CN114460523A - Straight-through current transformer disconnection and polarity inspection system and control method thereof - Google Patents
Straight-through current transformer disconnection and polarity inspection system and control method thereof Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/72—Testing of electric windings
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- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
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Abstract
The invention discloses a cross-core current transformer disconnection and polarity inspection system and a control method thereof, wherein the cross-core current transformer disconnection and polarity inspection system comprises a plurality of controllable pulse generating circuits and a plurality of Hall sensors, wherein secondary output terminals of a cross-core Current Transformer (CT) are positively penetrated into the Hall sensors; the multi-path selector switch selection circuits SWA, SWB and SWC are used for respectively controlling the frequency and amplitude of output pulses of all the controllable pulse generation circuits, and the SWC is used for gating one Hall sensor to output; the switching control circuit controls and selects one controllable pulse generating circuit to output pulses; the frequency control circuit and the amplitude control circuit respectively control the frequency and the amplitude of the output pulse and shape the output pulse; the data acquisition conversion circuit is connected with the multi-path selector switch selection circuit and is responsible for signal processing and acquisition of the recovery pulse; and a core control module. The invention can realize the disconnection detection and polarity detection of a plurality of feedthrough transformers on the premise of not influencing the normal monitoring of the feedthrough transformers, and has high detection efficiency and high precision.
Description
[ technical field ] A method for producing a semiconductor device
The invention belongs to the technical field of power systems, and particularly relates to a wire breakage and polarity inspection system of a feed-through current transformer and a control method thereof.
[ background of the invention ]
In an electric power system, a feedthrough Current Transformer (CT) is widely used, for example, to detect zero sequence current of the electric power system, leakage current of equipment, unbalanced current, and the like. Under the application condition, under the normal operation condition of primary equipment, the primary current synthetic magnetic flux of the core-through current is zero, so that the secondary current is also zero. The feedthrough CT will only have an output current if there is a primary device failure. When the cross-core CT has a secondary wire break or a wire break inside the coil due to some reasons, the secondary current is also zero, so that the cross-core CT cannot be distinguished from normal equipment operation, and therefore the wire break detection of the cross-core CT is difficult; meanwhile, since the cross-core CT has no current when normal, if the polarity (end with the same name) of the CT is connected in error, some application errors (such as zero sequence current direction determination in relay protection) can be caused, and therefore, the polarity detection of the cross-core CT is also important.
In the prior art, a manual detection mode is adopted for the broken line detection and polarity detection of the cross-core CT, as shown in fig. 1, under the condition that a primary loop of the CT is powered off, an alternating current is applied to the primary loop through a current source, an ammeter is penetrated into a secondary loop, and whether the cross-core CT is broken or not is judged through the existence of the detection current; as shown in fig. 2, the primary circuit is shocked by a battery (or a direct current power supply) to generate pulses, the secondary circuit is connected with a direct current swing needle type voltmeter, and the polarity (the same name end) is judged according to the direction of the swing needle. The method adopts a manual mode for detection, has low efficiency and high labor cost, and can not detect the CT disconnection and polarity abnormality of primary equipment during working.
In the prior art, an on-line detection method is adopted, as shown in fig. 3, a high-order harmonic is applied to a through-type CT through a coil, whether a secondary circuit has the high-order harmonic is detected to judge whether the through-type CT is broken, the high-order harmonic is generated by a transformer open circuit judging device and applied to the coil of the CT, and whether a harmonic current in a current transformer exists or not is detected to judge whether the CT is open circuit or not. Although the method is online, harmonic waves can interfere other secondary equipment, and meanwhile, due to different parameters of different CTs, multi-CT inspection cannot be realized, only one CT is provided with an open-circuit monitoring device, so that the cost is high and the efficiency is low.
Therefore, it is desirable to provide a new system for inspecting the disconnection and polarity of the feedthrough current transformer and a control method thereof to solve the above problems.
[ summary of the invention ]
The invention mainly aims to provide a system for inspecting the disconnection and polarity of a feedthrough current transformer, which can realize the disconnection detection and polarity detection of a plurality of feedthrough transformers on the premise of not influencing the normal monitoring of the feedthrough transformers and has high detection efficiency and high precision.
