CN105510777B - Differential pulse magnet insulation fault detection device - Google Patents
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Abstract
Description
技术领域technical field
本发明属于脉冲磁体绝缘故障探测技术领域，更具体地，涉及一种差分式脉冲磁体绝缘故障探测装置。The invention belongs to the technical field of pulse magnet insulation fault detection, and more specifically relates to a differential pulse magnet insulation fault detection device.
背景技术Background technique
强磁场为现代科学研究提供极端实验条件，是重要的科学实验平台。强磁场分为脉冲强磁场和稳态强磁场。脉冲强磁场可以提供更高强度的磁场，更能满足某些实验对高强度磁场的要求。但随着磁场强度不断提高，强磁场条件下产生的电、热、力极端条件有可能破坏磁体的绝缘；绝缘故障在萌芽初始往往较为比较微小，若不能及时发现，绝缘故障会逐渐扩大，最后破坏脉冲磁体甚至危及实验设备安全；因此需要对脉冲磁体绝缘状况进行实时监测，检测因绝缘破坏而产生的局部放电信号，以提前发现微小的绝缘故障，剔除故障磁体，保障脉冲强磁场装置的安全稳定运行。The strong magnetic field provides extreme experimental conditions for modern scientific research and is an important scientific experiment platform. Strong magnetic fields are divided into pulsed strong magnetic fields and steady-state strong magnetic fields. The pulsed strong magnetic field can provide a higher intensity magnetic field, which can better meet the requirements of some experiments for high-intensity magnetic fields. However, as the magnetic field strength continues to increase, the extreme conditions of electricity, heat, and force generated under strong magnetic field conditions may damage the insulation of the magnet; the insulation fault is often relatively small at the beginning of the germination, if it is not found in time, the insulation fault will gradually expand, and finally Destroying the pulse magnet may even endanger the safety of the experimental equipment; therefore, it is necessary to monitor the insulation status of the pulse magnet in real time and detect the partial discharge signal caused by insulation damage, so as to detect small insulation faults in advance, remove the faulty magnet, and ensure the safety of the pulse strong magnetic field device Stable operation.
脉冲磁体工作过程中，在刚开始发生绝缘破坏时，产生的局部放电信号比较微弱，电压值在毫伏级，频率达兆赫兹以上；而脉冲磁体本身的dB/dt信号达十几伏；要在脉冲磁体自身产生的背景信号中检测到混杂其中的局部放电信号比较困难；现有技术是利用示波器采集局部放电信号，可以做到较宽的带宽，较大的存储容量，而且示波器的采样率很高，可以达到500MHz甚至1GHz以上，但是示波器的采样位数不高，一般采样位数只有8位，无法从脉冲磁体的磁场变化所产生的电压信号(dB/dt)中分辨出局部放电信号。目前应用普遍的数据采集卡品种繁多、分辨率较高，但是采样速率中等，一般在几百千赫兹，少数能达到兆赫兹的采集卡较为昂贵，动辄成千上万元，成本太高；这两种方式都无法直接用于对脉冲磁体绝缘故障的微弱局部信号的采集。During the working process of the pulse magnet, when the insulation damage first occurs, the partial discharge signal generated is relatively weak, the voltage value is at the millivolt level, and the frequency is above megahertz; while the dB/dt signal of the pulse magnet itself reaches more than ten volts; It is difficult to detect the partial discharge signal mixed in the background signal generated by the pulsed magnet itself; the existing technology is to use the oscilloscope to collect the partial discharge signal, which can achieve wider bandwidth, larger storage capacity, and the sampling rate of the oscilloscope Very high, can reach 500MHz or even above 1GHz, but the number of sampling bits of the oscilloscope is not high, generally only 8 bits, and it is impossible to distinguish the partial discharge signal from the voltage signal (dB/dt) generated by the magnetic field change of the pulse magnet . At present, there are many types of commonly used data acquisition cards with high resolution, but the sampling rate is medium, generally in the hundreds of kilohertz, and a few acquisition cards that can reach megahertz are relatively expensive, costing tens of thousands of yuan, and the cost is too high; Neither of the two methods can be directly used to collect weak local signals of pulse magnet insulation faults.
发明内容Contents of the invention
针对现有技术的以上缺陷或改进需求，本发明提供了一种差分式脉冲磁体绝缘故障探测装置，其目的在于解决现有技术无法有效检测脉冲磁体绝缘故障初期的微弱局部放电信号的问题。In view of the above defects or improvement needs of the prior art, the present invention provides a differential pulse magnet insulation fault detection device, which aims to solve the problem that the prior art cannot effectively detect the weak partial discharge signal at the initial stage of the pulse magnet insulation fault.
