Background technology
Because mobile base station and outdoor base station are in the higher environment of Lightning Electromagnetic Pulse degree of exposure, Lightning Electromagnetic Pulse can induce dangerous overvoltage on the DC line of communication power supply, threaten the safety of DC port equipment; In addition, when lightning current hit the outside lightning protection device of base station or near the metal structures the base station, lightning current can be directed into the earth and release, and went into the lightning current on ground and the earth mat current potential of base station can be raised, and also will threaten the safety of DC port equipment.Therefore need a DC lightning prevention unit, be used for DC port equipment is protected.
Present DC lightning prevention unit mainly adopts the modular lightning protection device of guide tracked installation, it comprises a lightning protection main circuit and a warning circuit, and this warning circuit is divided into signal sample circuit and signaling conversion circuit, wherein signal sample circuit is used for fuse malfunction on the lightning protection main circuit is sampled, and signaling conversion circuit is used for sampled signal is converted into the dry contact alarm signal.
But in the DC lightning prevention unit of prior art, the design more complicated of its signal sample circuit will certainly increase cost.And signaling conversion circuit is not protected signal sample circuit, damages triode when residual voltage is higher in the signal sample circuit easily, makes fault-signal can not be converted into dry contact alarm, causes warning circuit to lose efficacy.In addition, signal sample circuit does not design lightning protection main circuit malfunction indicator lamp in the prior art, and dry contact alarm output has only normally closed a kind of.
Therefore need a kind of new DC lightning prevention unit and warning circuit thereof, thereby reduce cost, and further improve the security performance of warning circuit to simplify warning circuit.
Summary of the invention
The object of the present invention is to provide a kind of DC lightning prevention unit, be intended to solve design complexity, cost height that the DC lightning prevention unit of prior art exists, and the lower problem of fail safe.
The present invention also aims to provide the warning circuit in a kind of DC lightning prevention unit, to solve the above-mentioned problems in the prior art better.
In order to realize goal of the invention, described DC lightning prevention unit comprises the lightning protection main circuit, and the warning circuit that links to each other with described lightning protection main circuit, described warning circuit comprises at least one road signal sample circuit, a signal transfering circuit and a signaling conversion circuit, described at least one road signal sample circuit comprises a diode and two resistance, and the anode of described diode links to each other with the tie point of described two resistance;
The negative electrode of an end of the non-described tie point of a resistance and described diode is as two inputs of signal sample circuit in described two resistance, and links to each other with described lightning protection main circuit;
An end of the non-described tie point of another resistance is as the output of signal sample circuit in described two resistance, and links to each other with signal transfering circuit.
Preferably, comprise at least one line structure between the positive and negative row of described lightning protection main circuit, described line structure is made up of at least one slow blow out fuse and at least one piezo-resistance.
Preferably, comprise two line structures between the positive and negative row of described lightning protection main circuit, each line structure links to each other with three piezo-resistances after the same parallel connection after by described two slow blow out fuse parallel connections and constitutes.
Preferably, the input of described at least one road signal sample circuit links to each other with a branch road of described lightning protection main circuit respectively, one of them input is that diode cathode links to each other with the negative row of lightning protection main circuit by slow blow out fuse, and another input links to each other with the just row of lightning protection main circuit.
Preferably, the diode of described at least one road signal sample circuit is a light-emitting diode.
Preferably, described signal transfering circuit comprises two resistance and a triode, described two resistance series connection also is connected between the base stage and emitter of described triode, the tie point of two resistance links to each other as the input of signal transfering circuit and with the output of signal sample circuit, and the collector electrode of described triode links to each other with the input of signaling conversion circuit.
Preferably, described signaling conversion circuit comprises a relay, and described relay is the dry contact alarm signal with the conversion of signals that signal transfering circuit transmits, and output.
Preferably, described triode and relay two ends are parallel with a transient voltage inhibition diode.
Preferably, described relay two ends also are parallel with a transient voltage and suppress diode.
In order to realize goal of the invention better, warning circuit in the described DC lightning prevention unit links to each other with lightning protection main circuit in the DC lightning prevention unit, it comprises at least one road signal sample circuit, a signal transfering circuit and a signaling conversion circuit, described at least one road signal sample circuit comprises a diode and two resistance, and the anode of described diode links to each other with the tie point of described two resistance;
The negative electrode of an end of the non-described tie point of a resistance and described diode is as two inputs of signal sample circuit in described two resistance, and links to each other with described lightning protection main circuit;
An end of the non-described tie point of another resistance is as the output of signal sample circuit in described two resistance, and links to each other with signal transfering circuit.
In the DC lightning prevention unit of the present invention, its warning circuit comprises at least one road signal sample circuit, and this signal sample circuit only comprises a diode and two resistance, has therefore greatly simplified the design of warning circuit, has reduced cost; In addition, the present invention designs lightning protection main circuit malfunction indicator lamp in signal sample circuit, and often provide at the dry contact alarm output facet open, normally closed dual mode, further perfect this DC lightning prevention unit.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
DC lightning prevention unit of the present invention comprises the lightning protection main circuit, and coupled warning circuit, this warning circuit comprises at least one road signal sample circuit, a signal transfering circuit and a signaling conversion circuit, and wherein signal sample circuit only comprises a diode and two resistance, its structure has obtained simplifying greatly than prior art, thereby reduced the volume of DC lightning prevention unit, be easy for installation and maintenance, reduced cost.