The invention realizes the purpose through the following technical scheme: a cross-core current transformer disconnection and polarity inspection system comprises
The pulse of the plurality of controllable pulse generating circuits KCP is output to the primary side of the straight-through mutual inductor CT;
the Hall sensors HR are responsible for pulse recovery and measurement, the number of the Hall sensors HR is the same as that of the controllable pulse generating circuits KCP, and secondary output terminals of the cross-core mutual inductor CT penetrate into the Hall sensors HR in the forward direction;
the multi-channel switch selection circuits SWA, SWB and SWC are used for controlling the frequency of pulses output by all the controllable pulse generation circuits KCP, controlling the amplitude of the pulses output by all the controllable pulse generation circuits KCP by the SWB and gating the output of a corresponding Hall sensor HR by the SWC;
the switching control circuit SWMD controls and selects one of the controllable pulse generating circuits KCP to output pulses;
the frequency control circuit FCMD and the amplitude control circuit VCMD respectively control the frequency and the amplitude of the output pulse and shape the output pulse;
the data acquisition and conversion circuit ADIMD is connected with the multi-path switch selection circuit SWC and is responsible for signal processing and acquisition of the recovery pulse; and
and the core control module is electrically connected with the switching control circuit SWMD, the frequency control circuit FCMD, the amplitude control circuit VCMD and the data acquisition and conversion circuit ADIMD.
Furthermore, the data acquisition and conversion circuit ADIMD internally comprises a low-pass filter, an anti-interference circuit and an ADC acquisition circuit thereof.
Furthermore, the system also comprises a power supply for supplying power to the core control module and a human-computer interaction system communicated with the core control module.
Further, the core control module is in communication with an external power monitoring system.
Furthermore, a pulse output terminal of the controllable pulse generating circuit KCP passes through the primary side aperture of the feedthrough transformer through a wire, and the transmission direction is the same as the current specified direction of the primary current carrier.
Further, a lead wire of the secondary output terminal P1 of the feedthrough transformer CT is inserted into the current hall sensor in the forward direction, and an outgoing wire is connected to a load and then connected to the secondary output terminal P2 of the feedthrough transformer CT.
Another objective of the present invention is to provide a method for controlling the disconnection and polarity inspection system of the feedthrough current transformer, which comprises
S1) the main routine is started;
s2) initializing parameters and a system;
s3) reading the number N of patrol CTs, and setting a patrol serial number i to 0;
s4) executing the open circuit inspection logic of the CTi;
s5) executing polarity patrol logic for the CTi;
s6) sets i to i +1, determines whether i is larger than N, and if so, returns to step S3), and if not, returns to step S4).
Further, the open circuit inspection logic in the step S4) includes: firstly, the fundamental current IVi of the cross-core mutual inductor CT is judged0If the current is larger than the CT no-flow threshold value, quitting the disconnection polling logic if the current is larger than the CT no-flow threshold value, otherwise, performing disconnection detection; making CT carry out self-adaptive learning logic to obtain pulse output parameter CT [ i][0]、CT[i][1]And CT [ i][2](ii) a According to the parameter CT [ i][1]Control controllable pulse generating circuitKCP output amplitude according to parameter CT [ i ]][2]Controlling the output frequency of the controllable pulse generating circuit KCP to control the output pulse and simultaneously detecting the output value IVi of the Hall sensor HR1If IVi1Greater than the adaptively learned pulse extraction value CT [ i][0]If the ratio is set, the CT loop is considered to be intact without disconnection, otherwise, the CT disconnection is judged, and the CT disconnection alarm is sent out.
Further, the polarity polling logic in step S5) includes: firstly, the fundamental current IVi of the CT is judged0If the current is greater than the CT no-current threshold, directly quitting the polarity detection logic, otherwise, judging whether the CT detects a broken line, and if so, directly quitting the polarity detection logic; otherwise, polarity detection is carried out, the same-different-symbol widths of the control output pulse IVout and the extraction input pulse Ivi are compared, if the same-symbol width TD1 is greater than the different-symbol width TD2 and TD1 is greater than the set proportion of the output period Tout of the control output pulse IVout, the CT polarity is considered to be correctly switched in, and otherwise, the polarity is judged to be reversely switched in.
