Eight-terminal voltammetry measuring method of direct current resistance
Technical field
The present invention relates to a kind of measuring method of direct current resistance, specifically, relate to a kind of eight-terminal voltammetry measuring method of direct current resistance.
Background technology
Measuring direct current resistance is the basic pilot project that a lot of power equipments need be carried out, such as water conservancy diversion contact of power transformer, reactor, discharge coil, transmission line of electricity, many power equipments or the like; The fundamental purpose of measuring direct current resistance is: the welding quality of checking the electrical equipment jointing, the equipment that has winding has or not winding interturn short-circuit, have the whether good and shunting switch physical location of equipment its each tap position contact of voltage tap switch and whether conform to indicating positions, stranded conductor and around connecting line whether situations such as the thigh of breaking are arranged.Therefore, the direct current resistance measurement requisite pilot project that is a lot of power equipments after handing-over, overhaul and the equipment that has a voltage tap switch change position of tapping switch also is the important inspection item after these device fails.
In working at the scene, realize the fast and accurate measurement of direct current resistance, not only help power system security, operation reliably, can also alleviate experiment work person's labour intensity.
The method introduction that tradition four terminal voltammetries are measured direct current resistance: as shown in Figure 1, when measuring direct current resistance, respectively add a current terminal contact and a voltage terminal usually at tested power equipment two ends, below tested power equipment abbreviate test product as; (C1 is C2) to the electric current of a stability number of test product input, simultaneously by two current terminal contacts, (P1 P2) carries out voltage sampling to test product, then by two voltage terminals, by resulting voltage and magnitude of current application Ohm law are directly calculated, can try to achieve direct current resistance R;
When four terminal voltammetries are measured direct current resistance, respectively be added with one " current terminal contact+voltage terminal " combination at the test product two ends, usually a such combination called a measuring sensor; When a measuring sensor was added on an end of test product, the self-resistance and the contact resistance of the measuring lead wire on the measuring sensor belonged to series relationship; Self-resistance and the contact resistance series connection back of supposing the measuring lead wire on a measuring sensor of test product head end are resistance R 1, and setting this measuring sensor head end is A; The self-resistance of the measuring lead wire on a measuring sensor of test product end and contact resistance series connection back are resistance R 2, set the terminal B of being of this measuring sensor; The direct current resistance of test product itself is Rs, is series relationship because of resistance R 1, resistance R 2, resistance R s three then, so the direct current resistance R=resistance R 1+ resistance R s+ resistance R 2 that four terminal voltammetries are measured, wherein, resistance R 1 and resistance R 2 are error resistance;
Be not difficult to find out that from above traditional four terminal voltammetries are measured direct current resistance needs a pair of measuring sensor, totally four terminals by one-shot measurement, calculate dc resistance then, and it has operation thinking advantage simply and intuitively;
But, adopt traditional four terminal voltammetries to measure in the direct current resistance process, will there be considerable influence in its inherent error to measurement data; For the influence of the error resistance of the measuring sensor of making great efforts to reduce the test product two ends to measurement result, at the scene in the actual measurement, vast testing crew a large amount of preliminary work of having to carry out in advance, such as removing whole wire clamps and fastening bolt, polishing measurement surface of contact, the contact area that increases measuring sensor and test product and contact pressure or the like the measure that is connected with test product, carry out repeated measurement then to reduce this error to greatest extent; During these measures are implemented at the scene, because tear, connect time and the human and material resources of fixture wire open through the wasteful amount of regular meeting, and, not careful if the staff works, also can stay potential safety hazard at the lead-in wire connecting portion of equipment, effect neither be very desirable; Especially run into the relatively more nervous repairing work of time requirement, in the time of need carrying out the direct current resistance measurement,, and then have influence on the correctness of higher level department maintenance decision also often because this measuring error makes surveying work make a fault too greatly;
In view of this, how can thoroughly eliminate of the influence of the contact resistance of the self-resistance of measuring lead wire of measuring sensor and measuring sensor and test product to the direct current resistance test result, improving the accuracy that direct current resistance is measured, is the problem that a lot of experiment work persons press for solution.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, provide a kind of and be skillfully constructed, operation steps is simple, it is convenient to measure, measurement data eight-terminal voltammetry measuring method of direct current resistance accurately.
