CN87207140U

CN87207140U - Nondestructive testing device for nonlinear resistance

Info

Publication number: CN87207140U
Application number: CN 87207140
Authority: CN
Inventors: 王存志
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-04
Filing date: 1987-06-04
Publication date: 1988-03-09

Abstract

The utility model discloses a nondestructive testing device for the discharge capacity of resistance material of a nonlinear semiconductor. The nondestructive testing device is a converting device whose digital (current magnitude) and material structure are uniform. The nondestructive testing device is composed of a unit of measuring contact heads, a current meter and a workbench with simple structure. Each contact head is connected in parallel with the current meter connected in series. A bus is connected with a general meter to form a measuring circuit. The current magnitude measured is calculated and compared and a permissive number value is determined. The nondestructive testing device has convenient detection and high accuracy through the experiment and the calibration for a 400A zinc oxide valve sheet. The nondestructive testing device can be used for the monitoring of technology and the research work for nonlinear material.

Description

Nondestructive testing device for nonlinear resistance

The utility model relates to the fixed resister device that the powder that is used for lightning arrester or granular semiconductor material are formed, and is a kind of non-destructive detecting device to non-linear resistance material discharge capacity.

The Non-Linear Resistance of Semiconductor of sheet (abbreviation valve block) is the main building block of lightning arrester, because its non-linear volt one peace characteristic, for big discharge current (when the large impact electric current passes through lightning arrester), resistance is low, thereby limited the residual voltage on the lightning arrester (electric current when the valve block, the voltage drop on valve block.) to protect the insulation of electrical equipment; Under normal power-frequency voltage, the resistance height, thus limited the amplitude of afterflow.The discharge capacity of valve block indicates the through-current capability of lightning arrester, and promptly in the course of action of lightning arrester, the ability of unlikely damage is the key property of lightning arrester by its various electric currents in tolerance.The valve block of different discharge capacities can be assembled in the lightning arrester of different brackets; Discharge capacity is that the valve block of 400A grade can be used for assembling F10W-110J/300(G.I.S) lightning arrester; The assembling that can be used for FY-110J level Y5W-35/126 a little less than 400A; The assembling that can be used for lightning arresters such as FY-10 of 200A grade.

Valve block is that the dusty material of matrix is made by zinc paste or silit generally, and the oxidation zinc metal sheet has the non-linear and much higher through-flow ability more much better than silit resistor disc.The discharge capacity of valve block depends primarily on the homogeneity that electric current distributes by contact along valve block cross-sectional distribution and voltage, needs determine with the method for test.The IEC99 of International Electrotechnical Commission " AC system valve arrester " and China standard JB487-78 " common valve arrester technical conditions " have made concrete regulation to the discharge capacity test of valve block, its test method is a sampling test, and is as follows for the valve block concrete grammar of 400A:

Valve block is placed on the square wave discharge capacity test board, and test board is a copper plate, then valve block is passed to the square wave current totally 20 times that 2 μ s amplitudes are 400A.Per five centres make a short pause and make slice, thin piece be chilled to room temperature.Be 30 seconds～1 minute the interval time each time in five times.Then be decided to be the 400A grade by afterwards not damaging 20 times as if valve block.If damage the square wave current of then selecting the logical 200A grade of a slice degradation else midway.Its process such as preceding.Even this sheet does not damage after 20 times, the sheet that also cancels is handled.It is about 20 minutes that check takes.This sampling observation method has very big shortcoming.

1. slice, thin piece damages and can not use again, if the valve block of 400A grade is very unfortunate.

2. can't guarantee the accuracy that detects.Reason is as follows: generally be that to get residual voltage higher during sampling observation, a slice that pressure ratio is bigger is done destructive the detection.Its rationale is that residual voltage is higher, and its big bulk resistor of pressure ratio ((V5000A)/(V1mA)) must be big, and this sheet is if can must all can pass through by 20 then whole stoves of 400A square wave.But Shi border Qing Kuang And is non-all so.Because the influence of valve block homogeneous has been ignored in this reasoning.So false retrieval and omission easily.If the lightning arrester that is decided to be the 110KV grade that the valve block that is mixed with the 200A grade in the valve block of 400A grade dispatches from the factory to assembling is the hidden danger of a danger beyond doubt.As if the valve block that is mixed with the 400A grade in the valve block that is decided to be the 200A grade, again a unnecessary economic loss concerning factory.

The purpose of this utility model provides the cannot-harm-detection device of a kind of valve block discharge capacity, and is easy to detect, and the degree of accuracy height not only can be used for the test of various types, also can be used for the research of process monitoring and valve block.

