CN104267297A - Testing circuit, device and method for capacitor discharge speed - Google Patents

Abstract

The present application discloses a capacitor discharge speed testing circuit, testing device and testing method. The testing circuit includes: a power supply circuit for supplying power to the capacitor, connected in parallel with the capacitor, and a voltage divider for detecting the voltage of the capacitor. The capacitor The first common end of the voltage divider is connected to the first end of the discharge switch, and the capacitor and the second common end of the voltage divider pass through a shunt, an additional resistor, a discharge device, and the discharge switch in sequence. The second end is connected. The test circuit provided by this application can supply power to the capacitor through the power circuit, simulate the residual DC voltage after the capacitor is switched off, then disconnect the power circuit, close the discharge switch, use the accessory circuit and the discharge device to discharge the capacitor, and pass A voltage divider and a shunt are used to detect the discharge voltage and discharge current to achieve the purpose of detecting the influence of different discharge devices on the discharge speed of the capacitor.

Description

A capacitor discharge speed test circuit, test device and test method

technical field

The present application relates to the technical field of capacitor detection, and more specifically, to a capacitor discharge speed testing circuit, testing device and testing method.

Background technique

As a capacitive component, the shunt capacitor bank is widely used in the reactive power compensation of the power grid to improve the voltage and power factor of the power grid and reduce the damage of the line.

When the switch breaks the parallel capacitor bank, due to the particularity of the load, there is a higher recovery voltage between the contacts. After breaking the current and extinguishing the arc, the residual charge on the capacitor bank cannot be released in a short time, and the power supply voltage and the residual voltage on the capacitor bank are reversed, causing the breaker to withstand a high recovery overvoltage for a long time. The dielectric recovery strength of the device cannot withstand the recovery overvoltage applied to it, and arc reignition is very easy to occur.

In order to solve this problem, a discharge device is generally used to discharge the parallel capacitor. However, the prior art lacks a solution for testing the influence of different discharge devices on the discharge speed of the capacitor, and it is impossible to determine whether the discharge device meets the requirements for the discharge speed of the residual voltage of the capacitor.

Contents of the invention

In view of this, the present application provides a capacitor discharge speed test circuit, a test device and a test method, which are used to provide a capacitor discharge speed test scheme to verify the influence of different types of discharge devices on the discharge speed of the residual voltage of the capacitor.

In order to achieve the above purpose, the proposed scheme is as follows:

A capacitor discharge speed test circuit, comprising:

a power circuit for powering the capacitor, the power circuit including a power switch;

a voltage divider connected in parallel with the capacitor to sense the capacitor voltage;

The capacitor and the first common end of the voltage divider are connected to the first end of the discharge switch, and the capacitor and the second common end of the voltage divider are connected to the first end of the voltage divider through a shunt, an additional resistor, and a discharge device in sequence. The second terminals of the discharge switch are connected to each other.

Preferably, when the power supply circuit includes a voltage regulating transformer and a step-up transformer connected thereto,

The test circuit also includes a rectifier diode, and the rectifier diode is arranged on the secondary side of the step-up transformer.

Preferably, the power supply circuit is a switching power supply or a linear power supply.

Preferably, it also includes:

Zener diode in parallel with the capacitor.

Preferably, it also includes:

A thermistor connected in series with the secondary side of the step-up transformer.

Preferably, the voltage divider is a DC voltage divider.

Preferably, the shunt is a DC shunt.

Preferably, the additional resistor is a sliding rheostat.

A capacitor discharge speed testing device, comprising the above-mentioned capacitor discharge speed test circuit, and a casing arranged outside the capacitor discharge speed test circuit.

A capacitor discharge speed test method, applied to the above-mentioned capacitor discharge speed test circuit, the method includes:

using the power supply circuit to charge the capacitor;

Determine whether the voltage value displayed by the voltage divider reaches the preset value;

If so, then disconnect the power supply circuit and close the discharge switch;

Using the voltage and current values output by the voltage divider and the shunt, the capacitor discharge rate is determined.

