Current transformer with insulation detection function
By integrating sensor modules, signal conditioning circuits, and alarm circuits, the current transformer solves the problem of difficulty in monitoring insulation performance degradation in existing technologies, realizes real-time insulation status monitoring of the current transformer, and ensures the safe and stable operation of the power system.
Patent Information
- Application Number
- CN202520276467.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2035-02-20
AI Technical Summary
Existing current transformers lack effective insulation monitoring mechanisms, making it difficult to detect insulation performance degradation in a timely manner, leading to equipment damage and large-scale power outages.
Design a current transformer with insulation detection function, integrating a sensor module, signal conditioning circuit, comparator circuit and alarm circuit, to monitor the insulation performance of the current transformer in real time and issue an alarm signal in time when the performance deteriorates.
It enables real-time insulation status monitoring of current transformers, avoiding equipment damage and safety accidents caused by insulation faults, and ensuring the stable operation of the power system.
Smart Images
Figure CN223955671U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of electric power equipment, in particular to a current transformer with insulation detection function. BACKGROUND
[0002] As the core equipment of the power system, the current transformer is responsible for converting large current into small current in proportion, and is widely used in power generation, power transmission, power distribution and industrial automation fields. For example, monitoring the generator output current in the power plant, measuring the line current in the power grid transmission line, controlling the motor operating current in industrial production, etc. It is very important to ensure the stable operation of the power system. In the long-term complex environment, the traditional current transformer is prone to insulation aging, dampness, partial discharge and other problems. The decline of insulation performance may cause breakdown, short circuit fault, resulting in equipment damage and large area power failure. And the traditional detection method depends on periodic offline preventive test, which has long cycle and cannot reflect the insulation condition in real time, so it is difficult to find fault hidden danger in advance. Part of the external insulation detection system has complex structure, needs a large number of sensors and complex wiring, high cost, difficult installation, and signal transmission is easy to be disturbed by electromagnetic interference, the detection result accuracy is poor, at the same time, the existing detection technology is difficult to adapt to the complex operation condition of power system, and it is difficult to accurately detect the early change of insulation performance under special working condition, which delays the fault warning opportunity. Therefore, it is necessary to design a current transformer with insulation detection function to solve the above problems. SUMMARY
[0003] The utility model wants to solve the technical problem that provides a kind of current transformer with insulation detection function, to solve the problem that current transformer lacks effective insulation monitoring mechanism and is difficult to find insulation performance decline in time.
[0004] To solve the above technical problems, the technical scheme adopted by the utility model is:
[0005] A kind of current transformer with insulation detection function, including current transformer body and insulation detection circuit;Current transformer body includes iron core assembly and winding assembly;And, the iron core assembly is made of single ring iron core;The winding assembly includes primary winding and secondary winding, which are all wound on the iron core assembly;And, the number of turns of the primary winding and the secondary winding is designed according to the ratio requirement of current transformer, and the winding adopts multi-layer tight winding process.
[0006] Among them, the insulation detection circuit includes sensor module, signal conditioning circuit, comparator circuit and alarm circuit. Among them, the sensor module is provided with analog resistance R1 related to insulation state, one end of R1 is connected to the secondary winding of the current transformer, for obtaining the electric signal related to the insulation performance of the transformer. When the insulation performance of the transformer changes, the resistance of R1 will change accordingly.
[0007] The signal conditioning circuit is composed of an operational amplifier U1, a capacitor C1 and a resistor R2; and the signal conditioning circuit is used to filter out high-frequency interference signals in the electrical signal and amplify the weak electrical signal input by R1 in the sensor module, so as to improve the signal quality; the operational amplifier U1 adopts a high-gain and low-noise type to meet the amplification requirement of the weak signal; the capacitor C1 selects a ceramic capacitor, and the capacitance value is selected according to the frequency of the high-frequency interference signal to be filtered out.
[0008] The comparator circuit includes a comparator U2, which compares the amplified signal output by the signal conditioning circuit with a reference voltage. The reference voltage is provided by a voltage dividing circuit composed of R3 and a power supply. When the insulation of the current transformer is normal, the detection signal is higher than the reference voltage; when the insulation performance decreases and causes the resistance value of R1 to change, the detection signal is lower than the reference voltage, and at this time the comparator U2 outputs a low-level signal.
[0009] The alarm circuit is connected with the comparator U2, and when the comparator U2 outputs a low level, the alarm circuit is triggered to work, and an alarm signal is sent out through driving a light-emitting diode or a buzzer, so as to remind the operator to take timely measures.
[0010] Further, the secondary winding of the current transformer connected with R1 in the sensor module is the winding layer closest to the outermost layer of the iron core, so that the application can more sensitively capture the change of the insulation performance.
