CN104913829A - Single crystal silicon piezoresistive type online oil level detector - Google Patents
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Abstract
本发明涉及一种单晶硅压阻式在线油位检测仪，包括依次连接的测量电路、信号处理电路和显示器，所述测量电路为由四个单晶硅压阻式传感器和电源构成的电桥测量电路，所述单晶硅压阻式传感器安装于换流变压器的油箱底部放油阀位置，获得放油阀位置的压力信号，通过信号处理电路进行放大、温度补偿、模数转换和标度变换后得到油面的高度。与现有技术相比，本发明具有快递准确检测、结构简单、可靠性强、成本低、安装方便等优点。
The invention relates to a single crystal silicon piezoresistive online oil level detector, which comprises a measurement circuit, a signal processing circuit and a display connected in sequence, and the measurement circuit is an electric circuit composed of four single crystal silicon piezoresistive sensors and a power supply. The bridge measurement circuit, the single crystal silicon piezoresistive sensor is installed at the position of the oil discharge valve at the bottom of the oil tank of the converter transformer to obtain the pressure signal of the oil discharge valve position, and the signal processing circuit performs amplification, temperature compensation, analog-to-digital conversion and calibration The height of the oil surface is obtained after degree conversion. Compared with the prior art, the present invention has the advantages of accurate express delivery detection, simple structure, strong reliability, low cost, convenient installation and the like.
Description
技术领域technical field
本发明涉及一种油位检测仪，尤其是涉及一种单晶硅压阻式在线油位检测仪。The invention relates to an oil level detector, in particular to a single crystal silicon piezoresistive online oil level detector.
背景技术Background technique
直流特高压、超高压输电工程在我国得到了广泛的应用，直流输电工程输送容量大，距离远，具有优良的调节性能，是实现大电网互联以及能源通道的关键技术。换流变压器是直流输电工程核心设备之一，为换流设备提供稳定的换相电源，对直流输电的稳定性起到至关重要的作用，换流变压器一般采用单相双绕组型式，一座常规的+-500kV换流站设计需要12台，+/-800kV特高压换流站则高达24台，单台换流变容量达到297.5MVA(ex：TCH146DR/ABB)，绝缘介质采用油绝缘，单台油量达到106800L，换流变压器运行环境复杂，短路阻抗大，同时承受交直流电压应力，运行中存在特征谐波和非特征谐波电流。换流变油位监视一般采用机械式油位计，安装于油枕侧方，此外通过换流变端子箱将油位信号上传至控制室监控后台。换流变高度达6米左右，此外由于高度阻挡，实际运行中对于油位计位置观测较为困难，同时，后台上传的油位信号可能由于二次回路故障导致数据错误，无法正确监视换流变油位。DC UHV and EHV transmission projects have been widely used in my country. DC transmission projects have large transmission capacity, long distances, and excellent regulation performance. They are the key technologies to realize the interconnection of large power grids and energy channels. The converter transformer is one of the core equipment of the DC transmission project. It provides a stable commutation power supply for the converter equipment and plays a vital role in the stability of the DC transmission. The converter transformer generally adopts a single-phase double-winding type. A conventional The +-500kV converter station design requires 12 units, and the +/-800kV UHV converter station has as many as 24 units. The single converter capacity reaches 297.5MVA (ex: TCH146DR/ABB). The oil volume of the transformer reaches 106800L. The operating environment of the converter transformer is complex, the short-circuit impedance is large, and it bears AC and DC voltage stress at the same time. There are characteristic harmonics and non-characteristic harmonic currents during operation. The oil level monitoring of the converter generally adopts a mechanical oil level gauge, which is installed on the side of the oil conservator. In addition, the oil level signal is uploaded to the monitoring background of the control room through the terminal box of the converter. The height of the converter is about 6 meters. In addition, due to the height barrier, it is difficult to observe the position of the oil level gauge in actual operation. At the same time, the oil level signal uploaded in the background may cause data errors due to secondary circuit failures, and the converter cannot be monitored correctly. oil level.
