Electrical power distribution monitoring system and method

• US 6,061,609 A
• Filed: 08/05/1999
• Issued: 05/09/2000
• Est. Priority Date: 03/18/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nishijima, Kazuo, Takei, Toru, Yasukawa, Saburou, Imamura, Yuzuru, Iwashita, Kiyoji, Inoue, Hiroshi, Kudo, Hiroyuki, Kawakami, Junzo, Kanoi, Minoru
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): Nguyen, Cuong H.
• Application Number:
  US09/369,155
• Time in Patent Office: 278 Days
• Field of Search: 700/291, 700/286, 702/58-61, 702/63-65, 702/66, 340/825.06, 340/870.03, 340/870.02
• US Class Current: 700/291
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/04 for connecting networks of the same frequency but supplied from different sources
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge

Abstract

An electrical power distribution monitoring system is provided for a power distribution line having a plurality of sections with a plurality of electrical loads connected to the power distribution line to form a power distribution network. The monitoring system has at least one sensor for at least one present electrical value at least one point of the network, and estimates electrical values for at least one section of the line in dependence on both of present electrical values measured by the sensor and data relating to past power consumption by loads connected to the line. Improved prediction of actual conditions in the distribution line can be obtained.

Claims

1. An electrical power distribution monitoring system, for a power distribution line having a plurality of sections with a plurality of electrical loads connected to the power distribution line to form a power distribution network and having a power input at an input end, there being a plurality of electrical loads connected to the power distribution line to form a power distribution network, said monitoring system comprising:

(a) at least one first power sensor means arranged to measure power being supplied to said power distribution line at said input end;

(b) at least one second power sensor means arranged to measure power passing between said power distribution line and at least one specific one of said electrical loads;

(c) a data store containing data relating to past power consumption of said plurality of sections set in advance by electrical loads connected to said power distribution line;

(d) calculating means arranged to estimate electrical values for at least one said section of said power distribution line in dependence on present electrical values measured by said first power sensor and said second power sensor and said data in said data store; and

(e) distribution lines between said at least one first power sensor means and said calculating means, or between said at least one second power sensor means and said calculating means, used as a medium of a control signal.

2. An electrical power distribution monitoring system according to claim 1, wherein said at least one first power sensor means measures total power being supplied to said power distribution line.

3. An electrical power distribution monitoring system according to claim 1, wherein said at least one second power sensor means comprises a power sensor device arranged to measure power passing in a branch of said power distribution network connecting said at least one specific electrical load to said power distribution line.

4. An electrical power distribution monitoring system according to claim 1, wherein said at least one second power sensor means comprises two power sensor devices arranged to measure power passing in said power distribution line at respective points in said power distribution line, between which said at least one specific electrical load is connected to said power distribution line, thereby to provide a measurement of power passing between said power distribution line and said at least one specific electrical load.

5. An electrical power distribution monitoring system according to claim 1, wherein said at least one specific load, on average, consumes at least 5% of the total consumption by all of the electrical loads connected to said power distribution line.

6. An electrical power distribution monitoring system according to claim 1, wherein said calculating means is arranged to use data from said data store for predicting consumption by all of the electrical loads connected to said power distribution line except said at least one specific electrical load.

7. An electrical power distribution monitoring system according to claim 1, wherein said electrical loads comprise a plurality of electricity-consuming buildings.

8. An electrical power distribution monitoring system according to claim 1, wherein said calculating means calculates the difference of said at least one first power sensor means and said at least one second power sensor means, and calculates power consumption of every one of said sections by distributing calculated electrical power data.

9. An electrical power distribution monitoring system according to claim 1, wherein said at least one second power sensor means includes a power sensor arranged to measure power passing in a branch of said network connecting said specific load to said power distribution line.

10. An electrical power distribution monitoring system according to claim 1, wherein said calculating means is arranged to calculate estimated power values in each of a plurality of said sections of said power distribution line.

11. An electrical power distribution monitoring system according to claim 1, wherein said data in said data store comprises, as said data relating to past power consumption, data relating to past power consumption of each of said sections of said power distribution line.

12. An electrical power distribution monitoring system according to claim 1, wherein said calculating means is arranged further to calculate, from sections, the degree of deviation of said estimated electrical values from a predetermined standard value or values.

13. An electrical power distribution monitoring system, for a power distribution line having a plurality of sections and having a power input at an input end, there being a plurality of electrical loads connected to the power distribution line, said monitoring system comprising:

(a) measurement means for measuring an electrical value at least one of (i) a point on said power distribution, (ii) a selected one of said electrical loads, and (iii) a selected group of said electrical loads,

(b) a data store containing data relating to past power consumption by electrical loads connected to said power distribution line,

(c) calculating means connected to said measurement means and to said data store and arranged to calculate estimated electrical values in at least one of said sections of said power distribution line from both of at least one currently measured electrical value obtained by said measurement means and said data in said data store;

wherein said measurement means comprises at least a first measurement device for measuring said at least one currently measured electrical value in a portion of said power distribution line closer to said input end thereof than all of said electrical loads, and

distribution lines used as a medium of a control signal between said measurement means and said data store, or between said measurement means and said calculating means.

14. An electrical power distribution monitoring system according to claim 13, wherein said measurement means further comprises a second measurement device arranged to measure, as said at least one currently measured electrical value, at least the current passing between said power distribution line and said selected one of said electrical loads.

15. An electrical power distribution monitoring system according to claim 13, wherein said measurement means further comprises a plurality of second measurement devices arranged in said power distribution line to measure, as said at least one currently measured electrical value, at least the current passing between said power distribution line and said selected one or selected group of said electrical loads.

16. An electrical power distribution monitoring system according to claim 13, wherein said selected one of said electrical loads, on average, consumes at least 5% of total power consumption by all of the electrical loads connected to said power distribution line.

17. An electrical power distribution monitoring system according to claim 13, wherein said calculating means is arranged to calculate estimated power values in each of plural ones of said plurality of sections of said power distribution line.

18. An electrical power distribution monitoring system according to claim 13, wherein said data store contains, as said data relating to past power consumption, data relating to past power consumption of each said sections of said power distribution line.

19. An electrical power distribution monitoring system according to claim 13, wherein said calculating means is arranged further to calculate, from estimated electrical values in plural ones of said plurality of sections, the degree of deviation of said estimated electrical values from respective predetermined standard values.