A capacitive voltage transformer live detection device based on multiple signal acquisition

Abstract

The present invention provides a capacitive voltage transformer live detection device based on multiple signal collection, the live detection device includes a signal collection unit, a signal conditioning unit, an A / D conversion unit, a central control processing unit, a storage unit, a display unit and a key input unit; the live detection device collects relevant parameters of the capacitive voltage transformer when it is working under power, and after analysis and calculation, determines whether the capacitive voltage transformer is working normally, and can send out an alarm signal in time if there is a fault so that relevant staff can take necessary measures. The present invention provides a capacitive voltage transformer live detection device based on multiple signal collection, which can effectively and accurately detect the short-circuit fault and dielectric loss state of the internal coil of the voltage transformer.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power detection, and in particular relates to a capacitive voltage transformer live detection device based on multiple signal acquisition. Background Art

[0002] With the continuous development of power technology, the requirements for the safety and reliability of power systems are getting higher and higher. Capacitor voltage transformers are one of the important equipment for power system protection and measurement information collection. With the increasing application of capacitor voltage transformers in power systems, the state detection of capacitor voltage transformers has gradually received attention. At present, the detection methods for capacitor voltage transformers mainly include: power outage maintenance, equipment inspection, live detection and online monitoring. The existing live detection methods are mainly used for fault detection such as partial discharge and temperature rise, and cannot effectively and accurately detect the internal coil short circuit fault and dielectric loss state of the voltage transformer. Summary of the invention

[0003] The present invention provides a capacitive voltage transformer live detection device based on multiple signal acquisition, which can effectively and accurately detect the internal coil short-circuit fault and dielectric loss state of the voltage transformer.

[0004] The present invention specifically relates to a capacitive voltage transformer live detection device based on multiple signal acquisitions, the live detection device comprising a signal acquisition unit, a signal conditioning unit, an A / D conversion unit, a central control processing unit, a storage unit, a display unit and a key input unit, the signal acquisition unit, the signal conditioning unit, the A / D conversion unit and the central control processing unit are connected in sequence, the central control processing unit is also respectively connected to the storage unit, the display unit and the key input unit; the live detection device collects relevant parameters of the capacitive voltage transformer when it is working live, determines whether the capacitive voltage transformer is working normally after analysis and calculation, and can send out an alarm signal in time if there is a fault so that relevant staff can take necessary measures.

[0005] The key input unit combines with the storage unit and the display unit to complete the input of the factory status parameters of the capacitive voltage transformer.

[0006] The signal acquisition unit mainly acquires the primary side input voltage, secondary side output voltage, current flowing through the capacitor voltage divider and current flowing through the medium voltage electromagnetic unit of the capacitor voltage transformer. The primary side input voltage is acquired by a step-down transformer, the secondary side output voltage is directly acquired from the secondary side of the capacitor voltage transformer, and the current flowing through the capacitor voltage divider and the current flowing through the medium voltage electromagnetic unit are acquired by a current transformer.

[0007] The signal conditioning unit includes a signal amplification module and a signal filtering module. The signal amplification module adopts an AD706 operational amplifier and can adjust the amplification factor as needed; the filtering module adopts a secondary low-pass filter, which effectively suppresses high-frequency harmonics through two filterings to ensure that the output signal meets the working range of the A / D conversion unit.

[0008] The central control processing unit analyzes and calculates the collected signals, and then determines whether the capacitive voltage transformer fails:

[0009] If the ratio of the secondary side output voltage to the primary side input voltage becomes larger, the high voltage capacitor unit of the capacitive voltage transformer breaks down or the primary coil of the intermediate transformer is partially short-circuited;

[0010] If the ratio of the secondary side output voltage to the primary side input voltage becomes smaller, the medium voltage capacitor unit of the capacitive voltage transformer breaks down or the secondary coil of the intermediate transformer is partially short-circuited;

[0011] If the phase angle difference between the secondary side output voltage and the primary side input voltage becomes smaller or the ratio of the current flowing through the capacitor voltage divider to the current flowing through the medium voltage electromagnetic unit becomes smaller, the capacitive voltage transformer will suffer dielectric loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention is a schematic structural diagram of a capacitive voltage transformer live detection device based on multiple signal acquisition. DETAILED DESCRIPTION

[0013] The specific implementation of a capacitive voltage transformer live detection device based on multiple signal acquisition of the present invention is described in detail below with reference to the accompanying drawings.

[0014] like Figure 1 As shown, the live detection device of the present invention includes a signal acquisition unit, a signal conditioning unit, an A / D conversion unit, a central control processing unit, a storage unit, a display unit and a key input unit, wherein the signal acquisition unit, the signal conditioning unit, the A / D conversion unit and the central control processing unit are connected in sequence, and the central control processing unit is also respectively connected to the storage unit, the display unit and the key input unit; the live detection device collects relevant parameters of the capacitive voltage transformer when it is working under power, determines whether the capacitive voltage transformer is working normally after analysis and calculation, and can send out an alarm signal in time if there is a fault so that relevant staff can take necessary measures.

