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1. 发明申请

US20220271527A1 TRANSFORMER OVERCURRENT PROTECTION 有权
公开(公告)号：US20220271527A1
公开(公告)日：2022-08-25
申请号：US17677879
申请日：2022-02-22
申请人： S&C Electric Company
发明人： Martin T. Bishop , Stephen E. Williams , Marcelo Perez
IPC分类号： H02H7/045 , G01R31/62 , H01F27/40
摘要： A system and method for determining when an electronic interrupting device will open in response to detecting overcurrent, where the interrupting device protects a transformer in a power distribution network. The method includes obtaining a time/current through fault protection curve that is defined by a plurality of time/current points for the transformer that identifies when the transformer may experience thermal or mechanical damage in response to a certain current flow over a certain time in the transformer windings, selecting a time multiplier, and determining an operating curve for the interrupting device by multiplying the multiplier and a time portion of each of the plurality of time/current points on the through fault protection curve, where the operating curve identifies when the interrupting device will open in response to a certain current flow over a certain time.

2. 发明授权

US11411390B2 Secure and dependable restricted earth fault protection for electric power generators and transformers 有权
公开(公告)号：US11411390B2
公开(公告)日：2022-08-09
申请号：US17139393
申请日：2020-12-31
申请人： Schweitzer Engineering Laboratories, Inc.
发明人： Ritwik Chowdhury , Matchyaraju Alla , Satish Samineni , Normann Fischer , Dale S. Finney
IPC分类号： H02H7/045 , H02H3/16 , G01R31/08 , H02H3/20 , H02H7/26
摘要： Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.

3. 发明授权

US10578653B2 Overexcitation protection for electric power system equipment 有权
公开(公告)号：US10578653B2
公开(公告)日：2020-03-03
申请号：US15910226
申请日：2018-03-02
申请人： Schweitzer Engineering Laboratories, Inc.
发明人： Ritwik Chowdhury , Dale S. Finney
IPC分类号： H02P9/00 , G01R19/165 , G01R19/25 , H02P9/10 , H02J3/44 , H02H7/045
摘要： Disclosed are systems and methods to determine an overexcitation condition on electric power delivery system equipment that includes a magnetizing core. Overexcitation conditions are determined even during sub-synchronous resonance, ferro-resonance, and other complex events. Power system voltage is integrated and normalized to determine a flux on the magnetizing core. The flux is compared with a protection model to determine the overexcitation condition on the magnetizing core. Once an overexcitation condition is detected, a protective action may be taken to remove power from the effected power delivery system equipment.

4. 发明申请

US20180261999A1 APPARATUS AND METHOD FOR DETECTING DISCONNECTION IN SECONDARY SIDE OF CURRENT TRANSFORMER 审中-公开
公开(公告)号：US20180261999A1
公开(公告)日：2018-09-13
申请号：US15462913
申请日：2017-03-20
申请人： NXP USA, INC.
发明人： CHANGHAO SHI , RUI LV , DECHANG WANG
IPC分类号： H02H7/04 , H02H3/20 , H02H7/045 , G01R31/02
CPC分类号： H02H7/042 , G01R31/027 , H02H3/20 , H02H7/045
摘要： An apparatus for detecting disconnection of a secondary side of a current transformer includes a sampling circuit coupled to the secondary side of the current transformer that samples signals from the secondary side of the current transformer. A pull-up circuit is switchably coupled to the sampling circuit in response to a coupling signal in a diagnostic phase. A processor is coupled to the sampling circuit for receiving sampled signals from the sampling circuit. The processor extracts corresponding signal information from the sampled signals and stores the extracted signal information in a memory. The extracted signal information corresponds to statuses that the secondary side of the current transformer is connected or disconnected to a load. A detector is coupled to the processor and the memory, and accesses the memory using the signal information of the sampled signals.

5. 发明授权

US09899830B2 Method for detecting fault and current differential protection system thereof 有权
公开(公告)号：US09899830B2
公开(公告)日：2018-02-20
申请号：US14770240
申请日：2013-04-07
申请人： ABB Schweiz AG
发明人： Youyi Li , Kai Liu , Ivo Brncic , Zhanpeng Shi
IPC分类号： H02H9/02 , H02H3/28 , H02H3/00 , H02H7/045
CPC分类号： H02H9/02 , H02H3/006 , H02H3/28 , H02H3/283 , H02H7/045
摘要： The present invention discloses a method for detecting a fault and a current differential protection system thereof. The method for detecting fault includes calculating fault component currents, calculating an operate current and a restraint current of all terminals, and adjusting an operate level by adapting an operate-restraint characteristic according to a fault component. The method has very small operating area for external faults, which makes the method very reliable even for the case with serious CT saturation. A very big operating area for internal faults makes the method very sensitive for internal faults even for a heavy load and high resistance fault.

