公开(公告)号：US06397156B1

公开(公告)日：2002-05-28

申请号：US09192851

申请日：1998-11-17

申请人： Bernhard Bachmann ,  David G. Hart ,  Yi Hu ,  Damir Novosel ,  Murari M. Saha

发明人： Bernhard Bachmann ,  David G. Hart ,  Yi Hu ,  Damir Novosel ,  Murari M. Saha

IPC分类号： G01R2500

CPC分类号： H02H3/40 ,  H02H1/04

摘要： An accurate impedance measurement method for a power system transmission line is disclosed for improving various protection functions, i.e., distance protection and/or fault location estimation. The method is less sensitive to harmonics and other transient problems introduced to power systems by series capacitance and the like, and is easily incorporated into existing protective relays. In the method, a number (n) of current and voltage samples (Ik, Vk) representative of values of current and voltage waveforms are measured, respectively, at successive instants of time on a conductor in a power system. The number n is an integer greater than I and the index k takes on values of 1 to n. Resistance (R) and inductance (L) values are computed in accordance with an equation in which R and L are related to sums of differences in values of successive current and voltage samples. A prescribed power system function is then performed based on the computed R and L values.

摘要翻译： 公开了一种用于电力系统传输线路的精确阻抗测量方法，用于改进各种保护功能，即距离保护和/或故障位置估计。 该方法对通过串联电容等引入电力系统的谐波和其他瞬态问题较不敏感，并且容易地并入现有的保护继电器中。 在该方法中，分别在电力系统中的导体上的连续时刻分别测量表示电流和电压波形值的电流和电压样本数（Ik，Vk）的数量（n）。 数字n是大于I的整数，索引k取值为1到n。 电阻（R）和电感（L）值根据其中R和L与连续电流和电压样本的值的差的和相关的方程式来计算。 然后根据计算的R和L值执行规定的电力系统功能。

公开(公告)号：US06336059B1

公开(公告)日：2002-01-01

申请号：US09192956

申请日：1998-11-17

申请人： Damir Novosel ,  Bernhard Bachmann ,  Yi Hu ,  David G. Hart ,  Murari M. Saha

发明人： Damir Novosel ,  Bernhard Bachmann ,  Yi Hu ,  David G. Hart ,  Murari M. Saha

IPC分类号： G05B1900

CPC分类号： H02H3/40

摘要： A reach-measurement method is used in connection with a series-compensated line of a power system. The series-compensated line includes an installed series capacitance having a bus side and a line side, and a non-linear protection device parallel to the installed series capacitance. The series-compensated line has a line current, a bus side voltage, and a line side voltage. The series capacitance and the non-linear protection device have a capacitance voltage thereacross equal to the bus side voltage minus the line side voltage. In the method, a number (n) of line current samples are measured, where such samples are representative of values of a line current waveform at successive instants of time on the series-compensated line. Capacitance voltage values are computed based on the measured line current samples in accordance with an equation which takes into account the non-linear protection device parallel to the installed series capacitance. A prescribed power system function is then performed based on the computed capacitance voltage values.

摘要翻译： 与电力系统的串联补偿线结合使用到达测量方法。 串联补偿线包括具有总线侧和线路侧的安装的串联电容以及与安装的串联电容并联的非线性保护装置。 串联补偿线路具有线路电流，总线侧电压和线路侧电压。 串联电容和非线性保护装置的电容电压与母线侧电压减去线路侧电压相等。 在该方法中，测量线数电流样本数（n），其中这些采样代表串联补偿线上连续时刻的线电流波形的值。 电容电压值是根据测得的线路电流样本根据考虑到与安装的串联电容平行的非线性保护装置的方程计算的。 然后基于计算的电容电压值执行规定的电力系统功能。

公开(公告)号：US06584417B1

公开(公告)日：2003-06-24

申请号：US09425661

申请日：1999-10-22

申请人： Yi Hu ,  Damir Novosel ,  David G. Hart

发明人： Yi Hu ,  Damir Novosel ,  David G. Hart

IPC分类号： G01R3108

CPC分类号： G01R31/085 ,  H02H3/081 ,  H02H3/405

摘要： An electrical power system includes a transmission line for transmitting electrical power, series capacitance compensation series-coupled to the transmission line adjacent one end thereof, where the series compensation includes a capacitance having a value (−j XCAP), and a protective relay at the one end of the transmission line for monitoring line voltages and line currents on the transmission line. Upon sensing a fault, an impedance Z of the line is calculated based on the monitored line voltages and line currents. The calculated impedance Z is adjusted according to the value of the capacitance of the series compensation (−j XCAP) to result in a modified impedance ZMOD, and the phasor angle Of ZMOD is examined to determine the direction of the sensed fault. The fault is in a first direction if the phasor angle is between X and X+180 degrees and is in a second direction opposite the first direction if the phasor angle is between X+180 and X+360 degrees.