It can be seen from the above technical solutions that the capacitor discharge speed test circuit provided by the embodiment of the present application includes: a power supply circuit for supplying power to the capacitor, connected in parallel with the capacitor, and a voltage divider for detecting the voltage of the capacitor, the The capacitor is connected to the first common end of the voltage divider and the first end of the discharge switch, and the capacitor and the second common end of the voltage divider pass through a shunt, an additional resistor, a discharge device, and the discharge switch in sequence. connected to the second end. The test circuit provided by this application can supply power to the capacitor through the power circuit, simulate the residual DC voltage after the capacitor is switched off, then disconnect the power circuit, close the discharge switch, use the accessory circuit and the discharge device to discharge the capacitor, and pass A voltage divider and a shunt are used to detect the discharge voltage and discharge current to achieve the purpose of detecting the influence of different discharge devices on the discharge speed of the capacitor.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present application, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

FIG. 1 is a schematic structural diagram of a capacitor discharge speed test circuit disclosed in an embodiment of the present application;

2 is a schematic structural diagram of another capacitor discharge speed test circuit disclosed in the embodiment of the present application;

Fig. 3 is a flow chart of a method for testing the discharge speed of a capacitor disclosed in the embodiment of the present application;

FIG. 4 is a schematic structural diagram of another capacitor discharge speed testing circuit disclosed in the embodiment of the present application.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram of a capacitor discharge speed test circuit disclosed in an embodiment of the present application.

As shown in Figure 1, the circuit consists of:

A power supply circuit VCC for supplying power to the capacitor C;

Wherein, the power circuit VCC can supply power to the capacitor C to simulate the residual DC voltage after the capacitor is switched off. The power circuit VCC includes a power switch (not shown in FIG. 1 ), through which the switch of the power circuit can be controlled.

A voltage divider U connected in parallel with the capacitor C to detect the voltage of the capacitor C;

Among them, the voltage divider U can detect the voltage of the capacitor.

The capacitor C and the first common end of the voltage divider U are connected to the first end of the discharge switch K2, and the capacitor C and the second common end of the voltage divider U pass through the shunt A and the additional resistor in turn. R, the discharge device W is connected to the second terminal of the discharge switch K2.

Wherein, the discharge device W is a discharge device to be tested, and the discharge device W can discharge the capacitor C after the discharge switch K2 is combined. The accessory resistor R can simulate and adjust the discharge circuit resistance.

The capacitor discharge speed test circuit provided in the embodiment of the present application includes: a power supply circuit for supplying power to the capacitor, connected in parallel with the capacitor, and a voltage divider used to detect the voltage of the capacitor, and the capacitor and the first voltage divider of the voltage divider A common end is connected to the first end of the discharge switch, and the second common end of the capacitor and the voltage divider is connected to the second end of the discharge switch through a shunt, an additional resistor, and a discharge device in sequence. The test circuit provided by this application can supply power to the capacitor through the power circuit, simulate the residual DC voltage after the capacitor is switched off, then disconnect the power circuit, close the discharge switch, use the accessory circuit and the discharge device to discharge the capacitor, and pass A voltage divider and a shunt are used to detect the discharge voltage and discharge current to achieve the purpose of detecting the influence of different discharge devices on the discharge speed of the capacitor.

Referring to FIG. 2 , FIG. 2 is a schematic structural diagram of another capacitor discharge speed test circuit disclosed in an embodiment of the present application.

In FIG. 2 , the power supply circuit VCC is limited, which may include a voltage regulating transformer T1 and a step-up transformer T2. On this basis, a rectifier diode D needs to be added on the secondary side of the step-up transformer T2.

Wherein, the voltage regulating transformer T1 includes a power switch K1.