Fig. 1 shows the outward appearance of DC lightning prevention unit among the present invention, and it has an indicator light and siren, is used for fault is alarmed indication.This lightning protection unit links to each other with power supply, and as seen from the figure, the V+ connected system is just arranged, the negative row of V-connected system, PE connected system PE row.
The internal circuit configuration of this DC lightning prevention unit comprises lightning protection main circuit and warning circuit two parts, and it will be elaborated respectively in Fig. 2 and Fig. 3.
Fig. 2 shows the structure of the lightning protection main circuit of DC lightning prevention unit among the present invention.Consistent with Fig. 1, the negative row of V-welding system, the V+ welding system is just arranged, J1 welding system PE row, just arranging and PE between be discharge tube G1, this system typically can be direct current 48V system.
Comprise at least one line structure between the positive and negative row of this lightning protection main circuit, this line structure is made up of at least one slow blow out fuse and at least one piezo-resistance.
In the embodiment shown in Figure 2, between the just row of this lightning protection main circuit and the negative row is the two-way parallel-connection structure, every road comprises the piezo-resistance of three parallel connections, link to each other with the slow blow out fuse of two parallel connections, be specially: in the first via, three piezo-resistance RV1, RV2, RV3 parallel connection, two slow blow out fuse F1, F2 parallel connection; In the second the tunnel, three piezo-resistance RV4, RV5, RV5 parallel connection, two slow blow out fuse F3, F4 parallel connection.
Fig. 3 shows the structure of the warning circuit of DC lightning prevention unit among the present invention.Among the present invention, warning circuit comprises three parts: a signal sample circuit, a signal transfering circuit, a signaling conversion circuit.Wherein:
(1) signal sample circuit is used for fuse malfunction on the lightning protection main circuit is sampled, and sends the fault-signal that collects to signaling conversion circuit by signal transfering circuit.
This signal sample circuit can be multichannel (at least one road), and every road comprises a diode and two resistance, in one embodiment, this typical of diodes can be light-emitting diode, be used for the lightning protection main circuit is carried out faulty indication.As Fig. 3, first via signal sample circuit comprises light-emitting diode D1, its anode links to each other with the tie point of resistance R 1, R3, the other end of its negative electrode and R1 links to each other as two inputs of this road signal sample circuit and with the lightning protection main circuit, and the other end of R3 links to each other as the output of this road signal sample circuit and with signal transfering circuit; The second road signal sample circuit comprises light-emitting diode D2, its anode links to each other with the tie point of resistance R 2, R4, the other end of its negative electrode and R2 links to each other as two inputs of this road signal sample circuit and with the lightning protection main circuit, and the other end of R2 links to each other as the output of this road signal sample circuit and with signal transfering circuit.This sample circuit is compared with the sample circuit of prior art, and is very succinct.
In the embodiment of Fig. 2 and Fig. 3, the input of signal sample circuit links to each other with a branch road of lightning protection main circuit respectively, one of them input is that diode (for example D1) negative electrode links to each other with the negative row of lightning protection main circuit by slow blow out fuse, and another input R1 links to each other with the just row of lightning protection main circuit.
(2) signal transfering circuit comprises two resistance (R5, R6) and a triode Q1, these two resistance R 5, R6 series connection, and be connected between the base stage and emitter of triode Q1, the tie point of resistance R 5, R6 links to each other as the input of signal transfering circuit and with the output of signal sample circuit, and the collector electrode of triode Q1 links to each other with the input of signaling conversion circuit.
(3) signaling conversion circuit comprises a relay R LY, is used for the signal with the signal transfering circuit transmission, also is that the fuse malfunction is converted to a dry contact alarm signal on the lightning protection main circuit.
In the embodiment shown in fig. 3, this relay R LY links to each other with triode Q1, both two ends then are parallel with transient voltage and suppress diode (Transient Voltage Suppressors, TVS) D4, and this relay R LY two ends also are parallel with a transient voltage and suppress diode D3.Wherein, transient voltage suppresses diode D4 and is used for triode Q1 is protected, and prevents that it is broken down by high-voltage.When among the present invention fuse malfunction on the lightning protection main circuit being converted to a dry contact alarm signal, often have open, normally closed dual mode.
The present invention utilizes in the process of this lightning protection unit lightning protection, and the mechanism of utilizing warning circuit to protect is:
When the lightning protection unit operate as normal, 2 ends of indicator light D1/D2 are electronegative potential, produce a potential difference so at indicator light D1/D2 two ends, and indicator light is bright." 1 " of triode Q1 and " 2 " potential difference are zero, not conducting of triode, thus relay R LY is failure to actuate, and does not produce alarm signal;
Lightning protection main circuit in lightning protection unit breaks down and causes short circuit, after slow blow out fuse (F1, F2, or F3, the F4) fusing, two indicator light D1/D2's " 2 " end is high voltage, corresponding indicator light goes out." 1 " of triode Q1 and " 2 " terminal voltage official post triode Q1 conducting, relay R LY action produces the dry contact alarm signal.
Because alarm adopts circuit power directly to get between positive and negative row; for having added transient voltage, the protection sample circuit suppresses diode D4; when lightning protection unit is released lightning current and when producing high pressure between V+ and V-; D4 can effectively reduce the voltage on relay R LY coil and the Q1 circuit, thereby avoids the Q1 high-voltage breakdown.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.