Device and method for detecting internal fault of control winding of magnetic control type controllable reactor
阅读说明：本技术 磁控式可控电抗器的控制绕组内部故障检测装置及方法 (Device and method for detecting internal fault of control winding of magnetic control type controllable reactor ) 是由 石祥建 牟伟 韩兵 韩焦 钟高跃 吴龙 刘为群 陈松林 文继锋 苏家财 于 2019-09-09 设计创作，主要内容包括：本发明公开了一种磁控式可控电抗器的控制绕组内部故障检测装置及方法,包括第一电流传感元件,设于磁控式可控电抗器的控制绕组的正负极间过压保护支路中；和/或包括第二电流传感元件和第三电流传感元件,二者分别设于磁控式可控电抗器的控制绕组的正极对地过压保护支路和负极对地过压保护支路中；当所述第一电流传感元件,和/或第二电流传感元件和第三电流传感元件中检测到的电流满足设定故障电流特征时,则判定磁控式可控电抗器的控制绕组内部发生故障。本发明通过分别检测各过压保护支路的电流,并在电流符合控制绕组内部故障电流特征时判断电抗器控制绕组内部出现故障,实现了对磁控式电抗器控制绕组内部故障的准确、有效和快速判断。(the invention discloses a device and a method for detecting internal faults of a control winding of a magnetic control type controllable reactor, wherein the device comprises a first current sensing element, a second current sensing element and a third current sensing element, wherein the first current sensing element is arranged in an overvoltage protection branch circuit between the positive pole and the negative pole of the control winding of the magnetic control type controllable reactor; and/or the second current sensing element and the third current sensing element are respectively arranged in a positive pole earth overvoltage protection branch and a negative pole earth overvoltage protection branch of a control winding of the magnetic control type controllable reactor; and when the currents detected in the first current sensing element, the second current sensing element and the third current sensing element meet the set fault current characteristics, determining that a fault occurs in the control winding of the magnetic control type controllable reactor. According to the invention, the current of each overvoltage protection branch circuit is detected respectively, and the fault in the control winding of the reactor is judged when the current accords with the fault current characteristics in the control winding, so that the fault in the control winding of the magnetically controlled reactor is accurately, effectively and quickly judged.)
1. A control winding internal fault detection device of a magnetic control type controllable reactor is characterized by comprising:
The first current sensing element is arranged in an overvoltage protection branch circuit between the positive pole and the negative pole of a control winding of the magnetic control type controllable reactor;
and/or comprises:
the second current sensing element is arranged in the positive earth overvoltage protection branch of the control winding of the magnetic control type controllable reactor;
And
the third current sensing element is arranged in a negative pole earth overvoltage protection branch of a control winding of the magnetic control type controllable reactor;
The judging unit is used for receiving the currents of the first current sensing element and/or the second current sensing element and the third current sensing element; and when the currents detected in the first current sensing element, the second current sensing element and the third current sensing element meet the set fault current characteristics, determining that a fault occurs in the control winding of the magnetically controlled controllable reactor.
2. The internal fault detection device for the control winding of the magnetically controlled reactor according to claim 1, characterized in that: the fault current signature includes a current signature of a turn-to-turn short fault and a current signature of an internal ground fault.
3. The device for detecting the fault inside the control winding of the magnetically controlled reactor according to claim 1 or 2, wherein when the current detected in the first current sensing element meets the set fault current characteristic, it is determined that the fault occurs inside the control winding of the magnetically controlled reactor, specifically:
When the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1 in the first current sensing element, judging that the current I 1 exceeds a fault threshold value, and adding 1 to a counter N 1;
And if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set number N zj, the current i 1 is considered to meet the fault current characteristic of the turn-to-turn short circuit of the reactor control winding, and the turn-to-turn short circuit fault in the control winding is judged.
4. The device for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 3, wherein the set time is 18-22 ms.
5. the internal fault detection device for the control winding of the magnetically controlled reactor according to claim 1 or 2, characterized in that: when the currents detected in the second current sensing element and the third current sensing element meet the set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetic control type controllable reactor, specifically:
if the current i 21 in the second current sensing element or the current i 22 in the third current sensing element satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
and determining that the current i 21 or the current i 22 meets the fault current characteristic of grounding inside the control winding of the reactor, and judging that the grounding fault occurs inside the control winding.