Further, the adaptive learning includes: under the condition of giving an initial value, firstly changing Kf frequency points, increasing from a minimum value Kfmin by a step length df, changing Km from Kmmin to Kmmax by a step length dm at each frequency point, measuring to obtain a pulse back measurement maximum value Ivs in change, recording the maximum value Ivs, an output control frequency point kfi and an output control amplitude value kmi at the moment, storing the maximum value, the output control frequency point and the output control amplitude value into an IVi array, and sequencing all the maximum values Ivs from large to small after all frequency points are scanned; reading from large to small in the sequence, outputting a control pulse, detecting whether the fundamental current in the extraction pulse is larger than a CT no-current threshold value, if so, discarding the parameter and continuing to search next time until the optimal control parameter is obtained, and storing the optimal control parameter for controlling pulse output during disconnection polling and polarity polling.
Compared with the prior art, the wire breakage and polarity inspection system of the feedthrough current transformer and the control method thereof have the beneficial effects that: and detecting whether the straight-through transformer is broken or not and whether the polarity (same name end) is abnormal or not by a controllable narrow pulse injection mode. In particular, the method comprises the following steps of,
1) the online open-circuit and polarity inspection is carried out on the plurality of straight-through CTs in an inspection mode, so that the fault or abnormality of the primary current carrier of the CT can not be detected normally without manual detection;
2) the pulse output mode is adopted, the output time is short, the anti-interference energy is strong, and meanwhile, the output interference is reduced to the minimum, so that the interference on other equipment is avoided;
3) the problems of wire breakage, polarity and the like of a plurality of straight-through CTs can be inspected on line, and the working efficiency is greatly improved; the cost is reduced;
4) due to online inspection, problems can be found in time, an alarm is given, and the overhaul and the accident potential treatment are convenient;
5) the adaptive learning induction parameters are adopted for different CTs, the adaptive capacity of the system to different CTs and different wiring is improved on the premise of not influencing the normal monitoring of the CTs, and the detection accuracy and the reliability of detection results are guaranteed.
[ description of the drawings ]
Fig. 1-3 are schematic structural diagrams of disconnection and polarity detection of a current transformer in the prior art;
FIG. 4 is a schematic structural diagram of a frame in an embodiment of the present invention;
FIG. 5 is a schematic diagram of a connection structure of the inspection system and the feedthrough current transformer in the embodiment of the present invention;
FIG. 6 is a logical block diagram of a main program according to an embodiment of the present invention;
FIG. 7 is a logic block diagram of CT disconnection polling in an embodiment of the present invention;
FIG. 8 is a logic block diagram of CT polarity polling in an embodiment of the present invention;
FIG. 9 is a logic diagram of sensing parameter adaptation in accordance with an embodiment of the present invention;
FIG. 10 is a schematic diagram of a structure for determining the same or different polarity of CT symbols according to an embodiment of the present invention;
FIG. 11 is a three-dimensional view of the CT pulse sensing parameters in an embodiment of the present invention.
[ detailed description ] embodiments
Example (b):
referring to fig. 4-5, the present embodiment is a system for inspecting the disconnection and polarity of a feedthrough current transformer, which includes a multi-path pulse control and generation module a; a pulse recovery and measurement module B; a switching, pulse control and acquisition module C; and a core control, power supply and man-machine interaction and communication module D.
The multi-channel pulse control and generation module A is formed from controllable pulse generation circuit KCP [1,2, … …,9] and multi-channel switch selection circuits SWA and SWB. The control signals for KCP [1,2, … …,9] are Kf [1,2, … …,9] and Km [1,2, … …,9], respectively, where Kf [1,2, … …,9] is the frequency of the control pulse output and Km [1,2, … …,9] is the amplitude of the control pulse output. The action gating function of the multiple-way switch selection circuits SWA and SWB enables only one controllable pulse to be output at the same time. The multi-path pulse control and generation module A has the main functions of outputting pulses with controllable frequency and amplitude, the pulses are led out of two output terminals through a controllable pulse generation circuit KCP, the two output terminals penetrate through a lead from the primary side of the cross-core transformer CT, and the change of the pulses can be induced to the secondary side of the cross-core transformer CT.