摘要翻译： 电力系统包括用于发送电力的传输线，串联耦合到其一端附近的传输线的串联电容补偿，其中串联补偿包括具有值（-j XCAP）的电容，以及保护继电器 传输线的一端用于监测传输线上的线路电压和线路电流。 在检测到故障时，根据被监测的线路电压和线路电流计算线路的阻抗Z。 根据串联补偿（-j XCAP）的电容值调整计算阻抗Z，得到修正的阻抗ZMOD，并检查ZMOD的相量角以确定感测故障的方向。 如果相量角在X和X + 180度之间，并且如果相量角在X + 180和X + 360度之间，并且处于与第一方向相反的第二方向，则故障处于第一方向。

公开(公告)号：US06453248B1

公开(公告)日：2002-09-17

申请号：US09119792

申请日：1998-07-21

申请人： David G. Hart ,  Damir Novosel ,  Steven A. Kunsman

发明人： David G. Hart ,  Damir Novosel ,  Steven A. Kunsman

IPC分类号： G01R3100

CPC分类号： G01R31/088 ,  G01R31/085 ,  G01R31/086 ,  H02H1/0015 ,  Y04S10/522

摘要： An improved high impedance fault (HIF) detection system comprises an analyzer located at a circuit breaker or substation with feeders, wherein the analyzer analyzes current and/or voltage waveforms to detect a HIF on the feeder or on one of a plurality of laterals coupled to the feeder; a plurality of remote outage detectors located respectively at corresponding customer sites, each remote outage detector including a mechanism to detect a loss of potential or power at the corresponding site; and a computer in communication with the analyzer and the remote outage detectors.

摘要翻译： 改进的高阻抗故障（HIF）检测系统包括位于具有馈线的断路器或变电站的分析仪，其中分析器分析电流和/或电压波形，以检测馈线上的HIF或多个耦合到 进料器; 分别位于相应的客户位置的多个远程停机检测器，每个远程停电检测器包括用于检测对应站点的电位或电力损失的机构; 以及与分析仪和远程停机检测器通信的计算机。

公开(公告)号：US5832414A

公开(公告)日：1998-11-03

申请号：US939932

申请日：1997-09-29

申请人： David G. Hart ,  James D. Stoupis ,  Damir Novosel

发明人： David G. Hart ,  James D. Stoupis ,  Damir Novosel

IPC分类号： G01R19/25 ,  G01R23/00 ,  G01R23/16 ,  G01R23/10

CPC分类号： G01R19/2513 ,  G01R23/16 ,  G01R23/00

摘要： A new method of compensating for errors in phasor estimation due to oscillations caused by discrete fourier transforms used to estimate signal frequency is provided. The method uses a variable N-point DFT to compute one or more phasors based on data acquired from one or more sampled signals. At each sampling interval the change in phasor angle between the current sampling interval and the previous sampling interval is determined and used to estimate the instantaneous frequency of the signal. A non-oscillating phasor indicative of the instantaneous magnitude, angular frequency, and phase angle of the signal is generated based on the instantaneous frequency estimate. Instantaneous frequencies are averaged over a cycle of the signal to generate an average cycle frequency. In addition, a number of discrete frequencies and corresponding DFT windows based on a fixed sampling rate and a predetermined fundamental frequency of the signal are defined and used in estimating the instantaneous frequency. The DFT window is adjusted by setting it equal to the DFT window corresponding to the discrete frequency closest to the average cycle frequency. A generator protection system analyzing voltage and current signals output from a generator is also provided. The voltage and current signals are monitored by respective voltage and current sensors to produce a plurality of signals representative of voltage and current characteristics of the generator. The system comprises components for receiving and sampling signal input, and for processing the samples according to the inventive method.