When using the test circuit shown in Figure 2 for testing, the specific implementation process is as follows: the whole process is divided into a charging process and a discharging process. The charging process is: close the power switch K1, open the discharge switch K2, adjust the voltage regulating transformer T1, boost the voltage through the step-up transformer T2, rectify through the rectifier diode D, charge the capacitor C, and monitor whether the DC voltage on the capacitor C reaches the preset value value, if not, continue to adjust the voltage regulating transformer T1 until the DC voltage on the capacitor C reaches the preset value. The discharge process is as follows: after the DC voltage on the capacitor C reaches the preset value, the power switch K1 is turned on, the discharge switch K2 is closed, and the DC voltage on the capacitor C is released through the discharge device W and the additional resistor R, and the voltage divider U and the shunt are used at the same time. A monitors the DC voltage and discharge circuit current of capacitor C to judge the discharge speed of the capacitor. The specific workflow is shown in Figure 3. The methods shown in Figure 3 include:

Step S100, using the power supply circuit to charge the capacitor;

Step S110, judging whether the voltage value displayed by the voltage divider reaches a preset value;

If yes, execute step S120, disconnect the power supply circuit, and close the discharge switch;

Step S130, using the voltage value and current value output by the voltage divider and the shunt to determine the discharge speed of the capacitor.

It should be noted that, in addition to being implemented in the manner shown in FIG. 2 , the power supply circuit can also be a switching power supply or a linear power supply, which can directly output DC current to charge the capacitor.

Further, referring to FIG. 4 , FIG. 4 is a schematic structural diagram of another capacitor discharge speed testing circuit disclosed in an embodiment of the present application.

Compared with FIG. 2 , a Zener diode DZ connected in parallel with the capacitor C is further added in FIG. 4 . The Zener diode prevents breakdown of the capacitor due to excessive voltage.

Furthermore, a thermistor can also be connected in series with the secondary side of the step-up transformer T2 to prevent surge impact.

It should be explained that the above voltage divider may be a DC voltage divider, and the shunt is a DC shunt. The accessory resistor can slide the rheostat for easy resistance adjustment.

On the basis of the above, the embodiment of the present application also provides a capacitor discharge speed test device, the test device includes a housing and a test circuit arranged in the housing, the test circuit is the capacitor discharge speed test circuit introduced above.

Finally, it should also be noted that in this text, relational terms such as first and second etc. are only used to distinguish one entity or operation from another, and do not necessarily require or imply that these entities or operations, any such actual relationship or order exists. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A capacitor discharge speed test circuit, characterized in that, comprising: a power circuit for powering the capacitor, the power circuit including a power switch; a voltage divider connected in parallel with the capacitor to sense the capacitor voltage; The capacitor and the first common end of the voltage divider are connected to the first end of the discharge switch, and the capacitor and the second common end of the voltage divider are connected to the first end of the voltage divider through a shunt, an additional resistor, and a discharge device in sequence. The second terminals of the discharge switch are connected to each other. 2. The test circuit according to claim 1, characterized in that, when the power supply circuit comprises a voltage regulating transformer and a step-up transformer connected thereto, The test circuit also includes a rectifier diode, and the rectifier diode is arranged on the secondary side of the step-up transformer. 3. The test circuit according to claim 1, wherein the power supply circuit is a switching power supply or a linear power supply. 4. The test circuit according to claim 2, further comprising: Zener diode in parallel with the capacitor. 5. The test circuit according to claim 2, further comprising: A thermistor connected in series with the secondary side of the step-up transformer. 6. The test circuit according to claim 2, wherein the voltage divider is a DC voltage divider. 7. The test circuit according to claim 2, wherein the shunt is a DC shunt. 8. The test circuit according to claim 2, wherein the additional resistor is a sliding rheostat. 9. A capacitor discharge speed test device, characterized in that it comprises the capacitor discharge speed test circuit according to any one of claims 1-8, and a casing arranged outside the capacitor discharge speed test circuit. 10. A capacitor discharge speed test method, characterized in that, it is applied in the capacitor discharge speed test circuit according to any one of claims 1-8, and the method comprises: using the power supply circuit to charge the capacitor; Determine whether the voltage value displayed by the voltage divider reaches the preset value; If so, then disconnect the power supply circuit and close the discharge switch; Using the voltage and current values output by the voltage divider and the shunt, the capacitor discharge rate is determined.