CN106549371A - The method and apparatus for preventing PT ferromagnetic resonances from causing UFLS malfunction - Google Patents
The method and apparatus for preventing PT ferromagnetic resonances from causing UFLS malfunction Download PDFInfo
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- 238000005259 measurement Methods 0.000 claims description 6
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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Abstract
本发明实施例提供了一种防止PT铁磁谐振引起低频减载误动的方法和装置，所述方法包括：获取负序电压U2和综合谐波信息Uxb；判断负序电压U2和综合谐波信息Uxb是否异常，如果是发生PT铁磁谐振，闭锁低频减载；否则未发生PT铁磁谐振，开放低频减载。上述技术方案提出了一种防止PT铁磁谐振引起低频减载误动的方法和装置，能够利用负序电压幅值及综合谐波信息的特征识别PT发生PT铁磁谐振或故障，进而实现对低频减载闭锁。本发明实施例可以弥补传统低频减载逻辑的缺陷，能有效的防止PT铁磁谐振引起低频减载误动。
Embodiments of the present invention provide a method and device for preventing PT ferroresonance from causing low-frequency load shedding misoperation, the method includes: acquiring negative sequence voltage U 2 and comprehensive harmonic information U xb ; judging negative sequence voltage U 2 and Whether the comprehensive harmonic information U xb is abnormal, if PT ferromagnetic resonance occurs, lock low-frequency load shedding; otherwise, PT ferromagnetic resonance does not occur, open low-frequency load shedding. The above technical scheme proposes a method and device for preventing PT ferroresonance from causing low-frequency load shedding misoperation, which can identify PT ferroresonance or faults in PTs by using the negative sequence voltage amplitude and comprehensive harmonic information characteristics, and then realize Low frequency load shedding blocking. The embodiment of the present invention can make up for the defects of traditional low-frequency load shedding logic, and can effectively prevent PT ferromagnetic resonance from causing low-frequency load shedding misoperation.
Description
技术领域technical field
本发明涉及电力系统继电保护技术领域，尤其是指一种防止PT(电压互感器)铁磁谐振引起低频减载误动的方法和装置。The invention relates to the technical field of electric power system relay protection, in particular to a method and a device for preventing low-frequency load shedding maloperation caused by PT (voltage transformer) ferromagnetic resonance.
背景技术Background technique
在35kV及以下电压等级电力系统中常采用电磁式电压互感器。电磁式电压互感器包括对地电感和母线对地电容，并构成振荡回路。当电网发生冲击扰动时(例如开关突然合闸或母线发生瞬间弧光接地现象等)，都可能使一相或两相的对地电压瞬间提高，使得互感器的励磁电流突然增大而发生饱和，其等值励磁电感L相应减小，发生谐振。铁磁谐振会引起的电压波形畸变，可能会引起低频减载误动。Electromagnetic voltage transformers are often used in power systems with voltage levels of 35kV and below. The electromagnetic voltage transformer includes the inductance to the ground and the capacitance to the ground of the bus bar, and constitutes an oscillation circuit. When the power grid has an impact disturbance (such as the sudden closing of the switch or the instantaneous arcing grounding of the busbar, etc.), the ground voltage of one or two phases may increase instantaneously, causing the excitation current of the transformer to suddenly increase and saturate. Its equivalent excitation inductance L decreases accordingly, and resonance occurs. The voltage waveform distortion caused by ferromagnetic resonance may cause misoperation of low-frequency load shedding.
发明内容Contents of the invention
针对现有技术中存在的电磁式电压互感器可会在电网发生冲击扰动时引起低频减载误动，本发明实施例要解决的技术问题是提出一种防止PT铁磁谐振引起低频减载误动的方法和装置。In view of the fact that the electromagnetic voltage transformer in the prior art may cause low-frequency load shedding misoperation when the power grid has an impact disturbance, the technical problem to be solved in the embodiment of the present invention is to propose a method to prevent PT ferroresonance from causing low-frequency load shedding misoperation. method and device for moving.
为了解决上述问题，本发明实施例提出了一种防止PT铁磁谐振引起低频减载误动的方法，包括：In order to solve the above problems, the embodiment of the present invention proposes a method to prevent PT ferromagnetic resonance from causing low-frequency load shedding misoperation, including:
获取负序电压U2和综合谐波信息Uxb；Obtain negative sequence voltage U 2 and comprehensive harmonic information U xb ;
判断负序电压U2和综合谐波信息Uxb是否异常，如果是发生PT铁磁谐振，闭锁低频减载；否则未发生PT铁磁谐振，开放低频减载。Determine whether the negative sequence voltage U 2 and the comprehensive harmonic information U xb are abnormal. If PT ferromagnetic resonance occurs, lock the low-frequency load shedding; otherwise, if PT ferromagnetic resonance does not occur, open the low-frequency load shedding.
