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1. 发明专利

JPH10322888A METHOD AND SYSTEM FOR LOCATING GROUND FAULT ON POWER LINE 失效
公开(公告)号：JPH10322888A
公开(公告)日：1998-12-04
申请号：JP12525997
申请日：1997-05-15
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , NAKAMURA MITSURU , YOKOYAMA HIROSHI , KUROSAWA AKIHIRO
IPC分类号： H02H3/40
摘要： PROBLEM TO BE SOLVED: To locate a ground fault on a power line quickly by calculating the distance to a ground fault point from a detecting means based on system constants for calculation when a decision is made that a detected electric waveform matches a calculated electric waveform. SOLUTION: A decision is made that a ground fault occurred on the distribution line of slave stations 10, 11 having phase inversion by locating the point on the distribution line where the phase of zero-phase current is inverted. Waveform of the zero-phase current is then calculated at the fixing point of a sensor 6 adjacent to the faulty section and the ground fault point, the ground fault resistance and various system constants are updated repeatedly until a decision is made that a measured waveform matches a calculated waveform. When a decision is made that the waveforms match each other, the distance to the ground fault point is calculated from the line reactance and the distance from the fixing point of the sensor 6 to the ground fault point is outputted to a display section. According to the arrangement, ground fault can be located surely using a relatively small number of sensors regardless of variation in the system configuration or the ground fault resistance.

2. 发明专利

JPH0787662A METHOD AND SYSTEM FOR DETECTION AND TREATMENT OF LINE-TO-GROUND FAULT OF POWER SYSTEM 失效
公开(公告)号：JPH0787662A
公开(公告)日：1995-03-31
申请号：JP23210193
申请日：1993-09-20
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , NISHIJIMA KAZUO , YONEYAMA TSUKASA , AKUTSU GIICHI
IPC分类号： H02H3/34 , H02H3/44
摘要： PURPOSE:To prevent the malfunction of a system due to the change of grounding currents, zero phase voltage or zero phase currents by successively storing power information in a master station, comparing zero phase voltage and zero phase currents and reference values and deciding whether or not a ground fault is true. CONSTITUTION:A sensor device 12 is composed of a grounding transformer, in which a primary winding is connected to a three-phase bus 4, and each phase voltage is detected from the seconday winding of the grounding transformer and zero phase voltage from the tertiary winding of the grounding transformer, and input to a seven channel amplifier 22. Zero phase voltage is also input to a comparator 24. Zero phase currents in the root of each feeder are input to the seven channel amplifier 22 by sensor devices 7 mounted on each feeder, and output to a memory 26. When the change width of zero phase voltage reaches a reference signal or more in the comparator 24, the time data of each phase voltage, zero phase voltage and zero phase currents are held to the memory 26, and whether or not the change of zero phase voltage is generated by a true ground fault or the on-off of load is decided by a ground-fault generating decision section 27.

3. 发明专利

JPH041579A DETECTION OF INSULATION DETERIORATION OF ELECTRIC POWER SYSTEM 失效
公开(公告)号：JPH041579A
公开(公告)日：1992-01-07
申请号：JP10202490
申请日：1990-04-18
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , WAKE SHOJI , TORII HISANOBU
IPC分类号： G01R31/02 , H02H3/17
摘要： PURPOSE:To reduce an insulation deterioration and the effects of its residual amount in the section and of a noise, and to detect them with high sensitivity by injecting a voltage signal into a 3-phase bus line and calculating electrostatic capacitances to the ground for each phase from the detected values in terms of injection frequencies of a zero-phase-sequence current and voltages for each phase. CONSTITUTION:Sine waves having three phases and three kinds of frequency components are oscillated from oscillators 23R, 23S, 23T shown in the figure. These signals are continuously injected through insulation transformers 22R, 22S, 22T and high voltage coupling capacitors 21R, 21S, 21T. For three kinds of frequency components at this time, the frequencies other than the power source frequency and its harmonic frequencies are selected to distinguish the signal for harmonic frequencies of the power source frequency. The amount of injection voltage is selected to the almost equal values for all three phases within the range unaffecting the system. As the result of abovementioned voltage injection, the zero-phase-sequence current and voltages for each phase in terms of the injection frequencies can be detected at each point along a distribution line.

