terminal and the tenth No. six terminal, the RS- The distal end of 485 buses is connected to the distant place communication management apparatus 14 of power department computer room, can also and be connect in RS-485 buses Other parameters of electric power test equipments；Wiring application in this way disperses medium-sized and small enterprises particularly rural area outlying district Electricity consumption place, to the Electro-metering of power department provide it is practical minimize, multi-functional, jamproof parameters of electric power is tested And communication apparatus, achieve the effect that flexible outfit, facilitated installation, accurately test, preventing interference and steady operation.

The application of the present embodiment is only that the telemetering amount of small-scale electrical equipment is detected in electric system, other electricity ginsengs Number and the control signal such as information such as remote signalling, remote pulse, remote control, will also be realized, electric system using dedicated testing and control equipment In by RS-485 bus transfer communication signals when, need to be controlled by computer room distant place communication management apparatus.

A kind of small-size multifunction electric power parameter tester of the present embodiment, the element used are most of for the integrated of patch Micro element reduces the volume of complete machine.

A kind of small-size multifunction electric power parameter tester of the present embodiment, for medium-sized and small enterprises particularly rural area outlyingly Scattered electricity consumption place is distinguished, using design concepts such as miniaturization, multi-functional, anti-interference and backup batteries, to the use of power department Electricity metering provides practical parameters of electric power test and communication apparatus, can test the electric current, voltage, active, nothing of power unit The telemeterings electricity such as work(and electric energy by serial communication and can coordinate other remote signalling test equipments and backstage power consuming administrative system, Achieve the effect that flexibly to be equipped with, facilitate installation, accurately test, preventing interference and steady operation.

Above-described embodiment should not in any way limit the utility model, all by the way of equivalent replacement or equivalency transform The technical solution of acquisition is all fallen in the scope of protection of the utility model.

Claims (10)

1. a kind of small-size multifunction electric power parameter tester, it is characterised in that：It includes housing and the circuit board of enclosure interior, institute It states housing to be assembled by head cover and bottom case, the both sides up and down of the head cover are equipped with 16 connecting terminal blocks, the circuit altogether Equipped with power circuit, microprocessor, first via difference channel, No. second difference channel, first via computation chip, the second tunnel on plate Computation chip, storage chip, communicating circuit, first via A phase current mutual inductors, first via C phase current mutual inductors, the second road A phases Current transformer, shares A phase voltages mutual inductor and shared C phase voltages mutual inductor at the second road C phase current mutual inductors；The power supply Three phase mains is converted to DC power supply by circuit, and the first power output end is microprocessor, first via difference channel, the second tunnel Difference channel, first via computation chip, the second road computation chip, storage chip and communicating circuit power supply, second source output Hold the isolation outlet side power supply for communicating circuit；The data line of the microprocessor connects first via computation chip, second respectively Road computation chip, storage circuit and communicating circuit, the signal wire of first via computation chip are connect with first via difference channel, and first The input terminal of road difference channel connects first via A phase current mutual inductors, first via C phase current mutual inductors, shares A phase voltages respectively The output line of mutual inductor and shared C phase voltages mutual inductor；The signal wire of second road computation chip is connect with No. second difference channel, The input terminal of No. second difference channel connects the second road A phase current mutual inductors, the second road C phase current mutual inductors, shares A phases respectively The output line of voltage transformer and shared C phase voltages mutual inductor；Number one terminal is to the 8th in 16 connecting terminal blocks The inside of number terminal respectively with first via A phase current mutual inductors, first via C phase current mutual inductors, the second road A phase current mutual inductances The input line connection of device, the second road C phase current mutual inductors, No. nine terminal to the inside of ride on Bus No. 11 terminal are electric with power supply respectively Road input side connection, the tenth No. two terminal to the inside of the tenth No. four terminal respectively with shared A phase voltages mutual inductor and shared C The input line connection of phase voltage mutual inductor, A line of the communicating circuit after isolation exports are held with B lines with the tenth No. six respectively Son is connected with the inside of the tenth No. five terminal.

2. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The power circuit Including EMC modules, three power conversion modules, three current-sharing modules and direct current shunt module；The input terminal of the power circuit Three phase mains inlet wire be connected to the input terminals of EMC circuits, correspondence is connected to three power supplys to three output terminals of the EMC circuits respectively The input terminal of modular converter, the output terminals of the three power conversion modules corresponding input terminal for being connected to three current-sharing modules respectively, three The output terminal of a current-sharing module is simultaneously connected into the input terminal being followed by all the way to direct current shunt module, the direct current shunt module output two The two-way direct current power supply of road electrical isolation simultaneously passes through the first power output end and the output of second source output terminal.

3. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The number one end The tested two-way power unit of outside connection of son to No. eight terminal is used to measure four branch current amounts, wherein, number one end Son and No. second terminal connect the Ia1 current transformers on external first electrical equipment circuit, third terminal and No. four terminal Connect the Ic1 current transformers on external first electrical equipment circuit；No. seven terminal and No. eight terminal connect external second electricity consumption Ia2 current transformers on device line, No. five terminal and No. six terminal meet the Ic2 on external second electrical equipment circuit Current transformer.

4. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：No. nine end Three phase lines being correspondingly connected on the outside of son to ride on Bus No. 11 terminal in three-phase power line.

5. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：Described tenth No. two The tested two-way power unit of outside connection of terminal to the tenth No. four terminal is used to measure two common voltage amounts, wherein, the tenth No. two terminals, the tenth No. three terminal and the tenth No. four terminal connect Uab voltage transformers and Ubc electricity on external shared power circuit Press mutual inductor.

6. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：Described tenth No. five The outside of terminal and the tenth No. six terminal is connect with outside RS-485 buses；The distal end of the RS-485 buses is connected to Electricity Department The distant place communication management apparatus in door machine room.

7. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The wire connection terminal On row wiring is used for equipped with terminal screw；The connecting terminal block is equipped with protection and renovates, for the line on security isolation terminal Cable joint；The protection renovates and is respectively provided with eight wiring holes, and for installing wiring when penetrates screwdriver and tightens terminal screw.

8. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The four of the head cover Angle is respectively provided with housing matching hole, fixes head cover and bottom case assembling after mating screw is screwed in the housing matching hole.

9. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The circuit board Side is fixed on behind the centre of inside of top cover and is packed into bottom case, is respectively provided with a mounting hole on the bottom surface two of the bottom case is diagonal.

10. a kind of small-size multifunction electric power parameter tester according to claim 1, it is characterised in that：The bottom case A guide rail installation clamp is additionally provided on the side of bottom surface.