其中，判断负序电压U2是否异常具体包括：Among them, judging whether the negative sequence voltage U2 is abnormal specifically includes:
判断U2>Κ2是否成立，如果是则发生PT铁磁谐振；其中K2为负序电压门槛值。Judging whether U 2 >K 2 holds true, if so, PT ferromagnetic resonance occurs; where K 2 is the negative sequence voltage threshold.
其中，判断综合谐波信息Uxb是否异常具体包括：Wherein, judging whether the comprehensive harmonic information U xb is abnormal specifically includes:
判断Uxb>ΚUjb是否成立，如果是则发生PT铁磁谐振；其中Uxb为测频电压的综合谐波电压，Ujb为测频电压的基波电压，K为综合谐波与基波比值门槛值。Judging whether U xb > ΚU jb is established, if so, PT ferromagnetic resonance occurs; where U xb is the integrated harmonic voltage of the frequency measurement voltage, U jb is the fundamental wave voltage of the frequency measurement voltage, and K is the integrated harmonic and fundamental wave ratio threshold.
其中，所述综合谐波与基波比值门槛值K的取值为0.15～0.2。Wherein, the threshold value K of the ratio of the integrated harmonic to the fundamental wave is 0.15-0.2.
同时，本发明实施例还提出了一种防止PT铁磁谐振引起低频减载误动的装置，包括：At the same time, the embodiment of the present invention also proposes a device for preventing low-frequency load shedding misoperation caused by PT ferromagnetic resonance, including:
参数获取模块，用于获取负序电压U2和综合谐波信息Uxb；A parameter acquisition module, used to acquire the negative sequence voltage U 2 and the comprehensive harmonic information U xb ;
故障判断模块，用于判断负序电压U2和综合谐波信息Uxb是否异常，如果是发生PT铁磁谐振，闭锁低频减载；否则未发生PT铁磁谐振，开放低频减载。The fault judgment module is used to judge whether the negative sequence voltage U 2 and the comprehensive harmonic information U xb are abnormal. If PT ferromagnetic resonance occurs, the low-frequency load shedding is blocked; otherwise, the PT ferromagnetic resonance does not occur, and the low-frequency load shedding is enabled.
本发明的上述技术方案的有益效果如下：上述技术方案提出了一种防止PT铁磁谐振引起低频减载误动的方法和装置，能够利用负序电压幅值及综合谐波信息的特征识别PT发生PT铁磁谐振或故障，进而实现对低频减载闭锁。本发明实施例可以弥补传统低频减载逻辑的缺陷，能有效的防止PT铁磁谐振引起低频减载误动。The beneficial effects of the above-mentioned technical solution of the present invention are as follows: the above-mentioned technical solution proposes a method and device for preventing low-frequency load shedding misoperation caused by PT ferromagnetic resonance, which can identify PT PT ferromagnetic resonance or fault occurs, and then the low-frequency load reduction is realized. The embodiments of the present invention can make up for the defects of traditional low-frequency load shedding logic, and can effectively prevent PT ferromagnetic resonance from causing misoperation of low-frequency load shedding.
附图说明Description of drawings
图1为本发明实施例的防止PT铁磁谐振引起低频减载误动的方法的流程图。FIG. 1 is a flow chart of a method for preventing PT ferromagnetic resonance from causing low-frequency load shedding maloperation according to an embodiment of the present invention.
具体实施方式detailed description
为使本发明要解决的技术问题、技术方案和优点更加清楚，下面将结合附图及具体实施例进行详细描述。In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.
本发明实施例提出了一种防止PT铁磁谐振引起低频减载误动的方法和装置，利用了负序电压的幅值信息和三相电压的综合谐波信息来判别铁磁谐振；当发生PT铁磁谐振时能可靠闭锁低频减载，而未发生PT铁磁谐振时能快速开放低频减载。The embodiment of the present invention proposes a method and device for preventing low-frequency load shedding misoperation caused by PT ferroresonance, which utilizes the amplitude information of the negative sequence voltage and the comprehensive harmonic information of the three-phase voltage to distinguish ferroresonance; When PT ferromagnetic resonance occurs, it can reliably block low-frequency load shedding, and when PT ferromagnetic resonance does not occur, it can quickly open low-frequency load shedding.