The pulse recovery and measurement module B is composed of current Hall sensors HR [1,2, … …,9] and a multi-path switching selection circuit SWC, wherein the input of the Hall sensors HR is from the secondary output of the feed-through CT to measure the induction pulse generated by the multi-path pulse control and generation module A, and the multi-path switching selection circuit SWC is responsible for gating one Hall output in the HR [1,2, … …,9] to enter an analog measurement loop of the system and to be converted into a digital signal for processing through ADC digital-to-analog conversion.
And the switching, pulse control and acquisition module C consists of four circuit parts, namely a switching control circuit SMMD, a frequency control circuit FCMD, an amplitude control circuit VCMD and a data acquisition and conversion circuit ADIMD. The switching control circuit SMMD is responsible for pulse output selection control, namely selecting which KCP is output; the frequency control circuit FCMD and the amplitude control circuit VCMD are responsible for signal processing and shaping functions of output frequency and amplitude, and the data acquisition and conversion circuit ADIMD internally comprises a low-pass filter, an anti-interference circuit and an ADC acquisition circuit and is responsible for signal processing and acquisition of a recovery pulse.
The core control, power supply and man-machine interaction and communication module D mainly comprises a power supply POW of the system, a microprocessor and an external circuit MCU-MD, a touch screen and communication thereof in the man-machine interaction system, an Ethernet ETH communication interface communicated with an external power monitoring system and a driving circuit part thereof.
The working principle of the system of the embodiment is shown in fig. 5, and the working principle wiring of the system inspection is indicated in fig. 5. The cross-core mutual inductor CT1-CT9 is an object to be inspected, the system is mainly used for inspecting whether a secondary disconnection or polarity (same name end) of the mutual inductor is reversely connected in the cross-core mutual inductor CT1-CT9, and if the secondary disconnection or polarity (same name end) of the mutual inductor is reversely connected, alarm information can be prompted in a man-machine interaction system or communication, so that maintenance personnel can timely process the alarm information.
The wiring principle of the system is as follows: the pulse output terminals G1A and G1B are led through the primary aperture of the feedthrough transformer CT1, the incoming direction is the same as the current-regulated direction of the primary current carrier L1, as shown in fig. 5, the lead of the secondary output terminal P1 of the feedthrough transformer CT is led to the current hall sensor HR1 in the forward direction, and the outgoing line is connected to the secondary output terminal P2 after being connected to the load X1. When the system inspects the CT1, the two ends of G1A and G1B can generate a pulse with variable frequency and variable amplitude, the pulse can induce the secondary output ends P1 and P2 through the magnetic field of the feedthrough mutual inductor, and the pulse current at the two ends of P1 and P2 is measured through the current Hall sensor HR1, so that whether the CT1 is disconnected or connected with reverse polarity can be judged.
The present embodiment further provides a method for controlling disconnection and polarity inspection system of a feedthrough current transformer, the main program logic of which is shown in fig. 6, and the method includes:
s1) the main routine is started;
s2) initializing parameters and a system;
s3) reading the number N of patrol CTs, and setting a patrol serial number i to 0;
s4) executing the open circuit inspection logic of the CTi;
s5) executing polarity patrol logic for the CTi;
s6) making i equal to i +1, determining whether i is greater than N, if so, returning to step S3), and if not, returning to step S4);
in the main program logic, the loop polling is performed for N CTs, which corresponds to the system of this embodiment as N9. The inspection content mainly comprises the disconnection inspection and polarity inspection of the CT, and if the CT is disconnected or the polarity is abnormal, an alarm is given in the communication between the man-machine interaction system and the power monitoring system, so that operation and maintenance personnel can timely deal with the abnormal problem.
