Power transformation secondary control cable core on-line searching system and method
By designing a substation secondary control cable core online search system with simple structure and low cost, the current curve similarity comparison and identification of the core is solved, and the problems of inefficiency and safety risks of traditional core methods are achieved, and high efficiency is achieved. Accurate cable core identification.
Patent Information
- Application Number
- CN202411570619.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-02-14
AI Technical Summary
In the daily operation and maintenance of substations, traditional core-adjustment methods are inefficient, have safety risks, and the use cost of high-precision electronic equipment is high and complex to operate.
A substation secondary control cable core online search system is designed, including a charging circuit and a current detection device. The corresponding core is determined by comparing the current curve similarity. The system structure is simple and cost-effective, and is suitable for large-scale applications.
It realizes efficient and accurate cable core identification, reduces operational complexity and cost, is highly adaptable, and is suitable for substation cable core inspection in any occasion and environment.
Smart Images
Figure CN119438988A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of substation maintenance, and in particular to a system and method for online searching of substation secondary control cable cores. Background Art
[0002] In the daily operation and maintenance of substations, the correct identification and rapid identification of cable cores are crucial. Due to the large number of cable cores and the large number of cores in each cable, the traditional core alignment method is often inefficient and has certain safety risks.
[0003] The traditional core alignment method usually relies on a multimeter for continuity testing, which is not only cumbersome, but also has the risk of AC and DC circuit short circuit or grounding. Especially in the switch control circuit, incorrect cable-to-ground connection may cause the switch to malfunction. In addition, in the case of long cables, large interference or poor substation grounding network, the measured resistance to ground is large and discrete, increasing the risk of on-site misjudgment.
[0004] In order to overcome these shortcomings, an inductive secondary cable core alignment instrument was designed. This device consists of a signal generator and a core alignment device. The signal generator emits a high-frequency signal of a specific frequency, which is connected to the cable that needs to be aligned through a dedicated interface for the secondary cable, generating a surrounding signal field around the cable. The core alignment device uses high-sensitivity sensing to identify the target signal, thereby determining whether the two ends of the cable are the same cable core. However, this high-precision electronic device itself will bring additional costs, and in some cases, operators may still need some training to be proficient in using the device, especially for the secondary cable verification method of asymmetric phase induction current signals, which may require professional technical knowledge to operate correctly and is inconvenient to use. Summary of the invention
[0005] The purpose of the present invention is to provide a system and method for online searching of substation secondary control cable cores, which not only does not require high-precision electronic equipment and instruments, but is also convenient for operators to use, and also has excellent detection efficiency and accuracy.
[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: The invention discloses an online search system for the core of a substation secondary control cable, comprising a charging circuit and a first current detection device, wherein the charging circuit comprises a charging capacitor, a charging circuit switch contact and a second current detection device, wherein the input end of the charging circuit is connected to the input end of the core to be tested, the output end of the charging circuit is connected to the output end of the core to be tested, a device is connected between the input end and the output end of the core to be tested, the first current detection device is used to detect the current at the input end of the core to be tested, and the second current detection device is used to detect the input current of the charging circuit.
[0007] Furthermore, the online search system for the core of the substation secondary control cable also includes a starting circuit for starting the charging circuit. The starting circuit includes a time relay K1 and an intermediate relay ZJ. The normally closed contact and the normally open contact of the intermediate relay ZJ constitute the switch contact of the charging circuit. The normally closed contact of the intermediate relay ZJ is connected in parallel with the charging capacitor, and the normally open contact of the intermediate relay ZJ is connected in series with the charging capacitor.
[0008] Furthermore, the charging circuit also includes a fuse, a voltage-dividing resistor R1 and a discharge resistor R2. The voltage-dividing resistor R1, the normally open contact of the intermediate relay, the charging capacitor and the fuse are connected in series. The branch formed by the discharge resistor R2 and the normally closed contact of the intermediate relay is connected in parallel with the charging capacitor.
[0009] Furthermore, the first current detection device and the second current detection device are both ammeters.
[0010] The method for online searching of the core of a substation secondary control cable is implemented based on the above-mentioned online searching system for the core of a substation secondary control cable, and comprises the following steps: Collect the total current at the input end of the wire to be tested , Charging circuit input current ; The collected current data is preprocessed, and the unreasonable data is discarded to form a continuous curve, and the current data is calculated separately. , The slope of each point of the current curve , ; Will , The current curves are compared. When the two are similar, it is considered that the current The core that flows through is determined as the core that needs to be found.
[0011] Furthermore, unreasonable data include: when the current at a certain detection point changes suddenly or the rate of change between the previous and next points is zero, the current data measured at the detection point is discarded.
