CN203707761U - 10kV distribution transformer neutral line breaking trip device - Google Patents

Abstract

The utility model discloses a 10kV distribution transformer neutral line breaking trip device which is composed of a neutral line breaking trip module, a residual current operated protective device, a fuse and an alternating-current contactor. The neutral line breaking trip module is connected into a low-voltage-side three-phase power source for monitoring. The neutral line breaking trip module is further connected with any phase of the low-voltage-side three-phase power source through the fuse. The neutral line breaking trip device is connected with the residual current operated protective device. The residual current operated protective device is connected with the alternating-current contactor. The neutral line breaking trip module, the residual current operated protective device and the alternating-current contactor are connected with a neutral line separately. The 10kV distribution transformer neutral line breaking trip device of the utility model has the following advantages that monitoring is performed on the low-voltage-side three-phase voltage by arranging the neutral line breaking trip module at the low-voltage side, and the residual current operated protective device and the alternating-current contactor are combined, so the line neutral line broken line overvoltage and undervoltage protection can be realized to prevent the burnout of user equipment.

Description

A 10kV distribution transformer neutral line disconnection tripping device

technical field

The utility model relates to the technical field of neutral wire protection of a three-phase four-wire power supply system, in particular to a neutral wire disconnection tripping device.

Background technique

In a three-phase four-wire power supply system, the neutral wire is the common return wire of the three-phase circuit. The neutral line can ensure that the three-phase loads become three independent circuits that do not affect each other; regardless of whether the loads of each phase are balanced, the loads of each phase can withstand symmetrical phase voltages, that is, no matter which phase fails, the other two phases can be normal Work. The neutral wire of the transformer is grounded with a steel strand fixed angle iron. When the steel strand is broken or the steel strand is in poor contact with the angle iron, the neutral wire of the transformer will be disconnected. Once a 10KV distribution transformer occurs If the neutral line is disconnected, the voltage on the low-voltage side will be distorted, which will increase or decrease the user voltage, and cause the user's electrical equipment to burn out.

The tripping device on the low-voltage side of the current three-phase four-wire power supply system can only detect the disconnection fault of the three-phase line, but cannot detect the disconnection fault of the neutral line in time, and cannot provide overvoltage and undervoltage protection, which may cause user equipment damage.

Utility model content

The technical problem solved by the utility model: In the three-phase four-wire power supply system, after the neutral line breaks down, the voltage on the low-voltage side will be distorted, which will further cause the user's electrical equipment to burn out.

In order to solve the above technical problems, a 10kV distribution transformer neutral line disconnection tripping device of the utility model is composed of a neutral line disconnection tripping module, a residual current action protector, a fuse and an AC contactor. The disconnection trip module has five input terminals and one output terminal, the residual current action protector has one input terminal and two output terminals, the AC contactor has one input terminal and one output terminal, and the neutral Four of the input terminals of the disconnection tripping module are respectively connected to the three-phase power supply on the low-voltage side and the neutral line, and the other input terminal is connected to any phase of the three-phase power supply on the low-voltage side after passing through the fuse, and its output terminal is connected to the input terminal of the residual current operated protector, one output terminal of the residual current operated protector is connected to the neutral line, and the other output terminal is connected to the input terminal of the AC contactor, and the AC contactor The output end of the AC contactor is connected to the neutral line, and the three contact points of the AC contactor are respectively connected to the low-voltage side three-phase power supply.

The working principle of the utility model is:

Connect the three-phase power supply and the neutral line on the low-voltage side to the neutral line disconnection tripping module. The three-phase load voltage of the phase power supply voltage is no longer symmetrical, so the voltage of each phase load changes, and the neutral line disconnection trip module monitors the voltage of each phase. When the protection threshold is reached, the input power to the residual current action protector will be cut off through the control of the neutral line disconnection trip module, so that the inductance coil of the AC contactor will be de-energized, and the three contact points will pop open to realize the low-voltage side three-phase The disconnection of the power line protects the user's electrical equipment from being burned out, thus realizing the protection of the neutral line disconnection.

The neutral line disconnection tripping module is composed of a power switch and a voltage monitoring module, the power switch is three single-control switches connected in parallel, and the voltage detection module has three ports respectively connected to the three single-control switches Connect to the low-voltage side three-phase power supply, the voltage detection module has one port connected to the neutral line, and the voltage detection module has two ports as the input terminals connected to the fuse and the residual current action protector connected output.

The voltage monitoring module is an existing technology, which can accurately detect three-phase voltage, and has overvoltage, undervoltage, and phase loss protection functions. Among them, the overvoltage and undervoltage thresholds and the output delay are adjustable. The three-phase power supply on the low-voltage side is connected to the voltage monitoring module through the power switch, so that the loop voltage is monitored by the voltage monitoring module.