The open circuit inspection logic of step S4), as shown in FIG. 7, the logic first determines the fundamental current IVi of CT0If the current is larger than the CT no-current threshold, judging that current exists in the CT at the moment, and directly quitting the disconnection judging logic without disconnection; if the fundamental current IVi0And if the current is smaller than the CT no-current threshold, performing disconnection detection. If the CT does not have the pulse output parameters subjected to the adaptive learning, the detection is carried out after the adaptive learning is carried out. Software parameter CT [ i ] according to adaptive learning][1]Controlling KCP output amplitude, parameter CT [ i ]][2]Controlling KCP output frequency to control output pulse, and detecting output value IVi of Hall HR after passing through band-pass filter1If IVi1Greater than the previously adaptively learned pulse extraction value CT [ i][0]Preferably, the set ratio of (a) is CT [ i ]][0]The proportion of 50 percent and 50 percent of the CT circuit belongs to empirical values and is a reliable value, the logic considers that the CT circuit is intact and has no broken line, otherwise, the CT circuit is broken, and a CT broken line alarm is sent out. Parameter CT [ i ]][0]、CT[i][1]And CT [ i][2]And the pulse control parameters are obtained after the CTi is subjected to self-adaptive learning logic learning. The method specifically comprises the following steps:
s41) calculating the fundamental wave current value IVi of the CTi by using an FFT algorithm0；
S42) determining the fundamental wave current value IVi0Whether the current-free threshold value of the CTi is larger than the current-free threshold value of the CTi, if so, finishing the inspection, otherwise, executing the step S43);
s43) judging whether the CTi has adaptively learned the pulse output parameters, if not, executing CTi induction parameter adaptive learning logic, and then executing the next step; if the learning is finished, directly executing the next step;
s44) reading CT [ i ] [1] and CT [ i ] [2] to control output pulse;
s45) measurement IVi of the pulse measured by the band-pass filter1；
S46) judgment of IVi1Whether the value is larger than the pulse extraction value CT [ i ] which is self-adaptively learned][0]And if the percentage of the CTi is greater than 50%, finishing the inspection, otherwise, judging that the CTi is disconnected, outputting an alarm signal, and finishing the inspection.
The polarity polling logic in the step S5), as shown in fig. 8, the logic first determines the fundamental current IVi of the CT0If the current is larger than the CT no-current threshold, judging that the current exists in the CT, determining that the primary current carrier of the CT has unbalanced current or fault current, not performing polarity detection, and directly exiting polarity detection logic; if the CT detects the disconnection, the polarity detection cannot be carried out, and the polarity detection logic is directly quitted. Polarity detection mainly compares the same or different sign widths of the control output pulse IVout and the recovered input pulse IVi, as shown in fig. 9; if the different-symbol width TD2 is greater than the same-symbol width TD1, and the different-symbol width TD2 is greater than the set ratio of the output period Tout of the control output pulse IVout, preferably 50% of Tout, which is an empirical value and is also a more reliable value of 50%, then the polarity (same-name end) of the CT at this time is considered to be reversed, otherwise, the polarity is correctly switched in, and the polling is completed. The method specifically comprises the following steps:
s51) calculating the fundamental wave current value IVi of the CTi by using an FFT algorithm0；
S52) determining the fundamental wave current value IVi0Whether the current-free threshold of the CTi is larger than the current-free threshold of the CTi or not, if so, finishing the inspection, otherwise, executing the step S53);
s53) judging whether the CTi is broken, if so, finishing the inspection, otherwise, executing the next step;
s54) reading parameters CT [ i ] [1] and CT [ i ] [2] in the CTi sensing parameter self-adaptive learning logic to control output pulses;
s55) obtaining the same symbol width TD1 and different symbol width TD2 of the output pulse IVout and the extraction pulse IVi according to the extracted sampling data, and calculating to obtain the output pulse width Tout which is 1/CT [ i ] [2 ];
s56) judging whether TD2> TD1 and TD2>0.5Tout are true, if true, judging that the polarity of the CTi of the feedthrough transformer is reversed, and finishing the routing inspection, otherwise, judging that the polarity of the CTi of the feedthrough transformer is correct and finishing the routing inspection.
