CN2515854Y

CN2515854Y - Overvoltage protector

Info

Publication number: CN2515854Y
Application number: CN 01229764
Authority: CN
Inventors: 肖如泉
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2001-07-06
Filing date: 2001-07-06
Publication date: 2002-10-09
Anticipated expiration: 2011-07-06

Abstract

The utility model belongs to the technical field of low-voltage electrical equipment, and comprises several non-linear resistance elements R _Z , and several parallel capacitances C and several series inductances L. The utility model has the advantages of fast action time and stable operation, and can be widely used for overvoltage protection of low-voltage electrical equipment.

Description

Overvoltage protection device

Technical field

The utility model belongs to the low voltage electrical equipment technical field, and is particularly a kind of as the protective device that suppresses and absorb temporary overvoltage.

Background technology

Overvoltage protection device ensures that to the infringement of low voltage electrical equipment (as: low-voltage equipment in computer, low-voltage electrical apparatus, telephone exchange, the electrion etc.) elimination lightning overvoltage, internal overvoltage the low voltage electrical equipment safe operation plays a very good protection.

In the protector that can see on the market, be to utilize nonlinear resistive element to suppress superpotential mostly now, this element function instability is about the microsecond level operate time that has, and can reach nanosecond the operate time that has.Because operate time, instability may also very high overvoltage can occur on nonlinear resistance, can not well protect electric equipment.Its wiring is shown in Fig. 1 (a), and nonlinear resistive element also is connected on the protected circuit, and the voltage-current characteristic of this element is shown in Fig. 1 (b), and under normal working voltage (as 220V), its voltage is U ₁, by the electric current I of element ₁, when the overvoltage that surpasses operating voltage arrived circuit, the electric current by element was I ₂,,, therefore can play inhibitory action to overvoltage so very high voltage can not occur at the two ends of nonlinear resistive element because the U-I curve of this element is a saturation curve.

Summary of the invention

The purpose of this utility model is for overcoming the weak point of prior art, propose a kind of overvoltage protection device, and it is fast to have an operate time, and the advantage of working stability, can be widely used in the overvoltage protection to low voltage electrical equipment.

The utility model has designed a kind of overvoltage protection device, comprises a plurality of nonlinear resistive element R _Z, it is characterized in that, be connected with the first nonlinear resistive element R at power end _Z, this first nonlinear resistive element R _ZTwo ends connect the first capacitor C group of forming by the capacitor C of two series connection, the mid point of two capacitor C of this first capacitor C group links to each other with ground wire, at second, third nonlinear resistance of the two ends of this each capacitor C parallel connection R _Z, the said first nonlinear resistive element R _ZThe two ends a pair of inductance L of also connecting respectively, the mid point of these two pairs of inductance L connects the second capacitor C group of being made up of the capacitor C of two series connection, the mid point of this second capacitor C group is connected on the earth connection.

The said inductance L of the utility model can be tens μ H to tens mH, and said capacitor C can be hundreds of PF to hundreds of μ F, said nonlinear resistance R _Z, can be 1A to 10kA.

The utility model also can comprise the protective tube R that is connected in power end _DWith indicator light D.

Principle of the present utility model:

Because the impedance of electric capacity is very big under low frequency, the impedance of inductance is very little, so power current can be smoothly by arriving load.Under high frequency situations (when overvoltage is arranged), the impedance of electric capacity is very little, and the impedance of inductance is very big; so overvoltage can be suppressed in this protector well; served as time of voltage wave when very little (as nanosecond), the better effects if of filtering then, thereby can better protect equipment.

Characteristics of the present utility model and application:

The utility model can filter out the overvoltage ripple.From the overvoltage ripple is carried out theory analysis as can be known, so-called overvoltage comprises: 1, lightning overvoltage, 2, internal overvoltage.These superpotential paces of change are very fast, are a kind of single pulse voltage waves as the thunder and lightning overvoltage, the about 1-2 microsecond of transformation period, and being equivalent to frequency is the hundreds of KHz.The circuit of the utility model design can pass through operating frequency for 50 hertz to arrive protected device smoothly, and the overvoltage ripple is then suppressed by circuit of the present utility model.

Overvoltage protection device of the present utility model can be widely used on the low voltage electrical equipment; only lift a few example explanations below; 1, overvoltage protection device is used for the low-voltage equipment of high-pressure discharging device, as the protection of control cubicle low-tension supply, the protection of measuring instrument, the protection of electric rotating machine.

2, computer, oscillographic protection.When the thunder discharge phenomenon takes place, through the break situation of oscilloscope, computer of regular meeting.After adding overvoltage protection device, can well protect oscilloscope, computer.

Description of drawings

The overvoltage protection schematic diagram of the existing employing nonlinear resistance of Fig. 1,

Wherein (a) is the circuit connection diagram, (b) is the circuit characteristic schematic diagram.

Fig. 2 is the utility model circuit connection diagram,

Embodiment

A kind of overvoltage protection device embodiment of the utility model design as shown in Figure 2, by 4 shunt capacitance C, 4 series inductance L, 3 nonlinear resistive element R _Z, two protective tube RD and indicator light D that are connected in power end constitute, shown in Fig. 2 (a), the parameter of its each element is: shunt capacitance C is that 1-2 μ F, series inductance L are 0.1-0.2mH, nonlinear resistive element R _ZBe 10-20kA.

The frequency protection characteristic of present embodiment is shown in Fig. 2 (b), and when frequency is high more, overvoltage is easy more to be absorbed.

Claims

1, a kind of overvoltage protection device comprises a plurality of nonlinear resistive element R _Z, it is characterized in that, be connected with the first nonlinear resistive element R at power end _Z, this first nonlinear resistive element R _ZTwo ends connect the first capacitor C group of forming by the capacitor C of two series connection, the mid point of two capacitor C of this first capacitor C group links to each other with ground wire, at second, third nonlinear resistance of the two ends of this each capacitor C parallel connection R _Z, the said first nonlinear resistive element R _ZThe two ends a pair of inductance L of also connecting respectively, the mid point of these two pairs of inductance L connects the second capacitor C group of being made up of the capacitor C of two series connection, the mid point of this second capacitor C group is connected on the earth connection.

2, overvoltage protection device as claimed in claim 1 is characterized in that, said inductance L is tens μ H to tens mH, said capacitor C be hundreds of PF to hundreds of μ F, said nonlinear resistance R _ZFor 1A to 10kA.

3, overvoltage protection device as claimed in claim 1 is characterized in that, also comprises the protective tube RD and the indicator light D that are connected in power end.