A kind of all-fiber on-line monitoring system for high voltage cable
Technical field
The present invention relates to a kind of on-line detecting system, especially a kind of all-fiber on-line monitoring system for high-tension cable.
Background technology
At present, high-voltage cable insulating localization of fault technology mainly adopts the impulse method based on off-line test, when producing cable fault, first power-off, then untied from system by cable line, recycling pulse signal carries out cable fault localization, based on the parameter model of cable line, by scene, pulse signal is applied to cable, then travel-time and velograph calculate trouble spot distance in the cable by electric current and voltage travelling wave signal.There is obvious shortcoming in the method, after cable breaks down, needs cable interface is out of service, then fault measuring equipment is transported to scene, arranges measuring equipment and wiring, could start to measure.
In addition, based on the synchronous high-tension cable On-line Fault location of GPS, due to the poor synchronization of gps clock, be difficult to accurate location, and the location technology of clock synchronous based on Optical Fiber Transmission, require consistent to two sensors module end fiber lengths of locating device, this makes troubles to Practical Project construction, add optical cable cost, the layout for locating device brings restriction simultaneously.
When cable metal sheath circulation occurs abnormal, the loss heating of cable insulation localized hyperthermia can be caused, accelerate insulation ag(e)ing, reduce cable serviceable life, time serious, cause cable to occur directly to puncture earth fault, make cable jacket damaged, occur multipoint earthing phenomenon, after oversheath breakage, protective metal shell is corroded, both add the probability that major insulation body is aging, easily bring out shelf depreciation and electric branch again; So indirect monitoring cable metal sheath Atmospheric Circulation Anomalies situation can be carried out by the monitoring of cable temperature.
Summary of the invention
The technical problem to be solved in the present invention is: the problem that in prior art, the location of causing is inaccurate because the length difference of connecting fiber brings delay variation, and need cable interface out of service, can not on-line checkingi, the monitoring simultaneously for cable metal sheath Atmospheric Circulation Anomalies situation also lacks effective means.
In order to solve the problems of the technologies described above, the invention provides a kind of all-fiber on-line monitoring system for high voltage cable, comprise two current signal modulation terminals, two current signal demodulation terminals, an optical fiber distributed temperature demodulation terminal, two connecting fibers, optical path switch module, optical-fiber time-delay measuring appliance, microprocessor, optical cable snap close and temperature measuring optical cables; Two current signal modulation terminals carry out current signal collection for the two ends being connected to cable to be detected, and be two ways of optical signals by the two-way current signal modulation collected, then transfer to two optical signal input of optical path switch module by two connecting fibers; Two connecting fibers switchings are connected to the measuring junction of optical-fiber time-delay measuring appliance or the input end of two current signal demodulation terminals by Microprocessor S3C44B0X optical path switch module; The two piece connecting fibers of optical-fiber time-delay measuring appliance to access carry out the Delay that time-delay analysis obtains two connecting fibers, and Delay is sent to microprocessor; The optical signal demodulation of input is electric signal by two current signal demodulation terminals, then sends after electric signal AD conversion into microprocessor; Temperature measuring optical cable along cable laying to be detected, and is fixed on cable to be detected by optical cable snap close; Temperature measuring optical cable is connected to optical fiber distributed temperature demodulation terminal; The temperature information that optical fiber distributed temperature demodulates temperature measuring optical cable perception sends into microprocessor.
Adopt current signal modulation terminal can real-time online sensed current signal, and without the need to cable interface is out of service, real-time and the detection efficiency of cable detection can be improved; Adopt optical path switch module can send into optical-fiber time-delay measuring appliance or current signal demodulation terminal according to detecting the light signal needing current signal modulation terminal to send, thus make time delay detection and fault detect share connecting fiber, save system cost; Adopt optical-fiber time-delay measuring appliance can detect the signal time delay caused by connecting fiber as required, thus effectively improve the precision of localization of fault; Temperature measuring optical cable is adopted to carry out Real-Time Monitoring to the temperature of cable, thus indirect monitoring cable metal sheath Atmospheric Circulation Anomalies situation, avoid occurring considerable safety fault.