基于PT铁磁谐振可能是分次谐波谐振或高次谐波谐振，因此本发明实施例中同时测量负序电压的幅值信息和三相电压的综合谐波信息，并以此来判别是否发生铁磁谐振；若发生PT铁磁谐振则闭锁低频减载，否则开放低频减载。这样可以防止由于PT铁磁谐波引起的错误的低频减载，防止误动。其中，分次谐波谐振时可以采用负序电压U2的幅值来判别，高次谐波谐振时可以采用综合谐波信息Uxb来判别；在正常时负序电压U2幅值和综合谐波信息Uxb均很小。Based on the PT ferromagnetic resonance may be sub-harmonic resonance or high-order harmonic resonance, so in the embodiment of the present invention, the amplitude information of the negative sequence voltage and the comprehensive harmonic information of the three-phase voltage are measured at the same time, and it is used to determine whether Ferromagnetic resonance occurs; if PT ferromagnetic resonance occurs, the low frequency load shedding is blocked, otherwise the low frequency load shedding is enabled. This prevents false low-frequency load shedding due to PT ferromagnetic harmonics and prevents misoperation. Among them, the magnitude of the negative sequence voltage U 2 can be used to judge the sub-harmonic resonance, and the comprehensive harmonic information U xb can be used to judge the high-order harmonic resonance; the amplitude of the negative sequence voltage U 2 and the comprehensive The harmonic information U xb is very small.
因此，本发明实施例的防止PT铁磁谐振引起低频减载误动的方法包括：Therefore, the method for preventing PT ferroresonance from causing low-frequency load shedding misoperation in the embodiment of the present invention includes:
获取负序电压U2和综合谐波信息Uxb；Obtain negative sequence voltage U 2 and comprehensive harmonic information U xb ;
判断负序电压U2和综合谐波信息Uxb是否异常，如果是发生PT铁磁谐振，闭锁低频减载；否则未发生PT铁磁谐振，开放低频减载。Determine whether the negative sequence voltage U 2 and the comprehensive harmonic information U xb are abnormal. If PT ferromagnetic resonance occurs, lock the low-frequency load shedding; otherwise, if PT ferromagnetic resonance does not occur, open the low-frequency load shedding.
进一步的，判断负序电压U2是否异常具体包括：Further, judging whether the negative sequence voltage U2 is abnormal specifically includes:
判断U2>Κ2是否成立，如果是则发生PT铁磁谐振；其中K2为负序电压门槛值。Judging whether U 2 >K 2 holds true, if so, PT ferromagnetic resonance occurs; where K 2 is the negative sequence voltage threshold.
进一步的，判断综合谐波信息Uxb是否异常具体包括：Further, judging whether the comprehensive harmonic information U xb is abnormal specifically includes:
判断Uxb>ΚUjb是否成立，如果是则发生PT铁磁谐振；其中Uxb为测频电压的综合谐波电压，Ujb为测频电压的基波电压，K为综合谐波与基波比值门槛值。Judging whether U xb > ΚU jb is established, if so, PT ferromagnetic resonance occurs; where U xb is the integrated harmonic voltage of the frequency measurement voltage, U jb is the fundamental wave voltage of the frequency measurement voltage, and K is the integrated harmonic and fundamental wave ratio threshold.
其中，综合谐波与基波比值门槛值K的取值为0.15～0.2。Wherein, the threshold value K of the ratio of the integrated harmonic to the fundamental wave is 0.15-0.2.
同时，本发明实施例还提出了一种防止PT铁磁谐振引起低频减载误动的装置，包括：At the same time, the embodiment of the present invention also proposes a device for preventing low-frequency load shedding misoperation caused by PT ferromagnetic resonance, including:
参数获取模块，用于获取负序电压U2和综合谐波信息Uxb；A parameter acquisition module, used to acquire negative sequence voltage U 2 and comprehensive harmonic information U xb ;
故障判断模块，用于判断负序电压U2和综合谐波信息Uxb是否异常，如果是发生PT铁磁谐振，闭锁低频减载；否则未发生PT铁磁谐振，开放低频减载。The fault judgment module is used to judge whether the negative sequence voltage U 2 and the comprehensive harmonic information U xb are abnormal. If PT ferromagnetic resonance occurs, the low-frequency load shedding is blocked; otherwise, the PT ferromagnetic resonance does not occur, and the low-frequency load shedding is enabled.
以上所述是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明所述原理的前提下，还可以作出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.
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- 2016-11-09 CN CN201610982923.0A patent/CN106549371A/en active Pending
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| EP1995856B1 (en) * | 1997-06-11 | 2014-02-26 | Abb Ab | A method for communication between a low potential level and a valve located on high voltage potential in a high voltage converter station as well as a device for such a communication |
| CN2702502Y (en) * | 2004-03-04 | 2005-05-25 | 保定浪拜迪电气股份有限公司 | A ferromagnetic resonance diagnostic eliminator of voltage transformer |
| CN104375025A (en) * | 2014-10-31 | 2015-02-25 | 国家电网公司 | Diagnostic method for ferromagnetic resonance in neutral non-grounding 10kV system |
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