为实现上述目的，按照本发明的一个方面，提出一种差分式脉冲磁体绝缘故障探测装置，包括第一探测线圈、第二探测线圈、电阻分压器和滤波器；In order to achieve the above object, according to one aspect of the present invention, a differential pulse magnet insulation fault detection device is proposed, including a first detection coil, a second detection coil, a resistor divider and a filter;
其中，第一探测线圈和第二探测线圈均沿脉冲磁体中心轴线设置，第一探测线圈设于脉冲磁体内，第二探测线圈设置在脉冲磁体外；Wherein, the first detection coil and the second detection coil are arranged along the central axis of the pulse magnet, the first detection coil is arranged inside the pulse magnet, and the second detection coil is arranged outside the pulse magnet;
两个探测线圈如上所述设置，当脉冲磁体的任何部位发生绝缘故障，两个探测线圈均可以探测到局部放电信号，而且第一探测线圈探测到的信号强度大于第二探测线圈探测到的信号强度；The two detection coils are set as described above. When any part of the pulse magnet has an insulation fault, the two detection coils can detect the partial discharge signal, and the signal intensity detected by the first detection coil is greater than that detected by the second detection coil. strength;
电阻分压器的两个固定端分别与第一探测线圈的正负两端相连；电阻分压器的可移动端作为输出正端；第二探测线圈的负端与第一探测线圈信号的负端相连，第二探测线圈的正端作为输出负端；滤波器的输入正端连接电阻分压器的可移动端，输入负端连接第二探测线圈的正端；The two fixed terminals of the resistor divider are respectively connected to the positive and negative ends of the first detection coil; the movable terminal of the resistor divider is used as the positive output terminal; the negative terminal of the second detection coil is connected to the negative terminal of the signal of the first detection coil. The positive terminal of the second detection coil is used as the output negative terminal; the input positive terminal of the filter is connected to the movable terminal of the resistor divider, and the input negative terminal is connected to the positive terminal of the second detection coil;
两个探测线圈与电阻分压器如上连接，使得第一探测线圈探测到的信号U1经过电阻分压器分压后，与第二探测线圈探测到的信号U2反向串联；两个探测线圈与电阻分压器形成差分结构，该差分结构输出信号U3；其中，电阻分压器分压系数k≤1；The two detection coils are connected to the resistor divider as above, so that the signal U 1 detected by the first detection coil is divided by the resistor divider, and then connected in reverse series with the signal U 2 detected by the second detection coil; The coil and the resistor divider form a differential structure, and the differential structure outputs a signal U 3 ; wherein, the voltage division coefficient of the resistor divider k≤1;
探测线圈探测到的脉冲磁体的磁场变化所产生的电压信号(dB/dt)根据脉冲磁体内部位置与探测线圈的距离成比例关系；在脉冲磁体无绝缘故障，没有局部放电信号的情况下，上述差分结构对两个探测线圈探测到的信号进行差分处理，输出信号U3＝kU1-U2；The voltage signal (dB/dt) generated by the magnetic field change of the pulse magnet detected by the detection coil is proportional to the distance between the internal position of the pulse magnet and the detection coil; when the pulse magnet has no insulation fault and no partial discharge signal, the above The differential structure performs differential processing on the signals detected by the two detection coils, and the output signal U 3 =kU 1 -U 2 ;
由于电路上存在杂散电感和杂散电容，U3的实际值不为零；通过调整电阻分压器，可使U3尽可能趋近于0以减小杂散信号对局部放电信号的干扰；在探测线圈检测到的信号包含局部放电信号的情况下，两个探测线圈探测到的局部放电信号的比例关系与脉冲磁体磁场变化所产生的背景电压dB/dt的比例关系不同，经过差分处理后，差分结构的输出信号U3中除了杂散信号之外，还包括局部放电信号；滤波器则用于滤除杂散信号，输出高频局部放电信号，根据该局部放电信号，则可定位出脉冲磁体内发生绝缘故障的点。Due to the presence of stray inductance and stray capacitance on the circuit, the actual value of U3 is not zero; by adjusting the resistor divider, U3 can be made as close to 0 as possible to reduce the interference of stray signals on partial discharge signals ; In the case that the signal detected by the detection coil contains a partial discharge signal, the proportional relationship of the partial discharge signal detected by the two detection coils is different from the proportional relationship of the background voltage dB/dt produced by the magnetic field change of the pulse magnet, after differential processing Finally, the output signal U 3 of the differential structure includes partial discharge signals in addition to stray signals; the filter is used to filter out stray signals and output high-frequency partial discharge signals. According to the partial discharge signals, the location can be The point at which an insulation fault occurs within the pulsed magnet.
