Title:
METHOD FOR DETECTING FAILURE OF ELEMENT IN OPEN DELTA CONNECTION OF POWER CAPACITOR
Document Type and Number:
Japanese Patent JP3414608
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a method for detecting failure of capacitor element from the variation of open end voltage when a discharge coil is connected in parallel with a capacitor provided for each phase R, S, T and the secondary windings thereof are connected in open delta in which single element failure can be detected.
SOLUTION: With reference to a voltage related to at least two phases, e.g. a positive phase voltage (vector) V1, an open end voltage Vz and the phase difference θ1 from V1 are measured previously under sound state and E0 determined according to an expression Vz.exp(θ1).117.0/&verbar V1&verbar is stored, as an initial unbalance voltage, in a nonvolatile memory 16. Subsequently, the absolute value &verbar E1&verbar of vector fluctuation E1 with respect to E0 is determined from an actually measured open end voltage Vz', positive phase voltage V1' and phase difference θ2 according to an expression &verbar Vz'.exp(θ2).117.0/(&verbar V1'&verbar )-E0&verbar and compared with a set value thus determining element failure. Since E0 is canceled, voltage fluctuation due to element failure can be extracted accurately.
Inventors:
Takafumi Maeda
Mitsunori Nakamura
Junji Nagao
Masatoshi Noro
Kosaku Uemura
Mitsunori Nakamura
Junji Nagao
Masatoshi Noro
Kosaku Uemura
Application Number:
JP2552597A
Publication Date:
June 09, 2003
Filing Date:
February 07, 1997
Export Citation:
Assignee:
THE TOKYO ELECTRIC POWER COMPANY,INCORPORATED
Takatake Manufacturing Co., Ltd.
Nissin Electric Co., Ltd.
Takatake Manufacturing Co., Ltd.
Nissin Electric Co., Ltd.
International Classes:
H02H3/28; G05F1/70; H02H7/00; H02H7/16; (IPC1-7): H02H7/16; G05F1/70
Domestic Patent References:
| JP638692B2 | ||||
| JP4113540B1 |
Attorney, Agent or Firm:
Kenzo Hara