[0011] Further, the alarm circuit includes a driving circuit, which provides a suitable driving current for the light-emitting diode or the buzzer according to the low-level signal output by the comparator U2, so as to ensure the normal working of the light-emitting diode or the buzzer to send out the alarm signal.
[0012] Further, the insulation detection circuit and the current transformer body are connected by a shielded wire, which effectively reduces the influence of external electromagnetic interference on the insulation detection signal.
[0013] Further, the iron core material is selected from soft magnetic alloys with high magnetic permeability, such as permalloy or iron-silicon-aluminum magnetic powder core, to meet different magnetic performance requirements.
[0014] Further, during the winding process of the winding assembly, an insulating material is used for insulation between layers to enhance the insulation performance of the winding.
[0015] Further, the current transformer can monitor the insulation performance of the current transformer in real time through the integrated insulation detection circuit, and timely send out an alarm signal when the insulation performance decreases, effectively avoiding equipment damage and safety accidents caused by insulation failure. At the same time, the optimization design of the iron core assembly and the winding assembly ensures the high performance and stability of the current transformer under different current conditions.
[0016] Compared with the prior art, the current transformer with the insulation detection function has the advantages that:
[0017] 1. The permalloy core with high magnetic permeability and high saturation magnetic induction value is adopted to ensure high performance of the current transformer under different current conditions.
[0018] 2. The winding adopts the multi-layer dense winding process and insulation material isolation to improve the electromagnetic coupling efficiency and insulation performance.
[0019] 3. The integrated insulation detection circuit is used to monitor the insulation state of the current transformer in real time, and ensure safe operation. BRIEF DESCRIPTION OF DRAWINGS
[0020] Fig. 1 is a combined schematic view of the current transformer and the insulation detection circuit;
[0021] Fig. 2 is an insulation detection flow chart;
[0022] Fig. 3 is a schematic view of an insulation detection module;
[0023] In the figure: resistor R15, capacitor C16, resistor R27, operational amplifier U18, resistor R39, comparator U210, light-emitting diode 12, buzzer 14, secondary winding 15, single core 16, primary winding 17, sensor module 18, signal conditioning circuit 19, comparator circuit 20, alarm circuit 21. DETAILED DESCRIPTION
[0024] Example 1
[0025] As shown in Figs. 1-3 , a current transformer with insulation detection function includes a current transformer body and an insulation detection circuit. The current transformer body includes a core assembly and a winding assembly. The core assembly is composed of a single ring core. The winding assembly includes a primary winding 17 and a secondary winding 15, both of which are wound on the core assembly. The turns ratio of the primary winding 17 and the secondary winding 15 is designed according to the ratio requirement of the current transformer, and the winding adopts a multi-layer dense winding process.
[0026] The insulation detection circuit includes a sensor module 18, a signal conditioning circuit 19, a comparator circuit 20 and an alarm circuit 21. The sensor module 18 is provided with an analog resistor R15 related to the insulation state. One end of the resistor R1 is connected to the secondary winding 15 of the current transformer to obtain an electrical signal related to the insulation performance of the current transformer. When the insulation performance of the current transformer changes, the resistance of R1 will change accordingly.
[0027] The signal conditioning circuit 19 is composed of an operational amplifier U18, a capacitor C16 and a resistor R27; and the signal conditioning circuit 19 is used for filtering high-frequency interference signals in the electrical signal and amplifying the weak electrical signal inputted by R1 in the sensor module 18, so as to improve the signal quality; the operational amplifier U18 adopts a high-gain and low-noise type to meet the amplification requirement of the weak signal; and the capacitor C16 selects a ceramic capacitor, and the capacitance value is selected according to the frequency of the high-frequency interference signal to be filtered.
[0028] The comparator circuit 20 includes a comparator U210, which compares the amplified signal outputted by the signal conditioning circuit 19 with a reference voltage. The reference voltage is provided by a voltage dividing circuit composed of R3 and a power supply. When the insulation of the current transformer is normal, the detection signal is higher than the reference voltage; when the insulation performance decreases to cause the resistance value of R1 to change, the detection signal is lower than the reference voltage, and at this time, the comparator U210 outputs a low-level signal.
[0029] The alarm circuit is connected with the comparator U210, and when the comparator U210 outputs a low level, the alarm circuit is triggered to work, and an alarm signal is sent out through the driving of the light-emitting diode 12 or the buzzer 14, so as to remind the operator to take measures in time.
[0030] Further, the current transformer secondary winding 15 connected with R1 in the sensor module 18 is the winding layer closest to the outermost layer of the iron core, so that the application can more sensitively capture the change of the insulation performance.