6. the internal fault detection device for the control winding of the magnetically controlled reactor according to claim 1 or 2, characterized in that: when the currents detected in the first current sensing element, the second current sensing element and the third current sensing element meet the set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetically controlled controllable reactor, specifically:
when the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1 in the first current sensing element, judging that the current I 1 exceeds a fault threshold value, and adding 1 to a counter N 1;
If the counter N 1 meets the condition that 1 is added at every interval of set time, when the counter N 1 is more than or equal to the set time N zj, the current i 1 is considered to meet the fault current characteristic of turn-to-turn short circuit of the reactor control winding, and turn-to-turn short circuit fault inside the control winding is judged;
when the current i 21 in the second current sensing element or the current i 22 in the third current sensing element satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
And considering that the current i 21 or the current i 22 meets the fault current characteristic of the grounding inside the control winding of the reactor, and judging that the grounding fault and the turn-to-turn short circuit fault simultaneously occur inside the control winding.
7. a method for detecting internal faults of a control winding of a magnetically controlled reactor is characterized by comprising the following steps:
collecting an overvoltage protection branch current i 1 between the positive pole and the negative pole of a control winding of the magnetically controlled reactor;
And/or comprises:
Collecting the positive pole earth overvoltage protection branch current i 21 of the control winding of the magnetic control type controllable reactor, and
Collecting a negative pole earth overvoltage protection branch current i 22 of a control winding of the magnetic control type controllable reactor;
and when the current i 1 and/or the current i 21 and the current i 22 meet the set fault current characteristics, determining that a fault occurs in the control winding of the magnetic control type controllable reactor.
8. The method for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 7, wherein the method comprises the following steps: the fault current signature includes a current signature of a turn-to-turn short fault and a current signature of an internal ground fault.
9. the method for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 7, wherein when the current i 1 meets the set fault current characteristic, the method for determining the internal fault of the control winding of the magnetically controlled reactor specifically comprises the following steps:
When the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1, judging that the current I 1 exceeds a fault threshold value, and adding 1 to the counter N 1;
And if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set number N zj, the current i 1 is considered to meet the fault current characteristic of the turn-to-turn short circuit of the reactor control winding, and the turn-to-turn short circuit fault in the control winding is judged.
10. the method for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 9, wherein the method comprises the following steps: the set time is 18-22 ms.
11. the method for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 7, wherein when the current i 21 and the current i 22 meet the set fault current characteristics, the method for determining the internal fault of the control winding of the magnetically controlled reactor is characterized by comprising the following steps:
when the current i 21 or the current i 22 satisfies the following equation,
Wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
and determining that the current i 21 or the current i 22 meets the fault current characteristic of grounding inside the control winding of the reactor, and judging that the grounding fault occurs inside the control winding.
12. The method for detecting the internal fault of the control winding of the magnetically controlled reactor according to claim 7, wherein when the current i 1, the current i 21 and the current i 22 meet the set fault current characteristics, the method for determining the internal fault of the control winding of the magnetically controlled reactor specifically comprises the following steps:
when the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1, judging that the current I 1 exceeds a fault threshold value, and adding 1 to the counter N 1;
if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set time N zj, the current i 1 is considered to meet the fault current characteristic of the reactor for controlling the turn-to-turn short circuit of the winding;
when the current i 21 or the current i 22 satisfies the following equation,
Wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
And considering that the current i 21 or the current i 22 meets the fault current characteristic of the grounding inside the control winding of the reactor, and judging that the grounding fault and the turn-to-turn short circuit fault simultaneously occur inside the control winding.
Technical Field
the invention belongs to the technical field of protection of magnetic control type reactors, and particularly relates to a device and a method for detecting internal faults of a control winding of a magnetic control type controllable reactor.
background
When the extra-high voltage/extra-high voltage long-distance transmission line is in light load, the voltage at the tail end of the line is higher due to the obvious capacitance-rise effect of the line to ground capacitance charging, and the safe operation of power transmission and transformation equipment is damaged. The magnetic control type controllable reactor is used as one kind of controllable reactor, and the exciting system of the magnetic control type controllable reactor control winding continuously controls the DC exciting current to change the saturation of the iron core, so as to realize the change of reactance value and the continuous and smooth regulation of reactive power.
the existing magnetic control type controllable parallel reactor body mainly comprises a network side winding, a compensation winding and a control winding. The network side winding is directly connected with the ultrahigh voltage transmission line or the substation bus, and the compensation winding is connected with the filter device and the input end of the excitation system power rectification loop to provide an excitation power supply for the self-excitation type excitation system. The control winding is connected with the output end of the power rectifying loop of the excitation system, and the saturation degree and the corresponding reactance value of the iron core of the reactor body are determined by the size of the direct-current excitation current flowing into the control winding.