The technical solution adopted in the present invention is as follows: a kind of eight-terminal voltammetry measuring method of direct current resistance, comprise the steps: to connect first current terminal contact, the 3rd current terminal contact, the first voltage terminal and tertiary voltage terminal, connect second current terminal contact, the 4th current terminal contact, the second voltage terminal and the 4th voltage terminal at the tested power equipment other end at tested power equipment one end;
First current terminal contact and the first voltage terminal constitute a measuring sensor, and the internal resistance of this measuring sensor is R1; Second current terminal contact and the second voltage terminal constitute a measuring sensor, and the internal resistance of this measuring sensor is R2; The 3rd current terminal contact and tertiary voltage terminal constitute a measuring sensor, and the internal resistance of this measuring sensor is R3; The 4th current terminal contact and the 4th voltage terminal constitute a measuring sensor, and the internal resistance of this measuring sensor is R4; The direct current resistance of tested power equipment is Rs;
By first current terminal contact and the 3rd current terminal contact tested power equipment input dc power is flowed I1, and by the first voltage terminal and tertiary voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 1, then, calculating can get direct current resistance Ru according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Ru=R1+R3;
By second current terminal contact and the 4th current terminal contact tested power equipment input dc power is flowed I2, and by the second voltage terminal and the 4th voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 2, then, calculating can get direct current resistance Rv according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Rv=R2+R4;
By first current terminal contact and second current terminal contact tested power equipment input dc power is flowed I3, and by the first voltage terminal and the second voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 3, then, calculating can get direct current resistance Rw according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Rw=R1+Rs+R2;
By first current terminal contact and the 4th current terminal contact tested power equipment input dc power is flowed I4, and by the first voltage terminal and the 4th voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 4, then, calculating can get direct current resistance Rx according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Rx=R1+Rs+R4;
By second current terminal contact and the 3rd current terminal contact tested power equipment input dc power is flowed I5, and by the second voltage terminal and tertiary voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 5, then, calculating can get direct current resistance Ry according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Ry=R2+Rs+R3;
By the 3rd current terminal contact and the 4th current terminal contact tested power equipment input dc power is flowed I6, and by tertiary voltage terminal and the 4th voltage terminal tested power equipment is carried out DC voltage and take a sample, get voltage U 6, then, calculating can get direct current resistance Rz according to Ohm law; Flow through the path as can be known by electric current, get arithmetic equation formula: Rz=R3+Rs+R4;
With above-mentioned six arithmetic equation formula simultaneous solutions, the direct current resistance that can get tested power equipment is Rs=(Rw+Rx+Ry+Rz-2 (Ru+Rv))/4.
The relative prior art of the present invention has outstanding substantive distinguishing features and obvious improvement, specifically, adopt this eight-terminal voltammetry measuring method of direct current resistance to measure direct current resistance and need two pairs of measuring sensors, totally eight terminals, by six measurements, calculate dc resistance then; Though this method has increased measuring sensor and has measured number of times, make measuring process seem complicated, but, because just there is not the composition of error resistance in its final result of calculation at all, so, in the actual measurement, do not need to carry out in advance more a large amount of preliminary work at the scene, saved a large amount of time and human and material resources, more can not stay potential safety hazard at the lead-in wire connecting portion of power equipment because of human factor; The measured data of this method can directly offer the decision maker because be accurate measurement result, and do not worry comprising error percentage in measured data and make the decision maker make false judgment; This method have be skillfully constructed, operation steps is simple, it is convenient to measure, measurement data advantage accurately.
Description of drawings
Fig. 1 adopts traditional four terminal voltammetries to measure the circuit diagram of direct current resistance;
Fig. 2 be adopt the present invention measure direct current resistance circuit diagram.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail.
To the research of in-site measurement work, on four terminal voltammetry based measurement, increase a pair of measuring sensor again through for a long time, promptly increase by four terminals again, use the voltammetry of eight terminals and carry out the direct current resistance surveying work.