摘要翻译： 提供了一种补偿由于用于估计信号频率的离散傅立叶变换引起的振荡引起的相量估计误差的新方法。 该方法使用可变N点DFT来基于从一个或多个采样信号获取的数据来计算一个或多个相量。 在每个采样间隔，确定当前采样间隔和先前采样间隔之间的相量角的变化，并用于估计信号的瞬时频率。 基于瞬时频率估计产生指示信号的瞬时幅度，角频率和相位角的非振荡相量。 瞬时频率在信号的周期上平均以产生平均周期频率。 另外，基于固定采样率和信号的预定基频定义了多个离散频率和相应的DFT窗口，并用于估计瞬时频率。 通过将DFT窗口设置为与最接近平均周期频率的离散频率对应的DFT窗口进行调整。 还提供了分析从发电机输出的电压和电流信号的发电机保护系统。 电压和电流信号由相应的电压和电流传感器监测，以产生代表发电机的电压和电流特性的多个信号。 该系统包括用于接收和采样信号输入的组件，并且用于根据本发明的方法处理样本。

公开(公告)号：US06173216B2

公开(公告)日：2001-01-09

申请号：US09060508

申请日：1998-04-15

申请人： Khoi Vu ,  David G. Hart ,  Damir Novosel

发明人： Khoi Vu ,  David G. Hart ,  Damir Novosel

IPC分类号： H02J114

CPC分类号： H02H1/0092 ,  G01R19/2513

摘要： As a variation of the non-orthogonal filter, a phasor estimate is computed by using an N-point window. An aspect of the sub-window cosine filter is to repeat the basic cosine filter for only selected points of the window. In the end, a least-squares fit is used to obtain an estimate for the phasors components. Previous cosine techniques use a data window whose length is greater than 1 cycle while the present invention requires only 1 cycle.

摘要翻译： 作为非正交滤波器的变型，通过使用N点窗口来计算相量估计。 子窗口余弦滤波器的一个方面是仅对窗口的选定点重复基本余弦滤波器。 最后，使用最小二乘拟合来获得相量分量的估计。 以前的余弦技术使用长度大于1周期的数据窗口，而本发明仅需要1个周期。

公开(公告)号：US6154687A

公开(公告)日：2000-11-28

申请号：US60458

申请日：1998-04-15

申请人： David G. Hart ,  Damir Novosel ,  Robert A. Smith

发明人： David G. Hart ,  Damir Novosel ,  Robert A. Smith

IPC分类号： G01R19/25 ,  H02H3/38 ,  H02J1/14 ,  H02H7/00 ,  H02H9/00 ,  H02J3/02 ,  H02J17/00

CPC分类号： G01R19/2513 ,  H02H3/38

摘要： A high sample rate cosine filter eliminates DC components by summing them such that they sum to zero. A non-orthogonal cosine filter is also provided. When the cosine filter is applied for N=4 samples per cycle, the samples are separated by 90 degrees. However, at higher sampling rates, it is not necessary to wait for 90 degrees to estimate the phasor value. Non-orthogonal components are used to estimate the phasor value. The time delay associated with the cosine filter is reduced in the process.

摘要翻译： 高采样率余弦滤波器通过将它们相加来消除DC分量，使得它们总和为零。 还提供了非正交余弦滤波器。 当每个循环使用余弦滤波器N = 4个样本时，样本被分离90度。 然而，在更高的采样率下，不需要等待90度来估计相量值。 非正交分量用于估计相量值。 与余弦滤波器相关的时间延迟在该过程中减少。

公开(公告)号：US5839093A

公开(公告)日：1998-11-17

申请号：US777623

申请日：1996-12-31

申请人： Damir Novosel ,  David Hart ,  Yi Hu ,  Jorma Myllymaki

发明人： Damir Novosel ,  David Hart ,  Yi Hu ,  Jorma Myllymaki

IPC分类号： G01R31/08 ,  H02H3/26

CPC分类号： G01R31/086

摘要： Both fault location and fault resistance of a fault are calculated by the present method and system. The method and system takes into account the effects of fault resistance and load flow, thereby calculating fault resistance by taking into consideration the current flowing through the distribution network as well as the effect of fault impedance. A direct method calculates fault location and fault resistance directly while an iterative fashion method utilizes simpler calculations in an iterative fashion which first assumes that the phase angle of the current distribution factor D.sub.s is zero, calculates an estimate of fault location utilizing this assumption, and then iteratively calculates a new value of the phase angle .beta..sub.s of the current distribution factor D.sub.s and fault location m until a sufficiently accurate determination of fault location is ascertained. Fault resistance is then calculated based upon the calculated fault location. The techniques are equally applicable to a three-phase system once fault type is identified.