because the control winding adopts a structure that 2 windings are coupled with the same-phase network side winding in a reverse series connection (then three phases are connected in parallel), the power frequency alternating current induction voltages of the 2 windings in the reverse series connection are cancelled out normally, and the control winding does not present alternating voltage outwards. However, once a fault occurs inside the control winding (such as turn-to-turn short circuit, grounding of the internal winding, or flashover of the winding to the ground), a very high power frequency overvoltage (several kV to ten and several kV) is generated between the positive electrode and the negative electrode of the dc circuit connected to the control winding, and the high power frequency overvoltage is generated between the dc circuit (positive electrode or negative electrode) and the ground. In order to prevent the damage of overvoltage generated by internal fault of the control winding to the excitation system, on one hand, a positive pole earth overvoltage protection element, a negative pole earth overvoltage protection element and a positive and negative pole overvoltage protection element are required to be arranged at the output end of a rectification loop of the excitation system, and overvoltage energy is absorbed when the control winding is in fault; on the other hand, the reactor needs to be cut off from the power grid quickly, and overvoltage energy continuous action is avoided. The magnetically controlled reactor belongs to a typical high leakage reactance transformer type, the short circuit impedance can reach 0.4-0.6 pu, and the electric quantity of a grid side winding after the fault occurs in the control winding has no obvious electric fault characteristic, so that the fault is difficult to detect by a conventional protection means, and therefore, the fault in the control winding needs to be quickly detected by a special effective means, the reactor is ensured to be cut off from a power grid before the limit bearing capacity of an overvoltage protection element is reached, and the serious damage to the reactor equipment and the personnel of operators is avoided.
The technical data disclosed in the prior art relate to a detection method (such as CN200810105712.4 and CN201611160904.6) for flashover of an excitation winding sleeve of a magnetically controlled reactor, the method disclosed in the above document only judges whether faults such as flashover of the excitation winding sleeve and grounding in a winding occur or not by the existence of an output signal of a ground current sensing device, the judgment method is simple, current characteristics suitable for different faults in a control winding are not considered, and the problems of misjudgment and protection maloperation are possibly caused when a current sensor is damaged, a sampling loop is abnormal or a sampling system is interfered; meanwhile, the method disclosed by the above document judges the fault only by collecting a single grounding point current signal, and only a total grounding current signal can be obtained, which is not beneficial to deep analysis and grasp of fault reasons and a fault development process; and the grounding point current sensor can not detect current when the turn-to-turn short circuit fault of the control winding occurs, and the method can not be used for detecting and identifying the turn-to-turn fault.
disclosure of Invention
in order to solve the problems, the invention provides a device and a method for detecting faults inside a control winding of a magnetically controlled reactor.
In order to achieve the technical purpose and achieve the technical effects, the invention is realized by the following technical scheme:
in a first aspect, the present invention provides a device for detecting an internal fault of a control winding of a magnetically controlled reactor, including:
the first current sensing element is arranged in an overvoltage protection branch circuit between the positive pole and the negative pole of a control winding of the magnetic control type controllable reactor;
And/or comprises:
the second current sensing element is arranged in the positive earth overvoltage protection branch of the control winding of the magnetic control type controllable reactor; and
The third current sensing element is arranged in a negative pole earth overvoltage protection branch of a control winding of the magnetic control type controllable reactor;
The judging unit is used for receiving the currents of the first current sensing element and/or the second current sensing element and the third current sensing element; and when the currents detected in the first current sensing element, the second current sensing element and the third current sensing element meet the set fault current characteristics, determining that a fault occurs in the control winding of the magnetically controlled controllable reactor.
Optionally, the fault current signature comprises a current signature of a turn-to-turn short fault and a current signature of an internal ground fault.
optionally, when the current detected in the first current sensing element meets a set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetron type controllable reactor, specifically:
When the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1 in the first current sensing element, judging that the current I 1 exceeds a fault threshold value, and adding 1 to a counter N 1;
And if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set number N zj, the current i 1 is considered to meet the fault current characteristic of the turn-to-turn short circuit of the reactor control winding, and the turn-to-turn short circuit fault in the control winding is judged.
optionally, the set time is 18-22 ms.