[0015] The key input unit combines with the storage unit and the display unit to complete the input of the factory status parameters of the capacitive voltage transformer.

[0016] The signal acquisition unit mainly acquires the primary side input voltage, secondary side output voltage, current flowing through the capacitor voltage divider and current flowing through the medium voltage electromagnetic unit of the capacitor voltage transformer. The primary side input voltage is acquired by a step-down transformer, the secondary side output voltage is directly acquired from the secondary side of the capacitor voltage transformer, and the current flowing through the capacitor voltage divider and the current flowing through the medium voltage electromagnetic unit are acquired by a current transformer.

[0017] The signal conditioning unit includes a signal amplification module and a signal filtering module. The signal amplification module adopts an AD706 operational amplifier and can adjust the amplification factor as needed; the filtering module adopts a secondary low-pass filter, which effectively suppresses high-frequency harmonics through two filterings to ensure that the output signal meets the working range of the A / D conversion unit.

[0018] The central control processing unit analyzes and calculates the collected signals, and then determines whether the capacitive voltage transformer fails:

[0019] If the ratio of the secondary side output voltage to the primary side input voltage becomes larger, the high voltage capacitor unit of the capacitive voltage transformer breaks down or the primary coil of the intermediate transformer is partially short-circuited;

[0020] If the ratio of the secondary side output voltage to the primary side input voltage becomes smaller, the medium voltage capacitor unit of the capacitive voltage transformer breaks down or the secondary coil of the intermediate transformer is partially short-circuited;

[0021] If the phase angle difference between the secondary side output voltage and the primary side input voltage becomes smaller or the ratio of the current flowing through the capacitor voltage divider to the current flowing through the medium voltage electromagnetic unit becomes smaller, the capacitive voltage transformer will suffer dielectric loss.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. A person skilled in the art should understand that the specific implementation of the present invention can be modified or replaced by equivalents, but these modifications or changes are within the scope of protection of the pending claims.

Claims

1. A capacitive voltage transformer live detection device based on multiple signal acquisition, characterized in that: The live detection device comprises a signal acquisition unit, a signal conditioning unit, an A / D conversion unit, a central control processing unit, a storage unit, a display unit and a key input unit. The signal acquisition unit, the signal conditioning unit, the A / D conversion unit and the central control processing unit are connected in sequence, and the central control processing unit is also connected to the storage unit, the display unit and the key input unit respectively; the live detection device collects relevant parameters of the capacitive voltage transformer when it is working under power, and determines whether the capacitive voltage transformer works normally after analysis and calculation. If there is a fault, an alarm signal can be issued in time so that relevant staff can take measures; The signal acquisition unit acquires the primary side input voltage, the secondary side output voltage, the current flowing through the capacitor voltage divider and the current flowing through the medium voltage electromagnetic unit of the capacitor voltage transformer, the primary side input voltage is acquired by a step-down transformer, the secondary side output voltage is directly acquired from the secondary side of the capacitor voltage transformer, and the current flowing through the capacitor voltage divider and the current flowing through the medium voltage electromagnetic unit are acquired by a current transformer; The central control processing unit analyzes and calculates the collected signals, and then determines whether the capacitive voltage transformer fails: If the ratio of the secondary side output voltage to the primary side input voltage becomes larger, the high voltage capacitor unit of the capacitive voltage transformer breaks down or the primary coil of the intermediate transformer is partially short-circuited; If the ratio of the secondary side output voltage to the primary side input voltage becomes smaller, the medium voltage capacitor unit of the capacitive voltage transformer breaks down or the secondary coil of the intermediate transformer is partially short-circuited; If the phase angle difference between the secondary side output voltage and the primary side input voltage becomes smaller or the ratio of the current flowing through the capacitor voltage divider to the current flowing through the medium voltage electromagnetic unit becomes smaller, the capacitive voltage transformer will suffer dielectric loss.

2. The capacitive voltage transformer live detection device based on multiple signal acquisition according to claim 1 is characterized in that: The key input unit combines with the storage unit and the display unit to complete the input of the factory status parameters of the capacitive voltage transformer.

3. The device for detecting a capacitive voltage transformer charged based on multiple signal acquisition according to claim 2 is characterized in that: The signal conditioning unit includes a signal amplification module and a signal filtering module. The signal amplification module adopts an AD706 operational amplifier and can adjust the amplification factor as needed; the filtering module adopts a secondary low-pass filter, which effectively suppresses high-frequency harmonics through two filterings to ensure that the output signal meets the working range of the A / D conversion unit.

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