The sensing parameter adaptive learning logic in step S43 is shown in fig. 10-11. After the pulse of the inspection system is output to the primary side due to different types of straight-through CT parameters (such as transformation ratio difference and distributed capacitance inductance difference), installation position difference, length of a secondary lead wire and the like, the pulse induced by the secondary side of the inspection system is greatly different under the influence of different types of CTs, different installation positions, length of the secondary lead wire and the like, and the pulse is not output under the extreme condition. In order to avoid the situation, the sensing parameter adaptive learning logic can automatically change the frequency of pulse output and the amplitude of output to search for the most suitable control output parameter, and the maximum pulse sensing input Iv is obtained under the condition that the fundamental current output of the CT is not influenced. For the controllable quantities in the control system of the present embodiment: the relationship between the frequency control point Kf, the amplitude control point Km, and the maximum pulse induction input Iv (i.e., the input value of the hall sensor HR) is as shown in fig. 11. The self-adaptive learning process mainly comprises the steps of searching for the best sensitive point, changing Kf frequency points under the condition of giving an initial value, increasing the Kf frequency points from the minimum value Kfmin by a step length df, changing Km at each frequency point from Kmmin to Kmmax by a step length dm, measuring to obtain a pulse back-measurement maximum value Ivs in change, recording the maximum value Ivs at the moment, outputting a control frequency point kfi and an output control amplitude value kmi, storing the control frequency point and the output control amplitude value into an IVi array, and sequencing all maximum values Ivs from large to small after all frequency points are scanned. Reading from large to small in the sequence, outputting control, detecting whether the fundamental current in the extraction pulse is larger than a CT no-current threshold, and if so, abandoning the parameter and continuing to search next time. The purpose of this logic is to perform output pulse detection without affecting the other load devices X [1,2, … …,9] of the cross-core CT that monitor the CT current (other load devices monitor primarily the CT fundamental current, see fig. 2). After the optimal control parameters are obtained, the optimal control parameters are stored for controlling pulse output during the wire breakage routing inspection and the polarity routing inspection. The method specifically comprises the following steps:
s431) initializing parameters, including setting i to 0, setting Kfmin to 1Khz, setting Kfmax to 10Khz, setting frequency scanning step df to 5hz, setting pulse amplitude minimum Kmmin to 5V, setting pulse amplitude maximum Kmmax to 30V, and setting pulse amplitude step dm to 1V;
s432) setting output frequency point Kfi ═ Kfmin + i × df, i ═ 0,1, … …, p, p ═ Kfmax-Kfmin)/df-1; then changing amplitude output Kmj from Kmmin to Kmmax according to the step length dm, wherein j is 0,1, … …, and q is (Kmmax-Kmmin)/dm-1; outputting Kmj corresponding to a pulse extraction measurement data Ivj every amplitude, filtering low-frequency components by using a low-pass filter to obtain a corresponding value Ivj, finally searching a maximum value Ivs of Ivj in 0-q, namely Ivs ═ max (Iv0, Iv1, … … and Ivq), and storing the maximum value Ivs into an array IVi (IV [ i ] [0], IV [ i ] [1] and IV [ i ] [2]), wherein
IV [ i ] [0] ═ Ivs (Kfi bins, maximum amplitude values);
IV [ i ] [1] ═ Kmj (Kfi frequency points, output amplitude);
IV [ i ] [2] ═ Kfi (Kfi frequency points);
s433) determining Kfi < Kfmax, if yes, making i equal to i +1, and returning to step S432), if not, executing the next step;
s434) recording the arrays IVi, i ═ 0,1, … …, p of all frequency points in the variable step size df from Kfmin to Kfmax, obtaining an array set IVP, sorting the array set IVP in the order of Ivs from large to small, and storing the array set IVP in the arrays CT _ Rem [ X ] [3] (CT _ Rem [ X ] [0], CT _ Rem [ X ] [1], CT _ Rem [ X ] [2]), wherein CT _ Rem [ X ] [0] ═ Ivx, X ═ 0,1, … …, p, and Ivx gradually decreases as the value of X increases; CT _ Rem [ x ] [1] ═ Kmx; CT _ Rem [ x ] [2] ═ Kfx; and setting the output point serial number i to 0, i < x, x to 0,1, … …, p;
s435) reading amplitude control Kmx and frequency point control Kfx according to the signal i, and outputting control pulses; then, the fundamental current value Ivx in the pulse recovery Ivx is calculated0；
S436) determination Ivx0If the value is greater than the CTx no-flow threshold, if so, the sequence number i is set to i +1, and the process returns to step S435), and if not, the i output point information is recorded to the CTi (CT [ i |) (step S435)][0],CT[i][1],CT[i][2]) The characteristic parameter is stored in an array, in which CT [ i][0]Ivx (pulse extraction amplitude); CT [ i ]][1]Kmx (pulse control amplitude); CT [ i ]][2]Kfx (pulse control frequency points); and (5) finishing learning.