As further restriction scheme of the present invention, current signal modulation terminal comprises current sensor and electrical to optical converter; Current sensor is used for gathering the current signal of cable under test, and the current signal collected is sent to electrical to optical converter; Current signal is converted to light signal by electrical to optical converter, and transfers to the optical signal input of optical path switch module by connecting fiber.Adopt current sensor can detect current signal on tested high-tension cable and fault traveling wave by real-time online, and be non-contact measurement, security performance is higher.
As further restriction scheme of the present invention, current signal demodulation terminal comprises photoelectric commutator and AD converter; The light signal that optical path switch module exports is converted to electric signal by photoelectric commutator, and sends into microprocessor after carrying out AD conversion by AD converter.
Scheme as a further improvement on the present invention, current signal demodulation terminal also comprises a signal conditioning circuit be connected between photoelectric commutator and AD converter; The electric signal that photoelectric commutator exports is adjusted to the working range being adapted to AD converter by signal conditioning circuit.Adopt signal conditioning circuit the electric signal that photoelectric commutator exports can be adjusted to the working range being adapted to AD converter, improve the reliability that positioning system detects.
As further restriction scheme of the present invention, optical-fiber time-delay measuring appliance is optical time domain reflectometer.
As further restriction scheme of the present invention, optical path switch module is made up of the first controlled 1 × 2 photoswitch, the second controlled 1 × 2 photoswitch and the 3rd controlled 1 × 2 photoswitch; 1 port of the first controlled 1 × 2 photoswitch and the second controlled 1 × 2 photoswitch is connected to the output terminal of two current signal modulation terminals respectively by two connecting fibers, all have Single port to be connected to the input end of corresponding current signal demodulation terminal in 2 ports of the first controlled 1 × 2 photoswitch and the second controllable light 1 × 2 switch; 2 ports of the 3rd controlled 1 × 2 photoswitch are connected to the another port in 2 ports of the first controlled 1 × 2 photoswitch and the second controllable light 1 × 2 switch respectively, and 1 port of the 3rd controlled 1 × 2 photoswitch is connected to the measuring junction of optical-fiber time-delay measuring appliance.Adopt three controlled 1 × 2 photoswitches can realize the controlled switching of light path, and utilize the 3rd controlled 1 × 2 photoswitch that the two-way optical fiber of input is switched to optical-fiber time-delay measuring appliance successively, the optical-fiber time-delay measuring appliance using expensive multi input end can be avoided, effectively reduce system cost.
Scheme as a further improvement on the present invention, also comprises a display screen be connected with microprocessor.Utilize display screen can show abort situation in real time.
Scheme as a further improvement on the present invention, also comprises an alarm be connected with microprocessor.Adopting alarm can give the alarm in time when monitoring high temperature dot, reminding monitor staff to investigate rapidly.
Scheme as a further improvement on the present invention, optical cable snap close comprises to be pricked bar, be arranged on the socket of bundle bar one end and be connected to the cutting of the bundle bar other end; In socket, be provided with main ratchet, cutting be provided with corresponding with main ratchet from ratchet; The semi-circular shape embedded for temperature measuring optical cable is provided with protruding in the stage casing pricking bar.Adopt semi-circular shape projection conveniently can fix the position of temperature measuring optical cable, after preventing from tying up, occur position moving influence measurement effect.
Scheme as a further improvement on the present invention, is provided with antislip cog inside the circle pricking bar.Adopt antislip cog effectively can prevent pricking bar and tie up the rear problem occurring rotating around cable to be detected, enhance the locating effect of temperature measuring optical cable.
Beneficial effect of the present invention is: (1) adopts current signal modulation terminal can real-time online sensed current signal, and without the need to cable interface is out of service, can improve real-time and the detection efficiency of cable detection; (2) optical path switch module is adopted can to need first by the time delay of optical fiber latency measurement device measurement two-way optical fiber according to detecting, the demodulation of current signal is carried out afterwards by electric current signal receiving terminal, thus make time delay detection and fault detect share connecting fiber, save system cost; (3) adopt optical-fiber time-delay measuring appliance can detect the signal time delay caused by connecting fiber as required, thus effectively improve the precision of localization of fault; (4) temperature measuring optical cable is adopted to carry out Real-Time Monitoring to the temperature of cable, thus indirect monitoring cable metal sheath Atmospheric Circulation Anomalies situation, avoid occurring considerable safety fault.