发明内容Contents of the invention
本发明的目的就是为了克服上述现有技术存在的缺陷而提供一种单晶硅压阻式在线油位检测仪，具有快递准确检测、结构简单、可靠性强、成本低、安装方便等优点。The purpose of the present invention is to provide a monocrystalline silicon piezoresistive online oil level detector in order to overcome the defects of the above-mentioned prior art, which has the advantages of express delivery and accurate detection, simple structure, high reliability, low cost, and convenient installation.
本发明的目的可以通过以下技术方案来实现：The purpose of the present invention can be achieved through the following technical solutions:
一种单晶硅压阻式在线油位检测仪包括依次连接的测量电路、信号处理电路和显示器，所述测量电路为由四个单晶硅压阻式传感器和电源构成的电桥测量电路，所述单晶硅压阻式传感器安装于换流变压器的油箱底部放油阀位置，获得放油阀位置的压力信号，通过信号处理电路进行放大、温度补偿、模数转换和标度变换后得到油面的高度。A single crystal silicon piezoresistive online oil level detector includes a measurement circuit, a signal processing circuit and a display connected in sequence, the measurement circuit is a bridge measurement circuit composed of four single crystal silicon piezoresistive sensors and a power supply, The monocrystalline silicon piezoresistive sensor is installed at the position of the oil discharge valve at the bottom of the oil tank of the converter transformer to obtain a pressure signal at the position of the oil discharge valve, which is obtained after amplification, temperature compensation, analog-to-digital conversion and scale conversion through a signal processing circuit. The height of the oil level.
所述单晶硅压阻式传感器为P型单晶硅压阻式传感器。The single crystal silicon piezoresistive sensor is a P-type single crystal silicon piezoresistive sensor.
所述信号处理电路包括依次连接的前置放大电路、温度补偿电路、模数转换电路和处理器，所述前置放大电路连接测量电路，所述处理器连接显示器。The signal processing circuit includes a preamplifier circuit, a temperature compensation circuit, an analog-to-digital conversion circuit and a processor connected in sequence, the preamplifier circuit is connected to a measurement circuit, and the processor is connected to a display.
所述温度补偿电路包括第一电阻、第二电阻、第三电阻、第四电阻、调零电阻、补偿电阻和二极管，所述第一电阻、第二电阻、第四电阻、第三电阻、调零电阻和第一电阻依次连接后形成闭环，所述补偿电阻与第二电阻并联，所述二极管的阴极连接第一电阻与第二电阻的接点，所述调零电阻与第三电阻的接点、第二电阻与第四电阻的接点为电压输入端，并连接前置放大电路，所述二极管的阳极、第三电阻与第四电阻的接点为电压输出端，并连接模数转换电路。The temperature compensation circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a zeroing resistor, a compensation resistor and a diode, the first resistor, the second resistor, the fourth resistor, the third resistor, the adjusting resistor The zero resistance and the first resistance are connected in sequence to form a closed loop, the compensation resistance is connected in parallel with the second resistance, the cathode of the diode is connected to the junction of the first resistance and the second resistance, the junction of the zero adjustment resistance and the third resistance, The junction of the second resistor and the fourth resistor is the voltage input end, and is connected to the preamplifier circuit; the anode of the diode, and the junction of the third resistor and the fourth resistor are the voltage output end, and is connected to the analog-to-digital conversion circuit.
还包括连接显示器的无线发射器，所述无线发射器通过无线网络连接远程监控平台。It also includes a wireless transmitter connected to the display, and the wireless transmitter is connected to a remote monitoring platform through a wireless network.
还包括连接显示器的声光报警器。Also includes an audible and visual alarm connected to the display.
与现有技术相比，本发明具有以下优点：Compared with the prior art, the present invention has the following advantages:
1)克服了机械师油位计观察困难和存在二次回路故障的缺陷，可以对运行中的换流变压器实际绝缘油位进行快速准确的检测，对换流变故障在线诊断提供了可靠的参数。1) It overcomes the difficulty of observing the oil level gauge of the mechanic and the defects of the secondary circuit fault, can quickly and accurately detect the actual insulation oil level of the converter transformer in operation, and provides reliable parameters for the online diagnosis of converter transformer faults .
2)P型单晶硅压阻式传感器测量精度较高，同时温度补偿电路克服了温度引起的零漂误差，保证测量数据的精准，可靠性强。2) The P-type monocrystalline silicon piezoresistive sensor has high measurement accuracy, and the temperature compensation circuit overcomes the zero drift error caused by temperature to ensure the accuracy and reliability of the measurement data.