The system for inspecting the disconnection and polarity of the feedthrough current transformer and the control method thereof detect whether the feedthrough current transformer is disconnected or not and whether the polarity (dotted terminal) is abnormal or not through a controllable narrow pulse injection mode. In particular, the method comprises the following steps of,
1) the online open-circuit and polarity inspection is carried out on the plurality of straight-through CTs in an inspection mode, so that the fault or abnormality of the primary current carrier of the CT can not be detected normally without manual detection;
2) the pulse output mode is adopted, the output time is short, the anti-interference energy is strong, and meanwhile, the output interference is reduced to the minimum, so that the interference on other equipment is avoided;
3) the problems of wire breakage, polarity and the like of a plurality of straight-through CTs can be inspected on line, and the working efficiency is greatly improved; the cost is reduced;
4) due to online inspection, problems can be found in time, an alarm is given, and the overhaul and the accident potential treatment are convenient;
5) the adaptive learning induction parameters are adopted for different CTs, the adaptive capacity of the system to different CTs and different wiring is improved on the premise of not influencing the normal monitoring of the CTs, and the detection accuracy and the reliability of detection results are guaranteed.
What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.
Claims (10)
1. A cross-core current transformer disconnection and polarity inspection system and a control method thereof are characterized in that: which comprises
The pulse of the plurality of controllable pulse generating circuits KCP is output to the primary side of the straight-through mutual inductor CT;
the Hall sensors HR are responsible for pulse recovery and measurement, the number of the Hall sensors HR is the same as that of the controllable pulse generating circuits KCP, and secondary output terminals of the cross-core mutual inductor CT penetrate into the Hall sensors HR in the forward direction;
the multi-channel switch selection circuits SWA, SWB and SWC are used for controlling the frequency of pulses output by all the controllable pulse generation circuits KCP, controlling the amplitude of the pulses output by all the controllable pulse generation circuits KCP by the SWB and gating the output of a corresponding Hall sensor HR by the SWC;
the switching control circuit SWMD controls and selects one of the controllable pulse generating circuits KCP to output pulses;
the frequency control circuit FCMD and the amplitude control circuit VCMD respectively control the frequency and the amplitude of the output pulse and shape the output pulse;
the data acquisition and conversion circuit ADIMD is connected with the multi-path switch selection circuit SWC and is responsible for signal processing and acquisition of the recovery pulse; and
and the core control module is electrically connected with the switching control circuit SWMD, the frequency control circuit FCMD, the amplitude control circuit VCMD and the data acquisition and conversion circuit ADIMD.
2. The feedthrough current transformer disconnection and polarity inspection system of claim 1, wherein: the data acquisition and conversion circuit ADIMD internally comprises a low-pass filter, an anti-interference circuit and an ADC acquisition circuit.
3. The feedthrough current transformer disconnection and polarity inspection system of claim 1, wherein: the system also comprises a power supply for supplying power to the core control module and a man-machine interaction system communicated with the core control module.
4. The feedthrough current transformer disconnection and polarity inspection system of claim 1, wherein: the core control module is in communication with an external power monitoring system.
