System for rating electric power transmission lines and equipment

• US 5,341,088 A
• Filed: 07/13/1992
• Issued: 08/23/1994
• Est. Priority Date: 06/22/1984
• Status: Expired due to Term

• Current Assignee: Murray W. Davis
• Original Assignee: Murray W. Davis
• Inventors: Davis, Murray W.
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US07/912,813
• Time in Patent Office: 771 Days
• Field of Search: 324/106, 324/105, 324/107, 324/95, 324/142
• US Class Current: 324/106
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 15/14 Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
• CPC Class Codes: G01R 19/15 Indicating the presence of current
• CPC Class Codes: H02J 13/00016 using a wired telecommunication network or a data transmission bus
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/00 Systems supporting electrical power generation, transmission or distribution
• CPC Class Codes: Y04S 40/124 using wired telecommunication networks or data transmission busses

Abstract

A system for determining the current carrying capability of one or more overhead power transmission lines monitors one or more spans of each line on real-time basis and identifies the span having the lowest current carrying capacity which in turn establishes the maximum capacity of the entire line. The thermal state of each monitored line span is determined by measuring the conductor temperature, line current, solar radiation, ambient temperature, and in some cases wind speed and wind direction. These parameters are montiored by a sensor-transmitter unit that may be removably clamped on the line conductor which may range in size from one to several inches in diameter, and includes a radio transmitter for transmitting sensed data to a receiving substation. The data from the sensor-transmitter is multiplexed and transmitted by a telecommunications link to a computer which automatically determines line capacity using the real-time data and also calculates the time required for the "critical span" having the lowest current capacity to reach its maximum safe temperature based on any of a number of step changes in load demands. Each sensor-transmitter may include sensors for monitoring the current level, conductor temperature, solar radiation impinging on the conductor, ambient-temperature, wind direction and velocity and conductor sag.

Claims

1. A method for monitoring the current carrying capacity of a length of an overhead electric power line, which includes a plurality of overhead electric power line spans supported above the ground, comprising the steps of:

a. positioning a monitoring device for monitoring the distance between the ground and the overhead electric power line on at least one span of the length of said overhead electric power line in such a way as to not significantly affect the distance between the ground and said at least one span;

b. monitoring on a real-time basis the distance between the ground and said at least one span of the length of said overhead electric power line;

c. generating data signals at the monitored spans corresponding to the monitored distance between the ground said at least one span;

d. determining the current carrying capacity of said electric power line span using at least the data signals generated in step (c).

2. The method of claim 1, wherein the distance between the ground and said at least one span is calculated by measuring the actual sag in said at least one span by said monitoring device.

3. The method of claim 2, wherein said monitoring step is performed by continuously sensing the slope of said overhead electric power line along said at least one span and generating data signals in response thereto.

4. A method for monitoring the current carrying capacity of a length of an overhead electric powerline, which includes a plurality of overhead electric power line spans supported above the ground, comprising the steps of:

a. positioning a monitoring device for monitoring the distance between the ground and the overhead electric power line on at least one span of the length of said overhead electric power line in such a way as to not significantly affect the distance between the ground and said at least one span;

b. monitoring on a real-time basis the sag of said at least one span to determine the distance between the ground and said at least one span of the length of said overhead electric power line, said sag being measured by measuring the slope of said at least one span;

c. generating data signals at the monitored spans corresponding to the monitored sag;

d. determining the current carrying capacity of said electric power line span using at least the data signals generated in step (c).