optionally, when the currents detected in the second current sensing element and the third current sensing element satisfy a set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetically controlled controllable reactor, specifically:
If the current i 21 in the second current sensing element or the current i 22 in the third current sensing element satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
and determining that the current i 21 or the current i 22 meets the fault current characteristic of grounding inside the control winding of the reactor, and judging that the grounding fault occurs inside the control winding.
optionally, when the currents detected in the first current sensing element, the second current sensing element, and the third current sensing element satisfy a set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetron type controllable reactor, specifically:
when the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1 in the first current sensing element, judging that the current I 1 exceeds a fault threshold value, and adding 1 to a counter N 1;
if the counter N 1 meets the condition that 1 is added at every interval of set time, when the counter N 1 is more than or equal to the set time N zj, the current i 1 is considered to meet the fault current characteristic of turn-to-turn short circuit of the reactor control winding, and turn-to-turn short circuit fault inside the control winding is judged;
when the current i 21 in the second current sensing element or the current i 22 in the third current sensing element satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
The current i 21 or the current i 22 is determined to meet the fault current characteristic of grounding inside the reactor control winding;
and judging that the ground fault and the turn-to-turn short circuit fault simultaneously occur in the control winding.
In a second aspect, the invention provides a method for detecting an internal fault of a control winding of a magnetically controlled controllable reactor, which comprises the following steps:
Collecting an overvoltage protection branch current i 1 between the positive pole and the negative pole of a control winding of the magnetically controlled reactor;
and/or comprises:
collecting the positive pole earth overvoltage protection branch current i 21 of the control winding of the magnetic control type controllable reactor, and
collecting a negative pole earth overvoltage protection branch current i 22 of a control winding of the magnetic control type controllable reactor;
and when the current i 1 and/or the current i 21 and the current i 22 meet the set fault current characteristics, determining that a fault occurs in the control winding of the magnetic control type controllable reactor.
optionally, the fault current signature comprises a current signature of a turn-to-turn short fault and a current signature of an internal ground fault.
Optionally, when the current i 1 meets the set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetron type controllable reactor, specifically:
when the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1, judging that the current I 1 exceeds a fault threshold value, and adding 1 to the counter N 1;
And if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set number N zj, the current i 1 is considered to meet the fault current characteristic of the turn-to-turn short circuit of the reactor control winding, and the turn-to-turn short circuit fault in the control winding is judged.
optionally, the set time is 18-22 ms.
optionally, when the current i 21 and the current i 22 satisfy the set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetron type controllable reactor, specifically:
when the current i 21 or the current i 22 satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
And determining that the current i 21 or the current i 22 meets the fault current characteristic of grounding inside the control winding of the reactor, and judging that the grounding fault occurs inside the control winding.
optionally, when the current i 1, the current i 21 and the current i 22 satisfy the set fault current characteristic, it is determined that a fault occurs inside a control winding of the magnetron type controllable reactor, specifically:
When the previous sampling value is smaller than I 1th and the current sampling value is larger than I 1th in adjacent sampling points of the current I 1, judging that the current I 1 exceeds a fault threshold value, and adding 1 to the counter N 1;
if the counter N 1 meets the condition that 1 is added at every interval set time, when the counter N 1 is more than or equal to the set time N zj, the current i 1 is considered to meet the fault current characteristic of the reactor for controlling the turn-to-turn short circuit of the winding;
When the current i 21 or the current i 22 satisfies the following equation,
wherein I rms is the cycle effective value of current I 21 or current I 22, I h1 is the fundamental component effective value of current I 21 or current I 22, I dc is the direct current component value of current I 21 or current I 22, I 2th is the judgment threshold value of the current cycle effective value, I 2th1 is the judgment threshold value of the fundamental component effective value, and I 2th0 is the judgment threshold value of the direct current component, and the three can be set;
The current i 21 or the current i 22 is determined to meet the fault current characteristic of grounding inside the reactor control winding;
and judging that the ground fault and the turn-to-turn short circuit fault simultaneously occur in the control winding.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a device and a method for detecting faults inside a control winding of a magnetically controlled reactor.
drawings
in order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which:
fig. 1 is a layout diagram of current sensing elements provided in respective overvoltage protection branches in an embodiment of the present invention;
FIG. 2 is a schematic waveform diagram of a current i1 when a magnetron controllable reactor controls an inter-turn short circuit in a winding according to an embodiment of the invention;
FIG. 3 is a schematic waveform diagram of a current i21 or i22 when the internal ground fault of a control winding of the magnetically controlled reactor is detected in one embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of the invention.
The following detailed description of the principles of the invention is provided in connection with the accompanying drawings.