3)结构简单，成本低，安装便捷。3) The structure is simple, the cost is low, and the installation is convenient.
附图说明Description of drawings
图1为本发明整体结构示意图；Fig. 1 is a schematic diagram of the overall structure of the present invention;
图2为P型单晶硅压阻式传感器结构示意图；Fig. 2 is a schematic structural diagram of a P-type single crystal silicon piezoresistive sensor;
图3为电桥测量电路示意图；Fig. 3 is a schematic diagram of the bridge measurement circuit;
图4为温度补偿电路示意图。Figure 4 is a schematic diagram of the temperature compensation circuit.
图中：1、电桥测量电路，2、信号处理电路，3、显示器，4、无线发射器，5、远程监控平台，6、声光报警器，7、P型单晶硅条，8、内引线，9、焊接电极，10、外引线，11、壳体，21、前置放大电路，22、温度补偿电路，23、模数转换电路，24、处理器，R1、第一电阻，R2、第二电阻，R3、第三电阻，R4、第四电阻，Rs、调零电阻，Rp、补偿电阻，VD、二极管，E、电源，U0、测量电路输出的压力信号，U1、前置放大电路输出的压力信号，U、温度补偿电路输出的压力信号。In the figure: 1. Bridge measurement circuit, 2. Signal processing circuit, 3. Display, 4. Wireless transmitter, 5. Remote monitoring platform, 6. Sound and light alarm, 7. P-type monocrystalline silicon strip, 8. Inner lead wire, 9, welding electrode, 10, outer lead wire, 11, housing, 21, preamplifier circuit, 22, temperature compensation circuit, 23, analog-to-digital conversion circuit, 24, processor, R1, first resistor, R2 , the second resistance, R3, the third resistance, R4, the fourth resistance, Rs, the zeroing resistance, Rp, the compensation resistance, VD, the diode, E, the power supply, U 0 , the pressure signal output by the measuring circuit, U 1 , the front Set the pressure signal output by the amplifying circuit, U, the pressure signal output by the temperature compensation circuit.
具体实施方式Detailed ways
下面结合附图和具体实施例对本发明进行详细说明。本实施例以本发明技术方案为前提进行实施，给出了详细的实施方式和具体的操作过程，但本发明的保护范围不限于下述的实施例。The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.
如图1所示，一种单晶硅压阻式在线油位检测仪包括依次连接的测量电路、信号处理电路2、显示器3、无线发射器4和声光报警器6，如图3所示，测量电路为由四个单晶硅压阻式传感器和电源E构成的电桥测量电路1，单晶硅压阻式传感器安装于换流变压器的油箱底部放油阀位置，获得放油阀位置的压力信号，即测量电路输出的压力信号U0，通过信号处理电路2进行放大、温度补偿、模数转换和标度变换后得到油面的高度，在显示器3中显示油面高度，无线发射器4连接显示器3，并通过无线网络连接远程监控平台5，进行数据的传送，声光报警器6连接显示器3可进行报警。As shown in Figure 1, a single crystal silicon piezoresistive online oil level detector includes a measurement circuit, a signal processing circuit 2, a display 3, a wireless transmitter 4 and an audible and visual alarm 6 connected in sequence, as shown in Figure 3 , the measurement circuit is a bridge measurement circuit 1 composed of four monocrystalline silicon piezoresistive sensors and a power supply E. The single crystal silicon piezoresistive sensor is installed at the position of the oil discharge valve at the bottom of the oil tank of the converter transformer to obtain the position of the oil discharge valve The pressure signal, that is, the pressure signal U 0 output by the measurement circuit, is amplified, temperature compensated, analog-to-digital converted, and scaled by the signal processing circuit 2 to obtain the height of the oil level, which is displayed on the display 3 and wirelessly transmitted The device 4 is connected to the display 3, and is connected to the remote monitoring platform 5 through a wireless network for data transmission, and the sound and light alarm 6 is connected to the display 3 for alarming.