The utility model has the beneficial effects of monitoring the three-phase voltage on the low-voltage side by setting a neutral wire disconnection trip module on the low-voltage side, and combining the residual current action protector and the AC contactor to realize the detection of neutral wire disconnection in the line. Line overvoltage and undervoltage protection to prevent user equipment from burning out. In addition, the 10kV distribution transformer neutral line disconnection tripping device of the utility model can also monitor the voltage of the low-voltage side line and improve the voltage qualification rate.

Description of drawings

Fig. 1 is a schematic diagram of a 10kV distribution transformer neutral wire disconnection tripping device of the present invention.

Fig. 2 is a schematic diagram of a neutral line breakage tripping module in a 10kV distribution transformer neutral line breakage tripping device of the present invention.

Detailed ways

Further description will be made below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 and Fig. 2 show a specific embodiment of a 10kV distribution transformer neutral line disconnection tripping device of the present invention. A 10kV distribution transformer neutral wire disconnection tripping device of the utility model is composed of a neutral wire disconnection tripping module 1, a residual current action protector 2, a fuse 3 and an AC contactor 4. Line tripping module 1 has five input terminals and one output terminal, said residual current operated protector 2 has one input terminal and two output terminals, said AC contactor 4 has one input terminal and one output terminal, and said middle Four of the input ends of the neutral line disconnection tripping module 1 are respectively connected to the three-phase power supply on the low-voltage side and the neutral line, and the other input end is connected to any phase of the three-phase power supply on the low-voltage side after passing through the fuse 3 , the output end of which is connected to the input end of the residual current operating protector 2, one output end of the residual current operating protector 2 is connected to the neutral line, and the other output end is connected to the input end of the AC contactor 4 The output end of the AC contactor 4 is connected to the neutral line, and the three contact points of the AC contactor 4 are respectively connected to the low-voltage side three-phase power supply. The neutral line disconnection tripping module 1 is composed of a power switch 1-1 and a voltage monitoring module 1-2, the power switch 1-1 is three single-control switches connected in parallel, and the voltage detection module 1- 2 There are three ports respectively connected to three single-control switches and then connected to the low-voltage side three-phase power supply, the voltage detection module 1-2 has one port connected to the neutral line, and the voltage detection module also has two ports as The input terminal connected to the fuse 3 is connected to the output terminal connected to the residual current operated protector 2 .

According to the regulation of the rated voltage of home appliances in my country is 220V, electrical appliances are allowed to operate at 1.1 times the rated voltage, the overvoltage threshold of the voltage detection module is set to 242V, and the undervoltage threshold is set to 198V. At the same time, in order to prevent malfunction, set the delay time 3~8s. The three-phase power supply on the low-voltage side is connected to the neutral line disconnection trip module. When the neutral line is disconnected, in the circuit with unbalanced three-phase load, the neutral point of the load will be displaced, and the three-phase load voltage will no longer be symmetrical. , so the voltage of each phase load changes, and the neutral wire breakage trip module monitors the voltage of each phase. When the overvoltage and undervoltage protection thresholds preset by the neutral wire breakage trip module are exceeded, The control of the trip module cuts off the power supply of the residual current action protector, so that the inductance coil of the AC contactor is de-energized, the contact point is disconnected, the circuit is disconnected, and the user's electrical equipment is not burned out, thus realizing the Protection against neutral wire break. The voltage monitoring module realizes the voltage monitoring function in the neutral line disconnection tripping module.

The parts not involved in the utility model are all the same as the prior art or implemented by adopting the prior art.

Claims (2)

1. A 10kV distribution transformer neutral line disconnection tripping device, characterized in that it consists of a neutral line disconnection tripping module (1), a residual current action protector (2), a fuse (3) and an AC contactor ( 4) composition, the neutral line disconnection tripping module (1) has five input terminals and one output terminal, the residual current action protector (2) has one input terminal and two output terminals, and the AC contact The device (4) has an input terminal and an output terminal, and the four input terminals of the neutral line disconnection tripping module (1) are respectively connected to the low-voltage side three-phase power supply and the neutral line, and the other input terminal is passed through The fuse (3) is connected to any phase of the three-phase power supply on the low-voltage side, and its output terminal is connected to the input terminal of the residual current operated protector (2), and the residual current operated protector (2) One output end of the AC contactor (4) is connected to the neutral line, the other output end is connected to the input end of the AC contactor (4), the output end of the AC contactor (4) is connected to the neutral line, and the AC contactor (4) The three contact points are respectively connected to the three-phase power supply on the low-voltage side. 2. The 10kV distribution transformer neutral wire disconnection tripping device according to claim 1, characterized in that: the neutral wire disconnection tripping module (1) consists of a power switch (1-1) and a voltage monitoring module (1-2), the power switch (1-1) is three single-control switches connected in parallel, and the voltage detection module (1-2) has three ports respectively connected to the three single-control switches to connect to the low voltage side three-phase power supply, the voltage detection module (1-2) has one port connected to the neutral line, the voltage detection module also has two ports as the input connected to the fuse (3) and the The output terminal connected to the residual current operated protector (2).