优选的，上述装置中，第一探测线圈设在脉冲磁体内距脉冲磁体上端口2cm以内的位置，第二探测线圈设置在脉冲磁体外距磁体2cm～4cm处。Preferably, in the above device, the first detection coil is arranged inside the pulse magnet within 2 cm from the upper port of the pulse magnet, and the second detection coil is arranged outside the pulse magnet at a distance of 2 cm to 4 cm from the magnet.
优选的，上述滤波器采用截止频率在兆赫兹级的高通滤波器；由于脉冲磁体背景信号的幅值比局部放电信号的幅值大，采用截止频率在兆赫兹级的高通滤波器滤除背景信号，以消除对局部放电信号的干扰。Preferably, the above-mentioned filter adopts a high-pass filter with a cut-off frequency at the megahertz level; since the amplitude of the background signal of the pulsed magnet is larger than the amplitude of the partial discharge signal, a high-pass filter with a cut-off frequency at the megahertz level is used to filter out the background signal , to eliminate interference to the partial discharge signal.
优选的，上述差分式脉冲磁体绝缘故障探测装置，还包括示波装置，用于采集局部放电信号。Preferably, the above-mentioned differential pulse magnet insulation fault detection device further includes an oscilloscope device for collecting partial discharge signals.
总体而言，通过本发明所构思的以上技术方案与现有技术相比，能够取得下列有益效果：Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:
(1)本发明提供的差分式脉冲磁体绝缘故障探测装置，将两个不同位置探测线圈输出信号相减，以消除背景信号，较好地保留了局部放电信号，具有对微调局部放电信号探测灵敏度高的特点；(1) The differential pulse magnet insulation fault detection device provided by the present invention subtracts the output signals of two different position detection coils to eliminate the background signal, better retains the partial discharge signal, and has the ability to fine-tune the detection sensitivity of the partial discharge signal high characteristic
(2)本发明提供的差分式脉冲磁体绝缘故障探测装置，电路中没有用的运算放大器等集成器件，减小了噪声信号的干扰，具有电路简单，抗干扰性好的特点。(2) The differential pulse magnet insulation fault detection device provided by the present invention, integrated devices such as operational amplifiers which are not used in the circuit, reduce the interference of noise signals, and have the characteristics of simple circuit and good anti-interference.
附图说明Description of drawings
图1是本发明提供的差分式脉冲磁体绝缘故障探测装置的探测线圈与脉冲磁体位置关系示意图；Fig. 1 is a schematic diagram of the positional relationship between the detection coil and the pulse magnet of the differential pulse magnet insulation fault detection device provided by the present invention;
图2为本发明实施例提供的差分式脉冲磁体绝缘故障探测装置功能框图；Fig. 2 is a functional block diagram of a differential pulse magnet insulation fault detection device provided by an embodiment of the present invention;
图3为本发明实施例中探测到的局部放电信号波形示意图；3 is a schematic diagram of a partial discharge signal waveform detected in an embodiment of the present invention;
在所有附图中，相同的附图标记用来表示相同的元件或结构，其中：Throughout the drawings, the same reference numerals are used to designate the same elements or structures, wherein:
1-第一探测线圈，2-第二探测线圈，3-磁体绝缘故障点，4-脉冲磁体，5-脉冲磁体中轴线，11-第一探测线圈探测到的U1波形，12-杂散信号U3波形，13-绝缘故障产生的局部放电信号波形，1-first detection coil, 2-second detection coil, 3-magnet insulation fault point, 4-pulse magnet, 5-pulse magnet axis, 11-U1 waveform detected by the first detection coil, 12-spurious signal U 3 waveform, 13- Partial discharge signal waveform generated by insulation fault,
具体实施方式Detailed ways
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.