其中，单晶硅压阻式传感器为测量精度较高的P型单晶硅压阻式传感器，如图2所示，P型单晶硅压阻式传感器包括壳体11以及设于壳体11内的P型单晶硅条7、两条内引线8、两个焊接电极9和两条外引线10，P型单晶硅条7端部、内引线8、焊接电极9和外引线10依次连接。Among them, the single crystal silicon piezoresistive sensor is a P-type single crystal silicon piezoresistive sensor with high measurement accuracy. As shown in Figure 2, the P-type single crystal silicon piezoresistive sensor includes a housing 11 and a housing 11 The inner P-type monocrystalline silicon strip 7, two inner leads 8, two welding electrodes 9 and two outer leads 10, the end of the P-type monocrystalline silicon strip 7, the inner leads 8, the welding electrodes 9 and the outer leads 10 in sequence connect.
信号处理电路2包括依次连接的前置放大电路21、温度补偿电路22、模数转换电路23和处理器24，前置放大电路21连接电桥测量电路1，处理器24连接显示器3。The signal processing circuit 2 includes a preamplifier circuit 21 , a temperature compensation circuit 22 , an analog-to-digital conversion circuit 23 and a processor 24 connected in sequence. The preamplifier circuit 21 is connected to the bridge measurement circuit 1 , and the processor 24 is connected to the display 3 .
如图4所示，温度补偿电路22包括第一电阻R1、第二电阻R2、第三电阻R3、第四电阻R4、调零电阻Rs、补偿电阻和二极管VD，第一电阻R1、第二电阻R2、第四电阻R4、第三电阻R3、调零电阻Rs和第一电阻R1依次连接后形成闭环，补偿电阻与第二电阻R2并联，二极管VD的阴极连接第一电阻R1与第二电阻R2的接点，调零电阻Rs与第三电阻R3的接点、第二电阻R2与第四电阻R4的接点为电压输入端，并连接前置放大电路21，前置放大电路输出的压力信号U1输入温度补偿电路22，二极管VD的阳极、第三电阻R3与第四电阻R4的接点为电压输出端，并连接模数转换电路23，温度补偿电路输出的压力信号U输入模数转换电路23。As shown in Figure 4, the temperature compensation circuit 22 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a zeroing resistor Rs, a compensation resistor and a diode VD, the first resistor R1, the second resistor R2, the fourth resistor R4, the third resistor R3, the zeroing resistor Rs and the first resistor R1 are connected in sequence to form a closed loop, the compensation resistor is connected in parallel with the second resistor R2, and the cathode of the diode VD is connected to the first resistor R1 and the second resistor R2 The contact of the zero-adjusting resistor Rs and the third resistor R3, the contact of the second resistor R2 and the fourth resistor R4 are the voltage input terminals, and are connected to the preamplifier circuit 21 , and the pressure signal U1 output by the preamplifier circuit is input The temperature compensation circuit 22 , the anode of the diode VD, and the junction of the third resistor R3 and the fourth resistor R4 are voltage output terminals, and are connected to the analog-to-digital conversion circuit 23 , and the pressure signal U output by the temperature compensation circuit is input to the analog-to-digital conversion circuit 23 .
处理器24获得放大、温度补偿、数模转换后的压力信号，计算获得压强p，进而通过公式p＝ρgh，得到放油阀部位与油面的高度h，ρ为液体密度，g为重力加速度，从而计算出换流变压器的油面位置。Processor 24 obtains the pressure signal after amplification, temperature compensation, and digital-to-analog conversion, calculates the pressure p, and then obtains the height h between the oil discharge valve and the oil surface through the formula p=ρgh, where ρ is the liquid density, and g is the acceleration of gravity , so as to calculate the oil level position of the converter transformer.
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| CN110779597A (en) * | 2019-11-13 | 2020-02-11 | 国网甘肃省电力公司检修公司 | High-precision measuring device and method for liquid level of transformer oil tank based on pressure sensor |
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| CN106441403A (en) * | 2016-09-19 | 2017-02-22 | 苏州戎维邦信息技术有限公司 | Method for zeroing initial null voltage of bridge sensor |
| CN106441403B (en) * | 2016-09-19 | 2019-03-08 | 苏州戎维邦信息技术有限公司 | Bridge type magnetic sensor initial zero position voltage adjusting zero method |
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