Accompanying drawing explanation
Fig. 1 is electrical block diagram of the present invention;
Fig. 2 is the structural representation of optical path switch module of the present invention;
Fig. 3 is the fault traveling wave schematic diagram that the present invention detects acquisition;
Fig. 4 is optical cable buckle structure schematic diagram of the present invention.
Embodiment
As shown in Figure 1, all-fiber on-line monitoring system for high voltage cable provided by the invention comprises: two current signal modulation terminals, two current signal demodulation terminals, an optical fiber distributed temperature demodulation terminal, two connecting fibers, optical path switch module, optical-fiber time-delay measuring appliance, microprocessor, optical cable snap close, display screen, alarm and temperature measuring optical cables.
Wherein, two current signal modulation terminals carry out current signal collection for the two ends being connected to cable to be detected, and be two ways of optical signals by the two-way current signal modulation collected, then transfer to two optical signal input of optical path switch module by two connecting fibers; Two connecting fibers switchings are connected to the measuring junction of optical-fiber time-delay measuring appliance or the input end of two current signal demodulation terminals by Microprocessor S3C44B0X optical path switch module; The two piece connecting fibers of optical-fiber time-delay measuring appliance to access carry out the Delay that time-delay analysis obtains two connecting fibers, and Delay is sent to microprocessor; The optical signal demodulation of input is electric signal by two current signal demodulation terminals, then sends after electric signal AD conversion into microprocessor; Temperature measuring optical cable along cable laying to be detected, and is fixed on cable to be detected by optical cable snap close; Temperature measuring optical cable is connected to optical fiber distributed temperature demodulation terminal, and the temperature information that optical fiber distributed temperature demodulates temperature measuring optical cable perception sends into microprocessor; Microprocessor carries out analytical calculation according to the delayed data of input and the electric signal of AD conversion, obtains fault location information; Microprocessor judges whether to occur that localized hyperthermia is dangerous according to the temperature information that optical fiber distributed temperature demodulation terminal inputs; Display screen is all connected with microprocessor with alarm.
Current signal modulation terminal generally comprises current sensor and electrical to optical converter; Current sensor is used for gathering the current signal of cable under test, and the current signal collected is sent to electrical to optical converter; Current signal is converted to light signal by electrical to optical converter, and transfers to the optical signal input of optical path switch module by connecting fiber.
Current signal demodulation terminal generally comprises photoelectric commutator, signal conditioning circuit and AD converter.The light signal that optical path switch module exports is converted to electric signal by photoelectric commutator, and sends into microprocessor after carrying out AD conversion by AD converter; Signal conditioning circuit is connected between photoelectric commutator and AD converter; The electric signal that photoelectric commutator exports is adjusted to the working range being adapted to AD converter by signal conditioning circuit.
Optical fiber distributed temperature demodulation terminal generally comprises laser instrument, photo-coupler, filtering optical splitter, photoelectric commutator, signal conditioning circuit, AD converter and signal processor.Laser instrument sends sensed light signal by photo-coupler to temperature measuring optical cable; Photoelectric commutator, filtering optical splitter, signal conditioning circuit, AD converter and signal processor are used for carrying out demodulation process to the light signal that temperature measuring optical cable feeds back dorsad.
This all-fiber on-line monitoring system for high voltage cable is when carrying out localization of fault work, first utilize optical path switch module two connecting fibers to be switched and be connected to optical-fiber time-delay measuring appliance, measure by optical-fiber time-delay measuring appliance the Signal transmissions time delay T1 and T2 that two connecting fiber L1 and L2 cause separately respectively;
Two connecting fibers switchings are connected to two current signal demodulation terminals by recycling optical path switch module respectively, send into microprocessor after carrying out optical signal demodulation by current signal demodulation terminal and carry out fault analysis, obtain fault traveling wave and transfer to the duration t1 of microprocessor from high-tension cable on the left of trouble spot and connecting fiber L1 and transfer to the duration t2 of microprocessor from high-tension cable on the right side of trouble spot and connecting fiber L2;
Last basis following formulae discovery trouble spot apart from the distance of check point on the left of high-tension cable to be measured is:
X=(L-V×(t1-t2+T2-T1))/2
In formula, L is the length of cable about high-tension cable to be measured between two check points, and V is failed row velocity of wave propagation.
