Wide-measurement range current transformer signal transmission system and transmission method
A signal transmission system and current transformer technology, which is applied in the field of electrical engineering measurement, can solve problems such as low signal-to-noise ratio and low signal measurement accuracy, and achieve high-precision measurement, improve signal-to-noise ratio, and high real-time performance
Inactive Publication Date: 2019-01-25
SHANDONG UNIV OF TECH
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[0004] However, the use of a single LPCT and the light intensity modulation method has the following disadvantages: the range of the voltage signal reflecting the bus current output by the LPCT using the sampling resistor is limited by the power supply voltage of the high-voltage side circuit. For example, if the high-voltage side circuit uses +5V power supply , then for the 5P20 precision measurement and protection integrated current transformer, when the rated current is 300A, for the protection multiple of 20, it means that the current signal in the range of 0~6000A should correspond to the current signal in the range of 0~5V The voltage signal is reflected, if the design circuit uses 5V peak-to-peak ( V pp ) dynamic range voltage to represent a current of 6000A, then for a rated current of 300A, a voltage of a dynamic range of 250mV is required to represent it, while a current of 15A (5% of a rated current) needs to be represented by a dynamic range of 12.5mV
[0005] Generally speaking, when the current transformer is in operation, due to the extremely small probability of failure, it is in use for measurement most of the time, and it can be seen from the above that when using such a small dynamic range signal to measure the 15A current , due to its low signal-to-noise ratio, the measurement accuracy of this signal is also low. It can be seen that for a current transformer that uses an LPCT to realize the integration of protection and measurement, it is necessary to ensure a large measurement range and a guarantee within this range. High accuracy, especially the measurement accuracy of small current, it is difficult to balance the two
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[0038] Figure 1~2 It is the best embodiment of the present invention, below in conjunction with attached Figure 1~2 The present invention will be further described.
[0039] Such as figure 1 As shown, a current transformer signal transmission system with a wide measurement range includes a high-voltage side and a low-voltage side, and the high-voltage side and the low-voltage side are connected by an optical fiber. , a signal conditioning module, an interval information judging module, a phase shifting module, an interval information judging module, a variable current limiting resistor module, and a signal drive module to be tested. The low voltage side includes a current interval photoelectric conversion module and a signal to be tested photoelectric conversion module.
[0040] In the high-voltage side, the output end of the LPCT is respectively connected to the input end of the rectification filter module and the input end of the signal conditioning module, the output en...
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The invention relates to a wide-measurement range current transformer signal transmission system and a transmission method and belongs to the field of electrical engineering measurement. The wide-measurement range current transformer signal transmission system comprises a high voltage side and a low voltage side connected by an optical fiber. The wide-measurement range current transformer signal transmission system is characterized in that the output ends of a current transformer are connected with the input ends of an interval information judging module and a signal conditioning module respectively; the output end of the signal conditioning module is connected with the input end of a to-be-tested signal driving module; the output ends of the interval information judging module is connected with the input ends of an interval information driving module and a variable current-limiting resistor module; and the variable current-limiting resistor module changes a resistance value accordingto different signals outputted by the interval information judging module, wherein the resistance value is outputted to the to-be-tested signal driving module. According to the wide-measurement rangecurrent transformer signal transmission system and the transmission method of the invention, the interval information driving module is adopted to judge the interval information of the output signalsof the current transformer; the waveform amplitude of signals to be tested is changed according to the interval information; and therefore, the signal-to-noise ratio of the signals to be tested undera small-amplitude condition can be improved.
Description
technical field [0001] The invention discloses a current transformer signal transmission system and a transmission method with a wide measurement range, belonging to the field of electrical engineering measurement. Background technique [0002] In the existing technology, the current transformer mainly plays the role of measurement and protection in the application process. At present, the current transformer for protection mostly uses air-core coils as the sensing device on the high-voltage side, and the current transformer for measurement mostly uses low-power current transformers. Transformer (Low Power Current Transformer, referred to as LPCT) is used as a sensor device on the high voltage side. Since LPCT has a very wide range of linearity, such as the current LPCT in a steady state, within the range of 20 times the rated current, its ratio error and phase The error has been able to meet the requirements of 0.2 level, so LPCT can fully take on the dual functions of meas...
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Login to View More IPC IPC(8): G01R15/18H04B10/25
CPCG01R15/18H04B10/25891
Inventor王玮张鹏张圣鹏贾明娜
OwnerSHANDONG UNIV OF TECH