CN201229390Y - AC cable voltage test device - Google Patents

Abstract

The utility model relates to a testing device of alternating current cable withstanding voltage, which is composed of a variable-frequency power source (1), a booster transformer (2), a series reactance (3) and a voltage-dividing capacitor (4) which are connected in series in turn in a two-phase mode, wherein the variable-frequency power source (1) is connected with the booster transformer (2) through a positive electrode of the variable-frequency power source, and a negative electrode is connected with the voltage-dividing capacitor (4). Resonant vibration is generated through adjusting the variable-frequency power source (1). When the variable-frequency power source outputs voltage of multiple hectovolts, voltages on two ends of a tested cable 5 can reach 10k V. The voltage which is actually output is measured through the voltage-dividing capacitor. The testing device has small volume and light weight, the labor intensity is alleviated, a resonance point can be searched automatically, pressure is added automatically, the device stops outputting automatically after finishing tests and has overvoltage protection, over current protection, breakdown protection and the like, and even if the tested cable is broken down, electric arc on the position of breakdown can not enlarge trouble spots, which is convenient for checking and repairing.

Description

Alternating current cable voltage test unit

Technical field

The utility model belongs to electric power equipment technical field, relates in particular to a kind of alternating current cable voltage test unit.

Background technology

For ensureing that operation power is normal, cable is coming into operation before and just in use all must be by withstand voltage test and detection.Traditional cable voltage test often adopts the direct-current experiment experiment device to carry out.But when using the direct-current experiment experiment device to carry out withstand voltage test and detect, the insulated electro field distribution is different with Electric Field Distribution under the alternating current voltage, can not reflect the practical operation situation of cable machinery in AC network truly, and cause cable fault easily.Therefore, International Power association recommend to adopt the alternating current test method to carry out withstand voltage test and detection, and with this as commissioning test and the indispensable project of preventive trial.Not long ago occurred a kind of cable voltage test unit of transferring sensing mode on the market, but such installs not only volume heaviness, construction labour intensity is also bigger than normal.

The utility model content

The technical problems to be solved in the utility model is: at the defective of above-mentioned known technology, provide a kind of and can make things convenient for, carry out leggiero withstand voltage test, can not cause the alternating current cable voltage test unit of any damage again to cable.

Technical solution of the present utility model is, referring to Fig. 1, described alternating current cable voltage test unit as shown in Figure 1, by variable-frequency power sources 1, step-up transformer 2, series reactance 3 and dividing potential drop electric capacity 4 in regular turn two-phase be composed in series, wherein said variable-frequency power sources 1 anodal is electrically connected with described step-up transformer 2 by it, is electrically connected with described dividing potential drop electric capacity 4 by the negative pole of described variable-frequency power sources 1.When the alternating current cable voltage test unit of the present utility model that constitutes thus uses, the end that an end that only needs tested cable 5 that will be as shown in Figure 1 and the series reactance 3 of above-mentioned this device are connected with dividing potential drop electric capacity 4 that is the output terminal electrical connection of series reactance 3, the other end and above-mentioned variable-frequency power sources 1 same ground connection can be implemented withstand voltage test and detection to this tested cable 5.Principle of work of the present utility model is: by regulating the output frequency f of variable-frequency power sources 1, satisfy formula $f=\frac{1}{2\×\mathrm{\π}\×\sqrt{L\×C}},$ Circuit generation resonance.In the formula, L is the inductance size of series reactance 3, and C is the capacitance value of tested cable 5.During resonance, the voltage on the tested cable 5 is tens times of output voltage of variable-frequency power sources 1.Like this, when variable-frequency power sources was exported the voltage of several hectovolts, the voltage at tested cable 5 two ends can reach 10kV.Above-mentioned dividing potential drop electric capacity 4 is a capacitive divider, by this voltage divider, can measure the voltage swing of actual output.

The beneficial effects of the utility model are:

1), device volume is little, in light weight, the requirement of suitable fully cable voltage test can alleviate the construction labour intensity of testing crew;

2), withstand voltage test automaticity height, have automatic searching tuning-points, automatically pressurization, off-test stop functions such as output automatically;

3), function is complete.Overvoltage protection, overcurrent protection, discharge prevention etc., complete;

4) even tested cable is breakdown, condition of resonance $f=\frac{1}{2\×\mathrm{\π}\×\sqrt{L\×C}}$ Relation is broken, and high-tension circuit and low-tension supply loop not only danger can not occur, and its electric current can reduce on the contrary, so thereby the electric arc of insulation course puncture place can not enlarge easy access with the trouble spot.

Description of drawings

Fig. 1 is the circuit diagram of a specific embodiment of the utility model alternating current cable voltage test unit, is denoted as among the figure:

1-variable-frequency power sources,

2-step-up transformer,

3-series reactance,

4-dividing potential drop electric capacity,

5-tested cable.

Embodiment

Referring to Fig. 1, the variable-frequency power sources 1 of the alternating current cable voltage test unit of present embodiment adopts Hunan China to economize the BPNY-10A type variable-frequency power sources that the pure Power Tech Corp. Inc. of remittance produces.The input voltage of this power supply is 220V, and frequency is 50Hz, and magnitude of current maximal value is 23A, and output voltage is that 0～250V is adjustable, and output frequency is that 30～300Hz is adjustable, and the frequency adjustment precision is 0.1Hz; Its step-up transformer 2 adopt Chinese Hubei to continue power that new extraordinary electric incorporated company produces is the CXB type step-up transformer of 6kVA, this step-up transformer maximum output voltage is 750V; Series reactance 3 then adopts Chinese Shanghai ripple sky electrical equipment Manufacturing Co., Ltd to produce CKSG-10 type current-limiting reactor, and this reactor operating voltage is 12.8kV, and maximum operating currenbt is 8A, and rated power is 100kVA.The reactor that it is 100kVA that this series reactance 3 also can adopt commercially available any a power; The dividing potential drop electric capacity 4 of present embodiment adopts Chinese Foochow to produce FC-60 type dividing potential drop electric capacity along bright Electrical Appliances Co., Ltd.The rated voltage of this dividing potential drop electric capacity is that 60kV, electric capacity are 250pF.Above-mentioned variable-frequency power sources 1, step-up transformer 2, series reactance 3 and dividing potential drop electric capacity 4 are by above-mentioned technical solution, and reference circuit diagram shown in Figure 1 is connected in regular turn and can be constituted alternating current cable voltage test unit of the present utility model.

The alternating current cable voltage test unit of the present utility model of Gou Chenging is proved to be respond well through manufacturing experimently to try out thus, but testing length is the cable of 15m～5000m, and easy to use, safe and reliable, reaches designing requirement fully.

Claims (1)

1, a kind of alternating current cable voltage test unit, it is characterized in that, it by variable-frequency power sources (1), step-up transformer (2), series reactance (3) and dividing potential drop electric capacity (4) in regular turn two-phase be composed in series, wherein said variable-frequency power sources (1) anodal is electrically connected with described step-up transformer (2) by it, is electrically connected with described dividing potential drop electric capacity (4) by the negative pole of described variable-frequency power sources (1).

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