6. 发明授权

US09891289B2 Power transformer inrush current detector 有权
公开(公告)号：US09891289B2
公开(公告)日：2018-02-13
申请号：US14727956
申请日：2015-06-02
申请人： Cooper Technologies Company
发明人： Ljubomir A. Kojovic
IPC分类号： G01R31/40 , G01R15/18 , G01R19/165 , G01R19/10 , H02H3/28 , H02H7/045
CPC分类号： G01R31/40 , G01R15/181 , G01R19/10 , G01R19/16504 , H02H3/28 , H02H7/045
摘要： Techniques for detecting an inrush current in a power transformer in are disclosed. For example, the presence of an inrush current on a current path in a power transformer may be determined by receiving a signal from a Rogowski coil positioned on a current path of a power transformer, the signal corresponding to a current flowing in the current path; sampling the received signal to produce samples of the received signal; and analyzing the samples of the received signal relative to at least two criteria to determine whether an inrush current is present. When an inrush current is present, operation of a protective relay is blocked.

7. 发明申请

US20170331279A1 Differential Protection Method And Differential Protection Device For Performing A Differential Protection Method 审中-公开
公开(公告)号：US20170331279A1
公开(公告)日：2017-11-16
申请号：US15526802
申请日：2014-11-14
申请人： SIEMENS AKTIENGESELSCHAFT
发明人： FRANK MIESKE
IPC分类号： H02H7/045 , H02H7/06 , H02H3/30 , G01R31/02 , H02J3/00 , G01R19/165
CPC分类号： H02H7/0455 , G01R19/165 , G01R31/025 , H02H3/30 , H02H7/045 , H02H7/065 , H02J3/00
摘要： A differential protection method for generating a fault signal includes measuring current measurements at least at two different measuring points of a multiphase transformer for each phase. The current measurements for each phase are used to form differential current values and stabilization values. The fault signal is generated if it is determined during a trigger region check that a measurement pair of at least one of the phases, being formed by using one of the differential current values and the associated stabilization value in each case, is in a predefined trigger region. In order to be able to selectively and reliably distinguish an external fault from an internal fault, the transformer has a grounded star point and a zero system current flowing through the star point is used to form the stabilization values. A corresponding differential protection device is provided for performing the differential protection method.

8. 发明授权

US09640981B2 Frequency-conversion differential protection method for output transformer of static frequency converter system 有权
公开(公告)号：US09640981B2
公开(公告)日：2017-05-02
申请号：US14426873
申请日：2013-07-01
申请人： NR ELECTRIC CO., LTD , NR ENGINEERING CO., LTD
发明人： Jun Chen , Quanrong Shen , Wei Yan , Huimin Wang , Kai Wang , Huazhong Li
IPC分类号： H02H7/04 , H02H7/045
CPC分类号： H02H7/045
摘要： A frequency-conversion differential protection method for an output transformer of a static frequency convertor system. The method comprises: a protection device measuring a three-phase current at each side of an output transformer of an SFC system; according to the connection manner of the output transformer, using a triangle side as a reference to conduct phase correction on a star side; at the same time, taking into account different secondary rated currents at each side of the transformer to adjust a balance coefficient of each side, so as to form sampling values of a correcting current and a differential current at each side, and using a startup and shut-down protection algorithm free from frequency influence in generator protection to calculate amplitude values of the correcting current, the differential current and a restraint current; and according to the magnitudes of the differential current and the restraint current, using the ratio restraint differential characteristic to achieve the frequency-conversion ratio differential protection of the output transformer. The present protection method is suitable for large-scale frequency change. Compared with the current quick-breaking protection, the sensitivity of internal failure detection in the output transformer is greatly improved.