[0012] Furthermore, , The method for determining curve similarity is: Select the charging circuit input current of the mth detection point at a certain moment ; Read In The slope of the current curve ; exist Select the current curve Slopes of the same or closest value , and read the slope as Current output ; Calculate the current change between the two points and record it as , if satisfied , record the mth detection point as a valid point, where is a variable parameter, and its value is ; Traversal For each point on the current curve, the number of effective points is recorded as P, the number of ineffective points is recorded as Q, and the percentage of effective points is calculated. ,satisfy It is believed that , The current curves are similar, where is a similarity parameter and its value is 0.98.
[0013] Furthermore, the instantaneous action delayed return contact of the time relay K1 is taken as the starting condition of the intermediate relay ZJ. When starting to work, the K1 action contact is energized, the intermediate relay ZJ is energized, the normally open contact of the intermediate relay ZJ is closed, the normally closed contact of the intermediate relay ZJ is disconnected, the charging circuit is connected, and the charging capacitor starts to be charged; the K1 action contact returns, the intermediate relay ZJ loses power, the normally open contact of the intermediate relay ZJ is disconnected, the normally closed contact of the intermediate relay ZJ is closed, the charging circuit is disconnected, and the capacitor is discharged.
[0014] The advantages of the present invention are: the system has a small number of components, a simple structure, and power consumption is much lower than that of the existing secondary cable core alignment instrument, which can save energy in the case of long-term operation, is suitable for large-scale application, and has a low manufacturing cost and is easy to mass produce; It can be operated without special training for technicians, and has strong adaptability. With added protection function, it can be used for substation cable core detection in any occasion and environment. The correspondence of the wire cores can be determined by comparing the similarity of the current curves, with high accuracy, large fault tolerance, and more intelligent identification, which is much more accurate than manual detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a schematic diagram of the structure of an online search system for substation secondary control cable cores according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a charging circuit according to Embodiment 1 of the present invention; Figure 3 This is a flow chart of an online method for searching a substation secondary control cable core according to Embodiment 2 of the present invention; Figure 4 Schematic diagram of the current curve of Example 2 of the present invention. DETAILED DESCRIPTION
[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0017] Example 1 Please refer to Figure 1 The present embodiment discloses an online search system for a substation secondary control cable core, including a charging circuit, a starting circuit and a first ammeter, wherein the upper end of the first ammeter is connected to the live wire end of the cable core input, and the lower end is connected to the charging circuit input end.
[0018] The starting circuit includes a time relay K1 and an intermediate relay ZJ connected in series, which together form a circuit.
[0019] Please refer to Figure 2 The charging circuit includes a second ammeter, a charging capacitor, a normally closed contact ZJ43-44 of an intermediate relay ZJ, a normally open contact ZJ13-14 of an intermediate relay ZJ, two fuses FL, a voltage-dividing resistor R1 and a discharge resistor R2. The second ammeter, the first fuse FL, the normally open contact ZJ13-14 of the intermediate relay ZJ, the charging capacitor and the second fuse FL are connected in series in sequence. The other end of the second ammeter (i.e., the input end of the charging circuit) is connected to the lower end of the first ammeter, and the other end of the second fuse FL (i.e., the output end of the charging circuit) is connected to the output end of the line core to be tested. The branch formed by the discharge resistor R2 and the normally closed contact ZJ43-44 of the intermediate relay is connected in parallel with the charging capacitor. A device is connected between the input end and the output end of the line core to be tested.
[0020] Example 2 Based on the online search system for substation secondary control cable cores in Example 1, this embodiment proposes an online search method for substation secondary control cable cores, setting the first ammeter to measure the total current at the input end of the cable core. The second ammeter measures the current flowing through the charging circuit. , the DC load current of the device is The principle of this method is that when the circuit is operating normally, only the device , after the charging circuit is turned on, , current According to the circuit characteristics analysis, when the capacitor is not connected to work, the total current Only load current , which is a stable DC current; after the charging circuit is connected, the charging capacitor needs to be charged, forming a charging current. From maximum to zero, it decreases nonlinearly. The changing process is ① stable DC current ② gradually decreasing nonlinear current ③ stable DC current. Please refer to the current curve Figure 4 .
[0021] Please refer to the search process using the above principle Figure 3 When working starts, the time relay acts, and the instantaneous action delayed return contact of the relay is taken as the starting condition of the intermediate relay ZJ. The K1 action contact is energized, the intermediate relay ZJ is energized, the normally open contacts ZJ13-14 of the intermediate relay ZJ are closed, and the normally closed contacts ZJ43-44 of the intermediate relay ZJ are disconnected, connecting the charging circuit and starting to charge the charging capacitor; the K1 action contact returns, the intermediate relay ZJ loses power, the normally open contacts ZJ13-14 of the intermediate relay ZJ are disconnected, and the normally closed contacts ZJ43-44 of the intermediate relay ZJ are closed, disconnecting the charging circuit and discharging the capacitor.
