# US 12,009,164 B2 · Pulse voltage conditioning method of vacuum interrupter with automatic conditioning energy adjustment

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- Number: US 12,009,164 B2
- Document ID: US12009164B2
- Status: Granted
- Kind: B2
- Application number: 17/880,299
- Filed: 2022-08-03
- Published: 2022-11-24
- Granted: 2024-06-11
- Earliest claimed: 2021-08-24
- Assignees: Xi'an Jiaotong University
- Applicants: Xi'an Jiaotong University
- Inventors: Hui Ma; Jingyu Shen; Yingsan Geng; Zhiyuan Liu; Jianhua Wang; Jing Yan; Yu Du
- Web page: https://patentgrep.com/patent/US12009164B2

## CPC

- H01H 33/59: Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the AC cycle
- G01R 31/3272: {Apparatus, systems or circuits therefor (G01R31/3275 takes precedence)}
- H01H 33/664: Contacts; Arc-extinguishing means, e.g. arcing rings
- H03K 5/24: the characteristic being amplitude
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A pulse voltage conditioning method of a vacuum interrupter with automatic conditioning energy adjustment based on a trend of a breakdown voltage of the vacuum interrupter during a conditioning process. A current-limiting resistor and a parallel capacitor are automatically adjusted to ensure the conditioning energy reaching a critical value without deconditioning effect. The critical value refers to a maximum conditioning energy without damaging the electrode surfaces, namely an optimal conditioning energy, which can better remove insulation defects on the electrode surface and improve insulation performance of a vacuum gap. The problems of insufficient conditioning and deconditioning effect during conventional voltage conditioning process of the vacuum interrupter can be solved. Therefore, insulation strength of the vacuum interrupter can be raised to a higher level through conditioning.

## Claims

### Claim 1

A pulse voltage conditioning method of a vacuum interrupter with automatic conditioning energy adjustment, comprising steps of: decreasing a voltage if breakdown occurs and increasing the voltage if the breakdown does not occur, so as to adjust a conditioning energy based on a trend of a breakdown voltage of the vacuum interrupter during a conditioning process; automatically adjusting a current-limiting resistor and a parallel capacitor to optimize the conditioning energy, thereby removing insulation defects on electrode surfaces and improving insulation performance of a vacuum gap;
wherein the pulse voltage conditioning method comprises specific steps of:
step 1: according to a voltage level of the vacuum interrupter, determining a peak value of a conditioning initial pulse voltage Uc(0), which is P1 times of a breakdown voltage UL under a standard lightning impulse voltage of the vacuum interrupter at the voltage level, wherein P1 ranges from 20%-50%;
Uc(0)=P1·UL (1)
step 2: according to the conditioning initial pulse voltage, adjusting an initial conditioning energy to Qc(0), wherein Qc(0) ranges from 1-10 J; if an output energy of a pulse voltage source is larger than Qc(0), then connecting the current-limiting resistor in series to an output end of the pulse voltage source to decrease the conditioning energy; if the output energy is less than Qc(0), connecting the parallel capacitor to both ends of the vacuum interrupter to increase the conditioning energy;
step 3: successively applying a pulse voltage to the vacuum interrupter, measuring a breakdown voltage of the vacuum interrupter with a voltage divider, and measuring a breakdown current Ib(n) flowing through the vacuum interrupter with a current transformer; wherein if a peak value of a current flowing through the vacuum interrupter exceeds a critical value of a breakdown current Ibc, the vacuum interrupter is judged to break down, otherwise the vacuum interrupter withstands the pulse voltage; Ibc ranges from 10-20 mA;
Ib(n)≥Ibc (2)
if the vacuum interrupter breaks down, decreasing an applied pulse voltage in a next conditioning process by ΔU:
Uc(n+1)=Uc(n)−ΔU (3)
wherein a voltage step ΔU is P2 times of the breakdown voltage UL under the standard lightning impulse voltage of the vacuum interrupter at the voltage level, and P2 ranges from 1%-4%;
ΔU=P2·UL (4)
if the vacuum interrupter withstands the pulse voltage, increasing the applied pulse voltage in the next conditioning process by ΔU:
Uc(n+1)=Uc(n)+ΔU (5)
step 4: counting a trend of the breakdown voltage and a maximum breakdown voltage Ubmax during the conditioning process, and calculating the conditioning energy Qc(n) according to waveforms of a measured breakdown voltage Ub(n) and the breakdown current Ib(n):
Qc(n)=∫(Ub(n)·Ib(n)dt (6)
wherein if the breakdown voltage decreases to P3 times of the maximum breakdown voltage Ubmax, a deconditioning effect is judged to occur, and P3 ranges from 70%-90%;
Uc≤P3·Ucmax (7)
then increasing the current-limiting resistor or decreasing the parallel capacitor to decrease a next conditioning energy Qc(n+1) to P4 times of Qc(n), wherein P4 ranges from 80%-90%; meanwhile, counting the trend of breakdown voltage and the maximum breakdown voltage Ubmax again;
Qc(n+1)P4#Qc(n) (8)
step 5: if the deconditioning effect never occurs since beginning of the conditioning process, defining the conditioning energy as being low, and decreasing the current-limiting resistor or increasing the parallel capacitor to increase the next conditioning energy Qc(n+1) to P5 times of Qc(n), wherein P5 ranges from 105%-120%; if the deconditioning effect occurs, stopping increasing the conditioning energy, so as to gradually adjust the conditioning energy to a critical value where the deconditioning effect does not occur; wherein the critical value is a maximum conditioning energy without damaging the electrode surfaces, which is an optimal conditioning energy;
Qc(n+1)P5·Qc(n) (9) and
step 6: if the maximum breakdown voltage Ubmax of the vacuum interrupter does not increase in continuous Ns conditioning experiments during which the deconditioning effect does not occur, regarding insulation performance of the vacuum interrupter as optimal and ending the conditioning process, wherein Ns ranges from 300-500.

### Claim 2 (depends on 1)

The pulse voltage conditioning method, as recited in claim 1, wherein the automatic conditioning energy adjustment is realized by programming; the measured breakdown voltage and the breakdown current are input, and a control signal for adjusting the current-limiting resistor and the parallel capacitor is output.

### Claim 3 (depends on 1)

The pulse voltage conditioning method, as recited in claim 1, wherein a waveform of the applied pulse voltage is a standard lightning impulse voltage.

### Claim 4 (depends on 1)

The pulse voltage conditioning method, as recited in claim 1, wherein the current-limiting resistor is a slide rheostat, which smoothly adjusts a resistance value by controlling a position of a slip sheet; or the current-limiting resistor is a multi-level resistance module, which changes the resistance value by controlling switches of different resistances.

### Claim 5 (depends on 1)

The pulse voltage conditioning method, as recited in claim 1, wherein the parallel capacitor is a multi-level capacitance module, which changes a capacitance value by controlling switches of different capacitances.