[0031] Further, the alarm circuit includes a driving circuit, which provides a suitable driving current for the light-emitting diode 12 or the buzzer 14 according to the low-level signal outputted by the comparator U210, so as to ensure the normal work of the light-emitting diode 12 or the buzzer 14 to send out the alarm signal.
[0032] Further, the insulation detection circuit and the current transformer body are connected by a shielding wire, which effectively reduces the influence of external electromagnetic interference on the insulation detection signal.
[0033] Further, the iron core material selects a soft magnetic alloy with high magnetic permeability, such as a permalloy or a ferrosilicon aluminum magnetic powder core, to meet different magnetic performance requirements.
[0034] Further, during the winding process of the winding assembly, an insulating material is used for insulation between layers to enhance the insulation performance of the winding.
[0035] Further, the current transformer can monitor the insulation performance of the current transformer in real time through the integrated insulation detection circuit, timely issue an alarm signal when the insulation performance decreases, and effectively avoid equipment damage and safety accidents caused by insulation failure. At the same time, the optimized design of the core assembly and the winding assembly ensures the high performance and stability of the current transformer under different current conditions.
[0036] Embodiment two:
[0037] The embodiment provides a basic type of current transformer with insulation detection function, and the structure is as shown in Fig. 1 The current transformer mainly includes a current transformer body and an insulation detection circuit.
[0038] The current transformer body includes a core assembly and a winding assembly; the core assembly is composed of a single high-magnetic-permeability high-saturation-magnetic-inductance permalloy core, and the core shape is annular to reduce magnetic leakage and meet the performance requirements of the current transformer under different current conditions; the winding assembly includes a primary winding 17 and a secondary winding 15, both of which are wound on the core. The turns ratio of the primary winding 17 and the secondary winding 15 is designed according to the transformation ratio requirement of the current transformer, for example, 100:1.
[0039] Specifically, the winding adopts a multi-layer dense winding process, and the interlayer is isolated by using an insulating material such as polyimide film, so as to improve the electromagnetic coupling efficiency of the winding and enhance the insulation performance of the winding.
[0040] In the embodiment, the insulation detection circuit mainly includes a sensor module 18, a signal conditioning circuit 19, a comparator circuit 20 and an alarm circuit 21, which are used to monitor the insulation performance of the current transformer in real time.
[0041] The sensor module 18 is provided with an analog resistance R15 related to the insulation state, one end of the resistance R15 is connected to the outermost winding layer of the secondary winding 15 of the current transformer, and the resistance R15 is used to obtain an electrical signal related to the insulation performance of the current transformer; when the insulation performance of the current transformer changes, the resistance value of the resistance R15 will change accordingly.
[0042] In the embodiment, the signal conditioning circuit 19 is composed of a high-gain low-noise operational amplifier U18 such as LM741 type, a ceramic capacitor C16 and a resistance R27; the capacitor C16 is used to filter out high-frequency interference signals in the electrical signal, and the resistance R27 cooperates with the operational amplifier U18 to amplify the weak electrical signal input by the resistance R15 in the sensor module 18, so as to improve the signal quality.
[0043] In this embodiment, the comparator circuit 20 includes a comparator U210, for example, model LM393, which compares the amplified signal output by the signal conditioning circuit 19 with a reference voltage. The reference voltage is provided by a voltage divider circuit composed of R3 and the power supply. When the transformer insulation is normal, the detection signal is higher than the reference voltage, and the comparator U210 outputs a high-level signal; when the insulation performance decreases and causes the resistance of R15 to change, the detection signal is lower than the reference voltage, and the comparator U210 outputs a low-level signal.
[0044] In this embodiment, the alarm circuit 21 is connected to the comparator U210, and when the comparator U210 outputs a low level, it triggers the alarm circuit 21 to work, emitting an alarm signal through the driving of the light-emitting diode 12 or the buzzer 14.
[0045] Example Three:
[0046] Optimized current transformer with insulation detection function:
[0047] This embodiment optimizes the insulation detection circuit based on Example 1 to improve the sensitivity and accuracy of insulation detection.
[0048] In this embodiment, the sensor module 18 uses a higher-precision resistor R15 to improve the sensitivity of insulation detection. At the same time, the connection method of the resistor R15 is optimized to reduce contact resistance and interference.
[0049] In addition, a feedback resistor R4 is added to the signal conditioning circuit 19, which together with the operational amplifier U18 forms an inverting amplifier circuit, further amplifying the signal and reducing noise interference. At the same time, the capacitance of the capacitor C16 is optimized to better filter out high-frequency interference signals.