5. The feedthrough current transformer disconnection and polarity inspection system of claim 1, wherein: and a pulse output terminal of the controllable pulse generation circuit KCP penetrates through the primary side aperture of the feedthrough transformer through a lead, and the transmission direction of the pulse output terminal is the same as the current specified direction of a primary current carrier.
6. The feedthrough current transformer disconnection and polarity inspection system of claim 1, wherein: the lead of the secondary output terminal P1 of the feedthrough transformer CT is inserted into the current Hall sensor in the forward direction, and the outgoing line is connected to the load and then connected to the secondary output terminal P2 of the feedthrough transformer CT.
7. The control method of the wire breakage and polarity inspection system of the feedthrough current transformer according to claim 1, is characterized in that: which comprises
S1) the main routine starts;
s2) initializing parameters and a system;
s3) reading the number N of patrol CTs, and setting a patrol serial number i to 0;
s4) executing the open circuit inspection logic of the CTi;
s5) executing polarity patrol logic for the CTi;
s6) sets i to i +1, determines whether i is larger than N, and if so, returns to step S3), and if not, returns to step S4).
8. The control method of the wire breakage and polarity inspection system of the feedthrough current transformer of claim 7, wherein: the open circuit inspection logic in the step S4) comprises the following steps: firstly, the fundamental current IVi of the cross-core mutual inductor CT is judged0If the current is larger than the CT no-flow threshold value, quitting the disconnection polling logic if the current is larger than the CT no-flow threshold value, otherwise, performing disconnection detection; making CT carry out self-adaptive learning logic to obtain pulse output parameter CT [ i][0]、CT[i][1]And CT [ i][2](ii) a According to the parameter CT [ i][1]Controlling the output amplitude of the controllable pulse generating circuit KCP according to the parameter CT [ i][2]Controlling the output frequency of the controllable pulse generating circuit KCP to control the output pulse and simultaneously detecting the output value IVi of the Hall sensor HR1If IVi1Greater than the adaptively learned pulse extraction value CT [ i][0]If the ratio is set, the CT loop is considered to be intact without disconnection, otherwise, the CT disconnection is judged, and the CT disconnection alarm is sent out.
9. The feedthrough current of claim 7The control method of the mutual inductor disconnection and polarity inspection system is characterized in that: the polarity polling logic in step S5), which includes: firstly, the fundamental current IVi of the CT is judged0If the current is greater than the CT no-current threshold, directly quitting the polarity detection logic, otherwise, judging whether the CT detects disconnection, and if so, directly quitting the polarity detection logic; otherwise, polarity detection is carried out, the same-different-symbol widths of the control output pulse IVout and the extraction input pulse Ivi are compared, if the same-symbol width TD1 is greater than the different-symbol width TD2 and TD1 is greater than the set proportion of the output period Tout of the control output pulse IVout, the CT polarity is considered to be correctly switched in, and otherwise, the polarity is judged to be reversely switched in.
10. The control method of the wire breakage and polarity inspection system of the feedthrough current transformer of claim 8, wherein: the adaptive learning includes: under the condition of giving an initial value, firstly changing Kf frequency points, increasing from a minimum value Kfmin by a step length df, changing Km from Kmmin to Kmmax by a step length dm at each frequency point, measuring to obtain a pulse back measurement maximum value Ivs in change, recording the maximum value Ivs, an output control frequency point kfi and an output control amplitude value kmi at the moment, storing the maximum value, the output control frequency point and the output control amplitude value into an IVi array, and sequencing all the maximum values Ivs from large to small after all frequency points are scanned; reading from large to small in the sequence, outputting a control pulse, detecting whether the fundamental current in the extraction pulse is larger than a CT no-current threshold value, if so, discarding the parameter and continuing to search next time until the optimal control parameter is obtained, and storing the optimal control parameter for controlling pulse output during disconnection polling and polarity polling.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117075027A (en) * | 2023-10-16 | 2023-11-17 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117075027A (en) * | 2023-10-16 | 2023-11-17 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
| CN117075027B (en) * | 2023-10-16 | 2024-01-26 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
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