4. 发明专利

JPH04368416A METHOD AND DEVICE FOR DETECTING INSULATION DETERIORATION OF POWER SYSTEM 失效
公开(公告)号：JPH04368416A
公开(公告)日：1992-12-21
申请号：JP14461691
申请日：1991-06-17
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , HIRASAWA KUNIO , HAGA HIROSHI , TORII HISANOBU
IPC分类号： G01R31/12 , H02H1/00 , H02H3/00 , H02H7/26
摘要： PURPOSE:To reduce the influence of a residual component and impulsive noise so as to highly sensibly detect the insulation deterioration of a power system by using a phase difference spectrum between a zero-phase voltage in a band from which the integer-multiple frequency of a power supply frequency is removed and a zero-phase current. CONSTITUTION:A zero-phase voltage detecting block 20 detects the zero-phase voltage of a power transmission line at a detecting point and a zero-phase current detecting block detects a zero-phase current. Unnecessary frequency component removing blocks 23A and 23B remove power supply frequency components and their integer-multiple frequency components from the detected zero-phase voltage and current. The zero-phase voltage and current from which the unnecessary frequency component is removed are converted into a phase-difference spectrum by means of a phase-difference spectrum comparing block 31. Then a phase-difference comparing block 31 compares the phase-difference spectrum with another phase-difference spectrum similarly converted on the basis of the zero-phase voltage and current at another detecting point. A deterioration discriminating block 32 discriminates deterioration based on the compared result of the block 31. Therefore, insulation deterioration can be detected with high sensitivity by reducing the influence of a residual component and impulsive noise.

5. 发明专利

JPH04368415A METHOD OF DETECTING INSULATION DETERIORATION OF POWER SYSTEM AND DEVICES FOR DETECTING, DISCRIMINATING, AND MONITORING INSULATION DETERIORATION, GROUNDING GENERATOR, AND RESONANCE FREQUENCY MEASURING SYSTEM 失效
公开(公告)号：JPH04368415A
公开(公告)日：1992-12-21
申请号：JP14451691
申请日：1991-06-17
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , HIRASAWA KUNIO , HAGA HIROSHI , AOYANAGI MITSUHIRO , ITO KAZUMI
IPC分类号： G01R31/02 , G01R29/16 , G01R31/12 , H02H3/00 , H02H7/26
摘要： PURPOSE:To reduce the influence of a residual component, noise, etc., so as to detect the insulation deterioration of a three-phase power system with high sensitivity by detecting zero-phase voltages in bands except the resonance frequency of the power system. CONSTITUTION:A sensor device 20 is constituted of a V0 sensor using a grounding transformer composed of a star-connected primary winding 22 connected to a three-phase bus 3 and delta- connected secondary winding 23 and a slave station 21 is connected to a host station through a communication line 33. The voltage V0 detected across both ends of a current-limiting resistance 24 is inputted to an amplifier 25 by which the voltage is converted into a voltage signal which is suitable for signal processing. A V0 signal generated when deterioration occurs contains many frequency components other than a power supply frequency and frequencies of the natural-number multiple of the frequency and, the frequency components become larger as their frequencies become lower. Therefore, when the power supply frequency component which contains the largest amount of a residual component is eliminated from the output signal of the amplifier 24 by means of a 5-Hz notch filter 26 and system noise is removed by means of a 1kHz low-pass filter 27, only the small V0 signal which becomes relatively large when deterioration occurs can be extracted with high accuracy.

6. 发明专利

JPH02111217A TROUBLE PRECOGNITION SYSTEM FOR POWER SYSTEM 失效
公开(公告)号：JPH02111217A
公开(公告)日：1990-04-24
申请号：JP26336288
申请日：1988-10-19
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , HIGAKI MASARU , HAGA HIROSHI , AKISAWA YASURO , YAMASHITA TAKAHIRO , OGAWA TORU
IPC分类号： G01R31/08 , H02H3/00 , H02H3/52
摘要： PURPOSE:To reduce insulation deterioration in a power system and influence of noise to the detection of its zone and to detect with high sensitivity by dividing the system into a plurality of zones, providing zero-phase current sensors in the boundaries of the zones, and determining the insulation deterioration of the zero on the basis of its general evaluation. CONSTITUTION:When insulation deterioration occurs in a feeder II, ground charging currents IC1, IC3 of hot-line feeders I, III flow to a deterioration point F through a feeder 3. A current IN also flows to the point F through an equivalent resistor 21. On the other hand, charging currents IC2' and IC2'' also flow reversibly through the point F via the feeder II itself. As a result, zero-phase currents detected by the zero-phase current sensors of II-b and II-c become reverse phase, and the currents except the former become in phase. Accordingly, the presence of the deterioration point in the zone interposed between the zero- phase current sensors having the reverse phase can be detected.