[0022] The rate of change of current For judgment, if the current at a certain point on the total current curve changes suddenly or the rate of change between the previous and next points is zero, the point is discarded, and only the points where the current changes continuously are retained, and the time, current value, and slope triplet information of all retained points are recorded, that is, the total current calculation triplet For comparison purposes, the total current value measured minus the current value of the DC load is used to obtain the current value of the charging circuit. , recorded as the charging circuit triplet information.
[0023] Compare the processed total current calculation triplet information with the additional current triplet information, and select the current sampling value at a certain moment based on the charging circuit current information. And read the slope at that point , in the calculation of triples Select and Same or most recent current slope value , and read the current sampling value at this point at the same time , calculate the current change between the two points, recorded as , calculate the current change between the two points, recorded as , if satisfied , Value , record the mth detection point as a valid point, and record the number of all detection points that meet the requirements, recorded as , those that do not meet the requirements are recorded as , until all the data that can be read are calculated, and the percentage of the number that meets the requirements is calculated, recorded as , percentage satisfied This proves that the total current and charging current Similar, current The cable core is the one you want to find. The value is 0.98.
[0024] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. The online search system for substation secondary control cable cores is characterized by: It includes a charging circuit and a first current detection device, the charging circuit includes a charging capacitor, a charging circuit switch contact and a second current detection device, the input end of the charging circuit is connected to the input end of the core to be tested, the output end of the charging circuit is connected to the output end of the core to be tested, a device is connected between the input end and the output end of the core to be tested, the first current detection device is used to detect the current at the input end of the core to be tested, and the second current detection device is used to detect the input current of the charging circuit.
2. According to claim 1, the online search system for substation secondary control cable cores is characterized in that: It also includes a starting circuit for starting the charging circuit, the starting circuit includes a time relay K1 and an intermediate relay ZJ, the normally closed contact and the normally open contact of the intermediate relay ZJ constitute the charging circuit switch contact, the normally closed contact of the intermediate relay ZJ is connected in parallel with the charging capacitor, and the normally open contact of the intermediate relay ZJ is connected in series with the charging capacitor.
3. The online search system for substation secondary control cable cores according to claim 2 is characterized in that: The charging circuit also includes a fuse, a voltage-dividing resistor R1 and a discharge resistor R2. The voltage-dividing resistor R1, the normally open contact of the intermediate relay, the charging capacitor and the fuse are connected in series. The branch formed by the discharge resistor R2 and the normally closed contact of the intermediate relay is connected in parallel with the charging capacitor.
4. The online search system for substation secondary control cable cores according to claim 1 is characterized in that: The first current detection device and the second current detection device are both ammeters.
5. A method for online searching of the core of a secondary control cable of a substation, which is implemented based on the online searching system for the core of a secondary control cable of a substation according to any one of claims 1 to 4, and is characterized in that: Includes steps: Collect the total current at the input end of the wire to be tested , Charging circuit input current ; The collected current data is preprocessed, and the unreasonable data is discarded to form a continuous curve, and the current data is calculated separately. , The slope of each point of the current curve , ; Will , The current curves are compared. When the two are similar, it is considered that the current The core that flows through is determined as the core that needs to be found.
6. The method for online searching of the core of a substation secondary control cable according to claim 5 is characterized in that: The unreasonable data includes: when the current at a certain detection point has a sudden change or the change rate between the previous and next points is zero, the current data measured at the detection point is discarded.
7. The method for online searching of the core of a substation secondary control cable according to claim 5 is characterized in that: , The method for determining curve similarity is: Select the charging circuit input current of the mth detection point at a certain moment ; Read In The slope of the current curve ; exist Select the current curve Slopes of the same or closest value , and read the slope as Current output ; Calculate the current change between the two points and record it as , if satisfied , record the mth detection point as a valid point, where is a variable parameter, and its value is ; Traversal For each point on the current curve, the number of effective points is recorded as P, the number of ineffective points is recorded as Q, and the percentage of effective points is calculated. ,satisfy It is believed that , The current curves are similar, where is a similarity parameter and its value is 0.
98.
8. The method for online searching of the core of a substation secondary control cable according to claim 5 is characterized in that: The instantaneous action delayed return contact of time relay K1 is taken as the starting condition of intermediate relay ZJ. When starting to work, K1 action contact is energized, intermediate relay ZJ is energized, the normally open contact of intermediate relay ZJ is closed, the normally closed contact of intermediate relay ZJ is disconnected, the charging circuit is connected, and the charging capacitor starts to be charged; K1 action contact returns, intermediate relay ZJ loses power, the normally open contact of intermediate relay ZJ is disconnected, the normally closed contact of intermediate relay ZJ is closed, the charging circuit is disconnected, and the capacitor is discharged.