As shown in Figure 2, optical path switch module is made up of the first controlled 1 × 2 photoswitch, the second controlled 1 × 2 photoswitch and the 3rd controlled 1 × 2 photoswitch; 1 port of the first controlled 1 × 2 photoswitch and the second controlled 1 × 2 photoswitch is connected to the output terminal of two current signal modulation terminals respectively by two connecting fibers, all have Single port to be connected to the input end of corresponding current signal demodulation terminal in 2 ports of the first controlled 1 × 2 photoswitch and the second controllable light 1 × 2 switch; 2 ports of the 3rd controlled 1 × 2 photoswitch are connected to the another port in 2 ports of the first controlled 1 × 2 photoswitch and the second controllable light 1 × 2 switch respectively, and 1 port of the 3rd controlled 1 × 2 photoswitch is connected to the measuring junction of optical-fiber time-delay measuring appliance.
As shown in figs. 1 and 3, before localizing faults is measured, first controlled 1 × 2 photoswitch of Microprocessor S3C44B0X optical path switch module, the second controlled 1 × 2 photoswitch and the 3rd controlled 1 × 2 photoswitch, two connecting fibers are switched successively and is connected to fiber delay time measuring appliance, thus the time delay that two connecting fiber L1 and L2 cause is measured, obtaining time delay value is respectively T1 and T2, and by fiber delay time measuring appliance, T1 and T2 is sent to microprocessor and carries out stored record; And then control optical path switch module by two ways of optical signals switch input to two current signal modulation terminals respectively.After latency measurement, Microprocessor S3C44B0X optical path switch module, switches to fault traveling wave signal monitoring state by light path.
When cable to be detected breaks down, there will be the fault traveling wave shown in Fig. 3.Now the fault traveling wave signal treated on detection streamer is carried out Real-time Collection by current sensor, and by electrical to optical converter, the fault traveling wave signal of collection is converted to light signal, and transfer to the first controlled 1 × 2 photoswitch of optical path switch module and 1 port optical signal input part of the second controlled 1 × 2 photoswitch by connecting fiber; Again by the first controlled 1 × 2 photoswitch and second controlled 1 × 2 photoswitch of Microprocessor S3C44B0X optical path switch module, the light signal of two connecting fiber L1 and L2 conveying is switched and inputs to photoelectric commutator, by photoelectric commutator, the light signal received is converted to electric signal; By signal conditioning circuit, the electric signal that photoelectric commutator exports is nursed one's health again, this electric signal is gathered completely by AD converter; Microprocessor processes the signal after AD conversion.Supposing that microprocessor obtains according to the signal analysis after AD conversion the duration that fault traveling wave transfers to microprocessor from the high-tension cable of trouble spot the right and left and two connecting fiber L1 and L2 is respectively t1 and t2, failed row velocity of wave propagation is V, the length of cable to be detected is L, calculates trouble spot C to the current signal modulation termination detection point distance in left side to be by microprocessor:
X=V×(t1-T1)(1)
Calculating trouble spot C to the current signal modulation termination detection point distance on right side is:
L-X=V×(t2-T2)(2)
Can obtain according to formula (1) and (2) again:
X=(L-V×(t1-t2+T2-T1))/2(3)
Thus calculate the size of trouble spot C to the current signal modulation termination detection point distance X in left side, and shown in real time by display screen.
As shown in Figure 4, optical cable snap close of the present invention comprises bundle bar 1, is arranged on the socket 4 pricking bar 1 one end and the cutting 5 being connected to bundle bar 1 other end; In socket 4, be provided with main ratchet, cutting 5 be provided with corresponding with main ratchet from ratchet; The semi-circular shape projection 2 embedded for temperature measuring optical cable is provided with in the stage casing pricking bar 1; Antislip cog 3 is provided with inside the circle pricking bar 1.When fixing temperature measuring optical cable, temperature measuring optical cable is embedded in semi-circular shape projection 2, then bundle bar 1 is banded on cable to be detected, make the main ratchet in socket 4 fixing with being meshed from ratchet in cutting 5.When microprocessor receive temperature measuring optical cable transmission return temperature signal and analyze existing localized hyperthermia time, then control alarm report to the police, remind monitor staff enter rapidly
Row investigation.