As shown in Figure 2, a kind of eight-terminal voltammetry measuring method of direct current resistance, specific as follows:
Tested power equipment one end connect two current terminal contacts (C1, C3) and two voltage terminals (P1, P3), the tested power equipment other end connect two current terminal contacts (C2, C4) and two voltage terminals (P2, P4);
Current terminal contact C1 and voltage terminal P1 constitute a measuring sensor, and the internal resistance of this measuring sensor is R1, and its head end is A; Current terminal contact C2 and voltage terminal P2 constitute a measuring sensor, and the internal resistance of this measuring sensor is R2, and its end is B; Current terminal contact C3 and voltage terminal P3 constitute a measuring sensor, and the internal resistance of this measuring sensor is R3, and its head end is C; Current terminal contact C4 and voltage terminal P4 constitute a measuring sensor, and the internal resistance of this measuring sensor is R4, and its end is D; The direct current resistance of tested power equipment is Rs;
The internal resistance of described measuring sensor is meant the self-resistance of measuring lead wire of this measuring sensor and the contact resistance of this measuring sensor and tested power equipment, and wherein, described self-resistance and described contact resistance are series relationship;
The first step: make B, D two ends unsettled, apply DC current and measure at A, C two ends then, specifically: tested power equipment input dc power is flowed I1 by current terminal contact C1 and current terminal contact C3, and by voltage terminal P1 and voltage terminal P3 tested power equipment is carried out DC voltage and take a sample, get voltage U 1, then, calculating can get direct current resistance Ru according to Ohm law; Current path is: A-R1-R3-C, flow through the path as can be known by electric current, and get arithmetic equation formula: Ru=R1+R3;
Second step: make A, C two ends unsettled, apply DC current and measure at B, D two ends then, specifically: tested power equipment input dc power is flowed I2 by current terminal contact C2 and current terminal contact C4, and by voltage terminal P2 and voltage terminal P4 tested power equipment is carried out DC voltage and take a sample, get voltage U 2, then, calculating can get direct current resistance Rv according to Ohm law; Current path is: B-R2-R4-D, flow through the path as can be known by electric current, and get arithmetic equation formula: Rv=R2+R4;
The 3rd step: make C, D two ends unsettled, apply DC current and measure at A, B two ends then, specifically: tested power equipment input dc power is flowed I3 by current terminal contact C1 and current terminal contact C2, and by voltage terminal P1 and voltage terminal P2 tested power equipment is carried out DC voltage and take a sample, get voltage U 3, then, calculating can get direct current resistance Rw according to Ohm law; Current path is: A-R1-RS-R2-B, flow through the path as can be known by electric current, and get arithmetic equation formula: Rw=R1+Rs+R2;
The 4th step: make C, B two ends unsettled, apply DC current and measure at A, D two ends then, specifically: tested power equipment input dc power is flowed I4 by current terminal contact C1 and current terminal contact C4, and by voltage terminal P1 and voltage terminal P4 tested power equipment is carried out DC voltage and take a sample, get voltage U 4, then, calculating can get direct current resistance Rx according to Ohm law; Current path is: A-R1-RS-R4-D, flow through the path as can be known by electric current, and get arithmetic equation formula: Rx=R1+Rs+R4;
The 5th step: make A, D two ends unsettled, apply DC current and measure at C, B two ends then, specifically: tested power equipment input dc power is flowed I5 by current terminal contact C2 and current terminal contact C3, and by voltage terminal P2 and voltage terminal P3 tested power equipment is carried out DC voltage and take a sample, get voltage U 5, then, calculating can get direct current resistance Ry according to Ohm law; Current path is: C-R3-RS-R2-B, flow through the path as can be known by electric current, and get arithmetic equation formula: Ry=R2+Rs+R3;
The 6th step: make A, B two ends unsettled, apply DC current and measure at C, D two ends then, specifically: tested power equipment input dc power is flowed I6 by current terminal contact C3 and current terminal contact C4, and by voltage terminal P3 and voltage terminal P4 tested power equipment is carried out DC voltage and take a sample, get voltage U 6, then, calculating can get direct current resistance Rz according to Ohm law; Current path is: A-R3-RS-R4-D, flow through the path as can be known by electric current, and get arithmetic equation formula: Rz=R3+Rs+R4;
With above-mentioned six arithmetic equation formula simultaneous solutions, the direct current resistance that can get tested power equipment is Rs=(Rw+Rx+Ry+Rz-2 (Ru+Rv))/4.
Should be noted that at last: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit; Although with reference to preferred embodiment the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or the part technical characterictic is equal to replacement the specific embodiment of the present invention; And not breaking away from the spirit of technical solution of the present invention, it all should be encompassed in the middle of the technical scheme scope that the present invention asks for protection.