CN102012474A

CN102012474A - Interphase short circuit pre-detection process for coal mine high voltage and low voltage power lines

Info

Publication number: CN102012474A
Application number: CN201010292146XA
Authority: CN
Inventors: 陶作存
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-20
Filing date: 2010-09-20
Publication date: 2011-04-13

Abstract

The invention discloses an interphase short circuit pre-detection process for coal mine high voltage and low voltage power lines. An equivalent inductor L1 of a control transformer is connected between a phase A and a phase B; the inductor L1 is connected in parallel with each transformer; a first-side direct-current resistor R1 of the control transformer is connected in series with the inductor L1; a resistor R2 is connected in series between an A-phase insulation resistor and a B-phase insulation resistor; and a capacitor C1 is connected in series with an A-phase distribution capacitor and a B-phase distribution capacitor. The interphase short circuit pre-detection process for coal mine high voltage and low voltage power lines has the advantages of effectively preventing error-circuit power transportation, preventing accidents and guaranteeing the safe production.

Description

Colliery high-low pressure supply line phase fault pre-detection technology

Technical field

The present invention relates to the characterization processes of a kind of colliery electric power system, the high-low pressure supply line phase fault pre-detection technology of particularly a kind of colliery electric power system.

Background technology

The phase fault pre-detection is meant that power-supply unit to the load circuit, can detect the detection technique that has or not phase fault before not closing a floodgate.The manufacturer of the mining switch of present national neither one uses the short circuit pre-detection.The short-circuit protection that uses is after switch closes a floodgate power supply now, carries out the short trouble protection by the detection line size of current.If short trouble had taken place before not sending electricity circuit, the method for existing short-circuit detecting just can't not predicted short trouble before sending electricity.Only after sending electricity, there is short-circuit current to take place just can detect short trouble.Present switch short-circuit protection technology, it is can't be detected that short trouble has been arranged before circuit is not sending electricity, has only by after closing a floodgate, and short-circuit current occurred and just can carry out the fault separating brake.But this short-circuit current can form spark and blast, causes the secondary fault of electric power system, and fault is enlarged.Unfavorable to Safety of Coal Mine Production.

Summary of the invention

Technical matters to be solved by this invention is: the phase fault before closing a floodgate is judged, is prevented from the circuit of the fault that is short-circuited is closed a floodgate.

In order to solve the problems of the technologies described above, the technical solution used in the present invention is:

In the high-low pressure supply line of colliery, the alternate parallel connection relation that can equivalence becomes inductance L 1, capacitor C 1, resistance R 1 of load-side any two.Wherein L1 is the equivalent inductance of each switch control transformer of load-side.C1 is the equivalent capacity of two-phase circuit.R1 is two alternate resistance.When at two alternate additional alternating currents that frequency is suitable, make the load-side loop be in concussion state in parallel, can obtain the value of resistance R 1 this moment by the current/voltage of measuring alternating current.Be two alternate resistance, finish the line to line fault pre-detection.

By alternating current, measure the alternate resistance of two-phase to line load side two alternate additional changeable frequencies.Finish the phase fault pre-detection.

Beneficial effect of the present invention: colliery high-low pressure supply line phase fault pre-detection can effectively prevent to send electricity to faulty line, and the accident that prevents takes place, and guarantees safe production.

Description of drawings

Fig. 1, the switch preceding synoptic diagram that do not close a floodgate;

Fig. 2, electric circuit inspection schematic diagram;

Fig. 3, phase measurements isoboles.

Embodiment

The China's coal-mine power supply is the three-phase isolated neutral system.Before switch does not close a floodgate load as shown in Figure 1, T1, T2 are the control transformer of next stage switch among the figure, the quantity of this transformer is uncertain in actual applications, and wiring also is at random, promptly T1 can be connected on A, C two-phase and also can be connected on B, C two-phase.R1, R2, R3 are the insulation resistances of every phase circuit, and this resistance is indefinite, for the 660V electric power system all greater than 11K.The 1140V electric power system is greater than 20K.C1, C2, C3 are respectively every distributed capacitance relatively.This distributed capacitance is determined by Route Length, changes between 0～1uF.

If measure between the AB two-phase whether short circuit then circuit equivalent become Fig. 2.L1 is the control transformer equivalent inductance among the figure, is the parallel connection of each transformer.R1 is the primary side direct current resistance of control transformer, and mining switching mode power supply transformer primary side direct current resistance is all less than 250 Ω, and this value can be ignored.R2 is A phase and the B series connection of insulation resistance mutually.C1 is A phase and the B series connection of distributed capacitance mutually.By circuit base knowledge as can be known, apply the alternating current of a changeable frequency between A, B two-phase, when frequency rose gradually from 0Hz, circuit can present from inductive circuit and gradually change into capacitive circuit.Be resonant condition when being between perception and the capacitive, this moment, circuit was in Resistance states, can calculate resistance value by current effective value and the voltage effective value of measuring alternating current.The resistance of R1＞20K Ω under the normal condition, resistance can be less than 1K Ω when short circuit takes place, and whether can detect thus has short trouble.

Detect schematic diagram such as Fig. 3, L1, R1, C1 are the equivalent parameterss between A, the B two-phase among the figure, after the R2 series connection, behind the alternating current of an additional changeable frequency between AC1 and the ground, the phase place between detection P1, the P2 is promptly known and is inductive circuit or capacitive circuit under this frequency.When phase place is identical, be resistance states, measure the value of P1, P2,, promptly can judge whether short trouble thus by calculating the size that can draw R1 resistance.

Claims

1. colliery high-low pressure supply line phase fault pre-detection technology is characterized in that, any two alternate equivalences of line load side is become the parallel connection relation of inductance L 1, capacitor C 1, resistance R 1; Wherein L1 is the equivalent inductance of each switch control transformer of load-side, C1 is the equivalent capacity of two-phase circuit, R1 is two alternate resistance, when at two alternate additional alternating currents that frequency is suitable, make the load-side loop be in concussion state in parallel, can obtain the value of resistance R 1 this moment by the current/voltage of measuring alternating current; Be two alternate resistance, finish the line to line fault pre-detection.