CN2200248Y

CN2200248Y - Automatic protector of low voltage electrifield wire netting controlled by computer

Info

Publication number: CN2200248Y
Application number: CN 94242349
Authority: CN
Inventors: 孙立平
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-08-03
Filing date: 1994-08-03
Publication date: 1995-06-07
Anticipated expiration: 2004-08-03

Abstract

The utility model relates to an automatic protector of a low voltage electric wire netting controlled by a computer, comprising a current and voltage sampling circuit, an electric leakage inductor and a computer control system. The utility model has the advantages that the automatic protector of the low voltage electric wire netting controlled by the computer can realize the automatic monitoring, the automatic judgement and the automatic error detection for transmission lines and simultaneously protect failures comprising overload, short circuits, broken circuits, electric leakage, etc. The utility model has high selectivity and sensitivity and can effectively judge instantaneous failures and permanent failures, realizing the automatic switching on according to conditions and raising the reliability and the safety of the power supply.

Description

Automatic protector of low voltage electrifield wire netting controlled by computer

The utility model relates to a kind of protective device of low voltage electric network, especially a kind of automatic safety device that utilizes micro-processor controlled low voltage electric network.

Low voltage electric network generally is meant 380 volts; power, the mains lighting supply line of 220 volts and 110 volts; along with the development of producing and the raising of living standards of the people; electricity is more and more closer with people's relation; because of all principles; but constantly take place with electrification; having a strong impact on the safety of people's life and property; for this reason; people's Live wires has been installed all protective devices in the road; as protector for circuit cut-off overload, under-voltage protection device and protective device of leakage current, these have played certain effect to the fail safe that improves electricity consumption.But,, still have generation with electrification though some occasion has been installed safeties because above-mentioned protective device sensitivity is lower.

The purpose of this utility model is that it is very high to design a kind of sensitivity, can be automatically to the short circuit in the low voltage electric network, open circuit, micro-processor controlled automatic protecting device that accident such as electric leakage is protected automatically.

The purpose of this utility model is achieved in that a kind of micro-processor controlled low no electrical network automatic protecting device, by current transformer, voltage sampling and leakage current inductor are formed, it is characterized in that: current transformer LH1, LH2, the output of LH3 is connected on interface circuit 1～6 end of microcomputer respectively, voltage sampling is received interface circuit 7～10 ends respectively, the output of leakage current inductor T is received 11 of interface circuit, 12 ends, reset button SB receives 13 of interface circuit, 14 ends, be connected to the status display circuit of forming by LED and R respectively between 16～22 ends of interface and 15 ends, the end of functional select switch SA is connected to 24 ends of interface circuit by control relay KM, 23 ends of the other end of functional select switch SA and interface circuit or 25 end in contact, the K of controlled relay K M control is serially connected on the electrical network output circuit.

Advantage of the present utility model is: owing to adopted computer technology; give full play to its automatically monitoring, judgement automatically, automatic checking, automatic error detection, the advantage of double counting repeatedly; can be to the overload in the circuit, short circuit, open circuit, fault such as electric leakage protects simultaneously; has very high selectivity and sensitivity; and can be " transient fault " or " permanent fault " by the automatic failure judgement of microcomputer; according to circumstances realize automatic reclosing; the reliability and the fail safe of power supply have been improved; reduced unnecessary power failure; simultaneously, installation and maintenance are convenient.

Fig. 1 is the utility model principle schematic.

Below in conjunction with accompanying drawing embodiment of the present utility model is further described.

As shown in Figure 1, current transformer LH1, LH2, LH3 are located at respectively on three-phase power line A, B, the C; Be used to monitor the actual current of every phase, the secondary output end of three current transformers is connected on interface circuit 1～6 end of microcomputer respectively; Phase voltage is connected on interface circuit 7～9 ends of microcomputer, and center line N is connected on 10 ends; All phase lines and center line all place among the leakage current reaction magnetic ring, and the induction coil output of leakage current inductor T is connected to interface circuit 11,12 ends of microcomputer; The end of functional select switch SA joins by 24 ends of control relay KM and interface circuit, the other end or with 25 end in contact, constitute automatic control circuit, or with 23 end in contact, remove system controlled by computer, and force the K switch closure of KM control; Reset button SB is connected to 13,14 ends of interface circuit, after just starting or line fault are got rid of, when needing micro computer monitoring, must press reset switch SB; Be connected to the status display circuit of forming by LED and R between 15 ends of interface circuit and 16～22 ends.

In the present embodiment, the maximum induced current of the inferior line of current transformer LH1, LH2, LH3 is 5A, and voltage sampling takes directly phase voltage to be introduced microcomputer interface 7～9 ends, and center line N introduces interface 10 ends.Microcomputer chip is selected 8031 chips for use.In order to determine the minimum working current of leakage current, the magnet ring outside at leakage current inductor T, be connected across on the center line N and phase line of end of gateway two of magnet ring, be connected to the leakage current sensitivity debug circuit of forming by hand push button S and load resistance R8, the resistance of R8 can allow the size of leakage current according to circuit, directly calculates with Ohm's law.

Claims

1, a kind of micro-processor controlled low voltage electric network automatic protecting device, by current transformer, voltage sampling, the leakage current inductor is formed, it is characterized in that: current transformer LH1, LH2, the output of LH3 is connected on interface circuit 1～6 end of microcomputer respectively, voltage sampling is received 7～10 ends of interface circuit respectively, the output of leakage current inductor T is received 11 of interface circuit, 12 ends, reset button SB is connected on 13 of interface circuit, 14 ends, be connected to the status display circuit of forming by LED and R respectively between 16～22 ends of interface and 15 ends, the end of functional select switch SA is connected to 24 ends of interface circuit by control relay KM, 23 ends of the other end of functional select switch and interface circuit or 25 end in contact, the K of controlled relay K M control is serially connected on the electrical network output circuit.

2, micro-processor controlled low voltage electric network automatic protecting device according to claim 1, it is characterized in that: the leakage current sensitivity debug circuit of being made up of hand push button S and load resistance R8 is located at the magnet ring outside of leakage current inductor T, and is connected across on the center line and phase line at two ends, gateway of magnet ring.