本发明实施例提供的差分式脉冲磁体绝缘故障探测装置，包括第一探测线圈、第二探测线圈、电阻分压器、高通滤波器和高采样率的示波器；The differential pulse magnet insulation fault detection device provided by the embodiment of the present invention includes a first detection coil, a second detection coil, a resistor divider, a high-pass filter and an oscilloscope with a high sampling rate;
如图1所示，第一探测线圈1和第二探测线圈2均沿脉冲磁体中心轴线设置，第一探测线圈1设于脉冲磁体4内，距脉冲磁体上端口2cm以内，第二探测线圈设置2在脉冲磁体外，距磁体2cm～4cm；As shown in Figure 1, the first detection coil 1 and the second detection coil 2 are all arranged along the central axis of the pulse magnet, the first detection coil 1 is arranged in the pulse magnet 4, within 2 cm from the upper port of the pulse magnet, and the second detection coil is arranged 2 Outside the pulse magnet, 2cm to 4cm away from the magnet;
如图2所示，实施例提供的差分式脉冲磁体绝缘故障探测装置里，电阻分压器的两个固定端分别与第一探测线圈1的正负两端相连；第二探测线圈2的负端与第一探测线圈信号的负端相连；高通滤波器的输入正端连接电阻分压器的可移动端，输入负端连接第二探测线圈2的正端；As shown in Figure 2, in the differential pulse magnet insulation fault detection device provided by the embodiment, the two fixed ends of the resistor divider are respectively connected to the positive and negative ends of the first detection coil 1; terminal is connected to the negative terminal of the first detection coil signal; the input positive terminal of the high-pass filter is connected to the movable terminal of the resistor divider, and the input negative terminal is connected to the positive terminal of the second detection coil 2;
第一探测线圈1探测到的信号U1经过电阻分压器分压后，与第二探测线圈2探测到的信号U2反向串联，形成差分结构，该差分结构输出信号U3；在脉冲磁体无绝缘故障，没有局部放电信号的情况下，高通滤波器的输入信号U3＝kU1-U2＝0；k为电阻分压器的分压系数；After the signal U1 detected by the first detection coil 1 is divided by a resistor divider, it is reversely connected in series with the signal U2 detected by the second detection coil 2 to form a differential structure, which outputs a signal U3 ; When the magnet has no insulation fault and there is no partial discharge signal, the input signal of the high-pass filter U3=kU1-U2=0; k is the voltage division coefficient of the resistor divider;
实施例中，脉冲磁体的绝缘故障发生在图1内3所示的位置，该绝缘故障点产生局部放电信号；本实施例中采用的探测线圈的线圈匝数40匝，导线采用0.2mm漆包线；采用的电阻分压器的电阻变化范围0～50kΩ；采用的高通滤波器的带宽0.1MHz～1GHz；采用的示波器的采样频率5GHz。In the embodiment, the insulation fault of the pulse magnet occurs at the position shown in 3 in Fig. 1, and the insulation fault point generates a partial discharge signal; the number of coil turns of the detection coil used in the present embodiment is 40 turns, and the wire adopts 0.2mm enameled wire; The resistance variation range of the resistor divider adopted is 0-50kΩ; the bandwidth of the high-pass filter adopted is 0.1MHz-1GHz; the sampling frequency of the oscilloscope adopted is 5GHz.
在绝缘故障发生局部放电的过程中，由于回路中存在杂散电感和杂散电容，U3＝kU1-U2≠0，通过调整电阻分压器的倍数使U3值尽可能的小；U3中既包含杂散信号又包含局部放电信号；In the process of partial discharge due to insulation faults, due to the stray inductance and stray capacitance in the circuit, U3=kU1-U2≠0, the value of U3 is made as small as possible by adjusting the multiple of the resistor divider; U3 contains both The stray signal also includes the partial discharge signal;
本实施例中采集到的波形如图3所示，图中标记：11为第一探测线圈探测到的脉冲磁体磁场变化所产生的背景电压信号dB/dt U1缩小了10倍的波形，12为杂散信号U3的波形，13为绝缘故障产生的局部放电信号；高通滤波器滤除波形12中的低频杂散信号，获取到的局部放电信号如波形13；波形13中，用A、B、C标注出为局部放电信号产生的位置，上述位置与实际绝缘故障点一致；在图3里，为便于观测，将第一探测线圈探测到的dB/dt信号U1缩小10倍。The waveform collected in the present embodiment is as shown in Figure 3, and the mark in the figure: 11 is the background voltage signal dB/dt U1 that the pulse magnet magnetic field change that the first detection coil detects produces the waveform that has been reduced by 10 times, and 12 is the waveform The waveform of the stray signal U3, 13 is the partial discharge signal generated by the insulation fault; the high-pass filter filters out the low-frequency stray signal in the waveform 12, and the obtained partial discharge signal is such as the waveform 13; in the waveform 13, use A, B, C marks the position where the partial discharge signal is generated, and the above position is consistent with the actual insulation fault point; in Figure 3, for the convenience of observation, the dB/dt signal U1 detected by the first detection coil is reduced by 10 times.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.
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| CN103913681A (en) * | 2014-03-24 | 2014-07-09 | 华北电力大学 | System and method for detecting partial discharge under high-frequency voltage |
| CN104569772B (en) * | 2014-12-18 | 2017-11-17 | 北京新能源汽车股份有限公司 | Electric high-voltage direct-current insulation detection circuit and method |
| CN104749498B (en) * | 2015-01-28 | 2018-12-04 | 西安交通大学 | A kind of detection of Portable PD On-Line and diagnostic device |
| CN104749508A (en) * | 2015-04-10 | 2015-07-01 | 国网上海市电力公司 | Online partial discharge detector of power capacitor |
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