This device is a principle of utilizing parallel circuit, and a plurality of contacts of a voltage by flat connection are applied on each different antimeres of valve block, and contact is divided into several zones to the flow area of whole valve block, and with the contact point of contact be the mid point in every zone.If the physical parameter of valve block and chemical parameters be uniformity all, then the current potential on the each point must equate, otherwise then current potential must not wait, by calculating contrast to potential difference (PD), can learn discontinuity of material, thereby determine whether qualifiedly that the potential difference (PD) value is read by the reometer that is serially connected on the flat connection of the contact circuit on each contact, the valve block plane that contact with contact this moment can not be aluminium-plated, to guarantee not form path between the each point; The bottom surface of valve block is aluminium-plated, and places on the copper coin, to constitute test loop.The measurement of this device is as long as use reometer and contact good contact, the numerical value of reading from ammeter can converse the energising performance of material, it is the inhomogeneity translative mode of a kind of numeral and material structure, measuring contacts is symmetrically distributed, can one group contact detect, also can organize contact more and dwindle the zone step by step and detect.

Accompanying drawing 1 is a schematic diagram of the present utility model.

Accompanying drawing 2 is the distributing position figure of seven detection contact.

Accompanying drawing 3 is a structural drawing of the present utility model, and 1 is cable among the figure, and 2 is insulating sheath, 3 is brazen high-voltage contact, 4 valve blocks for test, 5 pick-up unit bodies for insulation, 6 is support, 7 for compressing the spring of usefulness, 8 backplates for the insulating material making, 9 the leads of drawing for detection contact, 10 is orienting sleeve, 11 is detection contact, and 12 is steel ball.

Below with the 400A zinc oxide valve plate, as embodiment of the present utility model, details are as follows in conjunction with the accompanying drawings with the pick-up unit of 7 contacts.

The valve block of test is can only single face aluminium-plated, during detection, aluminium-plated one side is made progress by (accompanying drawing 3), be close to high-voltage contact 3, not aluminium-plated one faces down, because the elastic force of spring 7 makes the steel ball 12 on the detection contact 11 with valve block excellent contact be arranged, steel ball is the ball that bearing is used, very high precision and hardness are arranged, the cable 1 of high-voltage contact and seven detection contact are drawn lead 9 and are connected into by Fig. 1 and measure the loop, all are connected to a milliammeter on each contact, connect a face amount on the bus and be 2 milliamperes reometer.The body 5 of pick-up unit, sheath 2, support 6, backplate 8 and sheath are all used the manufacturing of insulating material organic glass, the orienting sleeve location that detection contact 11 is made by brass.Primary detection contact 11 as shown in Figure 2, for distributing symmetrically and evenly, so that whole valve block can be divided into 6 equal measurement zones, during measurement if the current value of middle contact less than the mean value of all the other 6 contacts, contact in the middle of then disconnecting, otherwise the current value of middle contact is greater than mean value, then this valve block otherwise processed.If during logical 1 milliampere of electric current, six meter readings are (1) 0.03(2 respectively) 0.14(3) 0.3(4) 0.25(5) 0.22(6) 0.06, during logical 400A electric current, then at the 1/6 π r in (3) number district ²The electric current that flows through in the area is 400A * 0.3=120A, if with the pick-up unit of 4 contacts (3) number district is further detected, to 1/24 π r of four meter reading maximums ²The zone can further be measured, and then can improve measuring accuracy.According to theoretical calculate with by the conclusion of act.std test, can think that the full-scale reading that records of six tables can reach the discharge capacity of 400A grade below 0.20 for the first time.

Because the technological level that the present zinc oxide valve plate of China is made is relatively poor, the valve block capacitance of same stove can differ greatly, when the design arrester, sometimes have to get lower nonuniformity coefficient, adopt device of the present utility model to detect easily every valve block, thereby guaranteed the performance and the chargeability that has improved each valve block of arrester.

Claims

1, non-linear resistance the cannot-harm-detection device, it is with the inhomogeneity pick-up unit of numeral material structure, form by reometer and high-voltage contact, detection contact, it is characterized in that high-voltage contact is a copper coin, detection contact is a plurality of contacts of symmetrical distribution, on each detection contact, all be connected in series a reometer, these reometers are formed a flat connection loop, on bus, be connected in series a total current table again, constitute the metering circuit of measuring the partial current value on each contact, detection contact is symmetrically distributed, and measuring resistance is divided into the zone of several five equilibriums.

2, according to the said non-linear resistance the cannot-harm-detection device of claim 1, it is characterized in that detection contact is by the orienting sleeve positioning and guiding, steel ball is as contact, and with the Collapsible structure of spring compression.