7. 发明专利

JPH05122829A METHOD AND DEVICE FOR DETECTING DETERIORATION OF INSULATION IN POWER SYSTEM 失效
公开(公告)号：JPH05122829A
公开(公告)日：1993-05-18
申请号：JP27536691
申请日：1991-10-23
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , NAGAYAMA KATSUYA , AOYANAGI MITSUHIRO
IPC分类号： G01R31/02 , G06F15/18 , G06N3/00 , G06N99/00 , H02H3/00 , H02H3/347 , H02H3/38 , H02H7/26
摘要： PURPOSE:To eliminated the influence of noise signal or residual component such as zero-phase voltage by a constitution wherein a neural network model learns the correlation between a frequency spectral pattern and a deteriorated state of system insulation as a teacher signal in order to detect system deterioration based on the output signals therefrom. CONSTITUTION:A neural network model 100 determines a weight relation represented by couplings 135 between neuron element models 134. When a frequency spectral pattern of zero-phase voltage, obtained at site, is inputted to an input layer 131, calculation results Z are outputted to a neuron element model 134 in an output layer 133 based on the weight relation obtained through learning. The neuron element model 134 is set such that the calculation results Z have a value between 0 and 1. Possibility of deterioration of insulation becomes higher as Z approaches from 0 to 1. When Z exceeds a level alpha, a decision routine 138 makes a decision of degradation of insulation and holding signals are delivered from a master station 14 to slave stations 15A-17B.

8. 发明专利

JPH0342584A DECIDING SYSTEM FOR INSULATION DETERIORATION OF ELECTRIC POWER SYSTEM 失效
公开(公告)号：JPH0342584A
公开(公告)日：1991-02-22
申请号：JP17782889
申请日：1989-07-10
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KANAI MINORU , IWASHITA KIYOJI , HIGAKI MASARU , HAGA HIROSHI , DOBASHI HACHIRO , YAMASHITA TAKAHIRO , TORII HISANOBU
IPC分类号： G01R31/12 , G01R31/08 , H02H3/28
摘要： PURPOSE:To detect an insulation deterioration of electric power system with high sensitivity by obtaining admittances against ground of each phase in a section to be monitored and deciding the insulation deterioration of power system in the section to be monitored in accordance with these calculated values. CONSTITUTION:At first, outputs of zero-phase-sequence current sensors 15a, 16a, 17a are fetched and time system data for the zero-phase-sequence currents I0 at the output side of an electricity distributing and transforming station 1 are fetched to a computer 11, and amounts and directions of the current I0 of each feeder 12, 13, 14 are compared to decide whether the directions of currents I0 are different from a normal value and also the amounts are increased beyond a set level or not. When the detected values of current I0 do not exceed the set value, the process is continued, and if they exceed, held signals are outputted through each communication terminal 27, then the contents of memories 26 in each section are held and transferred to the computer 11 through the terminals 27 and a communication circuit 28. By the computer 11, a spectrum analysis for frequency is made for the transferred time series data to perform a processing to obtain the absolute values and the phases for every frequency. The processing for obtaining insulation resistances against ground and electrostatic capacitances against ground are performed in accordance with the above results.

9. 发明专利

JPS6174222A Vacuum breaker 失效
公开(公告)号：JPS6174222A
公开(公告)日：1986-04-16
申请号：JP19473384
申请日：1984-09-19
申请人： Hitachi Ltd
发明人： KUROSAWA YUKIO , IWASHITA KIYOJI , MATSUMOTO MORIHISA , WATANABE RYUJI
IPC分类号： H01H33/66 , H01H1/02
CPC分类号： H01H1/0203

10. 发明专利

JPS585929A ELECTRODE FOR VACUUM BREAKER 失效
公开(公告)号：JPS585929A
公开(公告)日：1983-01-13
申请号：JP10341081
申请日：1981-07-03
申请人： HITACHI LTD
发明人： IWASHITA KIYOJI , KUROSAWA YUKIO , WADA AKIRA
IPC分类号： H01H33/66

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