摘要翻译： 通过本方法和系统计算故障位置和故障故障电阻。 该方法和系统考虑了故障电阻和负载流量的影响，从而通过考虑流经配电网络的电流以及故障阻抗的影响来计算故障电阻。 直接方法直接计算故障位置和故障电阻，而迭代方法以迭代方式利用更简单的计算，首先假设电流分布因子Ds的相位角为零，使用该假设计算故障位置的估计，然后 迭代地计算当前分布因子Ds和故障位置m的相位角βs的新值，直到确定故障位置的足够精确的确定。 然后根据计算出的故障位置计算故障电阻。 一旦发现故障类型，这些技术同样适用于三相系统。

公开(公告)号：US5671112A

公开(公告)日：1997-09-23

申请号：US647589

申请日：1996-05-13

申请人： Yi Hu ,  David Hart ,  Damir Novosel ,  Robert Smith

发明人： Yi Hu ,  David Hart ,  Damir Novosel ,  Robert Smith

IPC分类号： G01R19/04 ,  H02H7/04 ,  H02H3/18

CPC分类号： H02H7/04 ,  G01R19/04

摘要： A system for implementing accurate V/Hz value measurement and trip time determination for generator/transformer overexcitation protection independent of the conventional frequency tracking and phasor estimation based on Discrete Fourier Transformation (DFT) techniques. A sampled sinusoidal voltage signal is passed through a digital integrator and the magnitude of the digital integrator's output is measured as representative of the V/Hz ratio. The digital integrator is implemented in software using a difference equation in a generator protection unit. The technique may be used with either a fixed or a variable sampling frequency. When the sampling frequency is variable, the filter coefficients of the digital integrator are recalculated on-line each time the sampling frequency is changed, and a new value for the peak magnitude of the output of the digital integrator is calculated using the recalculated filter coefficients. Non-linear frequency response characteristics of the voltage sensors and non-ideal characteristics of the digital integrator are also adjusted using the measured frequency and error-frequency characteristics of the particular digital integrator and voltage sensors used.

摘要翻译： 一种用于实现发电机/变压器过励磁保护的精确V / Hz值测量和跳闸时间确定的系统，与传统的基于离散傅里叶变换（DFT）技术的频率跟踪和相量估计无关。 采样的正弦电压信号通过数字积分器，并且数字积分器的输出的幅度被测量为代表V / Hz比。 数字积分器采用发电机保护单元中的差分方程软件实现。 该技术可以与固定或可变采样频率一起使用。 当采样频率可变时，每次采样频率改变时，数字积分器的滤波器系数在线重新计算，并且使用重新计算的滤波器系数计算数字积分器的输出的峰值幅度的新值。 电压传感器的非线性频率响应特性和数字积分器的非理想特性也使用所使用的特定数字积分器和电压传感器的测量频率和误差频率特性进行调整。

公开(公告)号：US5956220A

公开(公告)日：1999-09-21

申请号：US19321

申请日：1998-02-05

申请人： Damir Novosel ,  Yi Hu ,  Murari M. Saha

发明人： Damir Novosel ,  Yi Hu ,  Murari M. Saha

IPC分类号： H02H3/40 ,  H02H7/26 ,  H02H3/00

CPC分类号： H02H7/267 ,  H02H3/40

摘要： An adaptive distance relaying system provides improved performance for parallel circuit distance protection. The system utilizes the parallel circuit's current, when available, in conjunction with measurements of voltage and current on the protected line to compensate for the zero sequence current mutual coupling effect. The sequence current ratio (zero or negative sequence) is used to avoid incorrect compensation for relays on the healthy circuit. If the parallel circuit current is not available and the line operating status is, the best zero sequence current compensation factors are selected accordingly as a next level adaptation. If both the parallel circuit current and line operating status are unavailable, a fallback scheme that offers better results than classical distance protection schemes is employed.

摘要翻译： 自适应距离中继系统为并联电路距离保护提供了改进的性能。 该系统在可用时利用并联电路的电流与受保护线路上的电压和电流的测量结合，以补偿零序电流互耦效应。 顺序电流比（零或负序）用于避免健康电路上继电器的不正确补偿。 如果并联电路电流不可用并且线路运行状态是，则最佳的零序电流补偿因子被相应地选择为下一级适配。 如果并联电路电流和线路运行状态都不可用，则采用比传统距离保护方案更好的结果的回退方案。