9. 发明申请

US20170018919A1 PREVENTION METHOD OF ABNORMAL ACTION PROTECTION OF UHV REGULATING COMPENSATION TRANSFORMER WITH NO-LOAD INPUT 审中-公开
标题翻译：具有无负载输入的特高压调节补偿变压器的异常动作保护方法
公开(公告)号：US20170018919A1
公开(公告)日：2017-01-19
申请号：US15076664
申请日：2016-03-22
申请人： XJ GROUP CORPROATION , XJ ELECTRIC CO.,LTD , XUCHANG XJ SOFTWARE TECHNOLOGIES LTD , STATE GRID CORPORATION OF CHINA
发明人： Jirui Chen , Jiansong Zhao , Yun Gong , Maojun Deng , Chuankun Ni , Dongxiao Yao , Heke Ma , Lijuan Lv , Baowei Li , Xu Li , Jidong Huang , Feng Xiao , Shasha Hu , Jingli Zhang , Yingying Xi
IPC分类号： H02H7/045
CPC分类号： H02H7/045
摘要： The present invention relates to a prevention method of abnormal action protection of UHV regulating compensation transformer with no-load input, the prevention method includes: first determining a value of differential current of regulating compensation transformer, if the value of differential current is smaller than a pre-setting threshold, then, identifying whether an uninterruptible point of differential current waveform meets an pre-setting regulation according to original value of differential current or sampling value of differential difference current, and determining comprehensively whether the regulating compensation transformer is in no-load input or in fault directly with a value of second harmonic content of logic differential current together; if a value of differential current before pre-setting period is larger than the pre-setting threshold, the regulating compensation transformer is diagnosed to have external CT saturation, determining comprehensively whether the regulating compensation transformer is in no-load input or in fault by using result of the uninterruptible point after delaying and the value of second harmonic content of logic difference together, and corresponding inactivating or activating differential protection. By using the value of differential current before a pre-setting period, characteristics of the original value of differential current and the sampling value of differential difference current, and second harmonic inrush to discriminate an pre-setting regulation, the present invention can avoid the regulating compensation transformer occurring abnormal action when no-load switching transformer of UHV substation is charging, and isolating the fault quickly when the no-load switching transformer is in fault state.
摘要翻译：本发明涉及一种空载输入特高压调压补偿变压器异常动作保护的预防方法，其预防方法包括：首先确定调压补偿变压器的差动电流值，如果差动电流值小于预设阈值，然后根据差分电流的原始值或差分电流的采样值，确定差动电流波形的不间断点是否满足预设调节，并综合判断调节补偿变压器是否空载输入或故障直接与逻辑差分电流的二次谐波含量值一起; 如果预设周期之前的差分电流值大于预设阈值，则调节补偿变压器被诊断为具有外部CT饱和，全面确定调节补偿变压器是空载输入还是故障使用延迟后不间断点的结果和逻辑差异的二次谐波含量的值一起，以及相应的失活或激活差动保护。通过在预设周期之前使用差分电流的值，差分电流的原始值的特性和差分电流的采样值以及二次谐波涌入来区分预设调节，本发明可以避免调节特高压变电站空载开关变压器正在充电时，补偿变压器发生异常动作，空载开关变压器处于故障状态时快速隔离故障。

10. 发明授权

US09385525B2 Magnetizing inrush current suppression device 有权
标题翻译：励磁浪涌电流抑制装置
公开(公告)号：US09385525B2
公开(公告)日：2016-07-05
申请号：US14205090
申请日：2014-03-11
申请人： KABUSHIKI KAISHA TOSHIBA
发明人： Tadashi Koshizuka , Minoru Saito , Shiro Maruyama , Hiroyuki Maehara , Koji Suzuki
IPC分类号： H02H7/04 , H02H9/00 , H01H9/56 , H02H7/045 , H02H3/08 , H02H9/04 , H02H3/44
CPC分类号： H02H9/002 , H01H9/563 , H02H3/08 , H02H3/44 , H02H7/04 , H02H7/042 , H02H7/045 , H02H9/04
摘要： According to one embodiment, there is provided a magnetizing inrush current suppression device. A closing phase determination unit determines a phase position for suppressing the magnetizing inrush current among phase positions in which the prospective magnetic flux calculated by the prospective magnetic flux calculation unit and the residual magnetic flux calculated by the residual magnetic flux calculation unit coincide between the lines of the minimum residual magnetic flux determined by the minimum residual magnetic flux determination unit, as a closing phase position. A closing unit simultaneously closes the three phases of the circuit-breaker at the determined closing phase position.
摘要翻译：根据一个实施例，提供了一种励磁涌流抑制装置。关闭相位确定单元确定用于抑制由预期磁通计算单元计算出的预期磁通量和由剩余磁通计算单元计算出的剩余磁通量的相位位置之间的磁化冲击电流的相位位置，由最小剩余磁通量确定单元确定的最小剩余磁通量作为闭合相位置。闭合单元同时在确定的闭合相位置处闭合断路器的三相。

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