[0050] In this embodiment, the comparator circuit 20 is adjusted: the reference voltage of the comparator U210 is adjusted by fine-tuning the resistance of R3 to change the reference voltage value to adapt to the insulation detection requirements in different working environments. And the threshold voltage of the comparator U210 is calibrated to ensure that the comparator can accurately compare the detection signal with the reference voltage.
[0051] In addition, the alarm signal duration control and silencing function are added to the alarm circuit 21 to avoid false positives or false negatives and improve user experience.
[0052] Example Four:
[0053] Variant type current transformer with insulation detection function:
[0054] This embodiment provides a variant type current transformer with insulation detection function, mainly different in core material and winding structure.
[0055] In this embodiment, the core material is changed: iron-silicon-aluminum magnetic powder core is used instead of permalloy as the core material to reduce cost while maintaining high permeability and saturation magnetic induction value. The core shape is still ring-shaped to meet the performance requirements of the current transformer.
[0056] Moreover, the winding structure is changed: the winding is precisely divided into several segments, and the length of each segment is accurately calculated according to the size of the current transformer, the expected current load, and the required electromagnetic performance. Moreover, high-performance insulation materials such as polyester film, polyimide film, or special ceramic insulation paper are used to separate each segment of the winding, ensuring electrical isolation between segments while maintaining good mechanical strength and heat resistance.
[0057] In addition, based on the target inductance value, operating frequency, and required accuracy, the optimal number of turns is determined through simulation analysis using electromagnetic simulation software such as ANSYS Maxwell, FEMM, etc. The winding is arranged in a multi-layer structure, and the number of turns in each layer is designed according to the principle of uniform electromagnetic field distribution to avoid local overheating and magnetic saturation. Thin insulation layers are used to separate the layers to control the interlayer capacitance and reduce high-frequency signal interference.
Claims
1. A current transformer with insulation detection function, characterized in that, The current transformer body comprises a core assembly and a winding assembly, the core assembly is composed of a single core (16), and the winding assembly comprises a primary winding (17) and a secondary winding (15), the primary winding (17) and the secondary winding (15) are both wound on the single core (16); the turn ratio of the primary winding (17) to the secondary winding (15) is designed according to the transformation ratio requirement of the current transformer, and the winding adopts a multi-layer dense winding process. The insulation detection circuit comprises a sensor module (18), a signal conditioning circuit (19), a comparator circuit (20) and an alarm circuit (21); the sensor module (18) is provided with an analog resistance R1 (5) related to an insulation state, one end of the resistance R1 (5) is connected to the secondary winding (15) of the current transformer for obtaining an electric signal related to the insulation performance of the current transformer, when the insulation performance of the current transformer changes, the resistance value of R1 (5) changes accordingly; the signal conditioning circuit (19) comprises an operational amplifier U1 (8), a capacitor C1 (6) and a resistance R2 (7), the capacitor C1 (6) is used for filtering high-frequency interference signals in the electric signal, the resistance R2 (7) cooperates with the operational amplifier U1 (8) to amplify and process the weak electric signal input by the resistance R1 (5) in the sensor module (18), and outputs the amplified signal to the comparator circuit (20); the comparator circuit (20) comprises a comparator U2 (10), the comparator U2 (10) compares the amplified signal output by the signal conditioning circuit (19) with a reference voltage; the alarm circuit (21) is connected with the comparator U2 (10).
2. The current transformer with insulation detection function according to claim 1, characterized in that, The secondary winding (15) of the current transformer connected with the resistance R1 (5) in the sensor module (18) is the winding layer closest to the outermost layer of the core.
3. The current transformer with insulation detection function according to claim 1, characterized in that, In the signal conditioning circuit (19), the operational amplifier U1 (8) is a high-gain and low-noise operational amplifier, and the capacitor C1 (6) is a ceramic capacitor, and the capacitance value is selected according to the frequency of the high-frequency interference signals to be filtered.
4. The current transformer with insulation detection function according to claim 1, characterized in that, In the comparator circuit (20), the resistance R3 (9) is accurately calculated and determined according to the required reference voltage value and the power supply voltage value.
5. The current transformer with insulation detection function according to claim 1, characterized in that, The alarm circuit (21) comprises a driving circuit, the driving circuit provides a suitable driving current for the light-emitting diode (12) or the buzzer (14) according to the low-level signal output by the comparator U2 (10).
6. The current transformer with insulation detection function according to claim 1, characterized in that, The insulation detection circuit and the current transformer body are connected by a shielded wire.
7. The current transformer with insulation detection function according to claim 1, characterized in that, The core material of the current transformer body is a soft magnetic alloy with high magnetic permeability; during the winding process of the winding assembly, the layers are isolated by an insulating material.