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US 9,318,920 B2Granted
Method and system for the installation of fault circuit indicators on an electrical feeder
AssigneeBaltimore Gas and Electric Company
InventorsAleksandar Vukojevic, Paul Frey
Life of this patent
Estimating the term…
Abstract
A method for maximizing the benefits of Fault Circuit Indicators on an electrical feeder has two steps. In the first step a data set for the feeder is obtained based on historical data. In the second step, the number of FCIs and their location is calculated based on the data set obtained in the first step. The number of FCIs and their location is determined utilizing a simulation algorithm that ensures each FCI is used efficiently and provides actionable information to the utility's crew.
Claims26
A method for maximizing efficient placement of Fault Circuit Indicators (FCIs) on an electrical feeder, comprising the steps of:
- obtaining a data set associated with faults on an electrical feeder, wherein said data set includes overhead and underground fault response information;
- identifying a number of FCIs and a location of each FCI on the feeder utilizing information contained in the data set, wherein said information comprises at least one of overhead, underground fault response information, and probabilities of overhead and underground faults in the feeder, wherein said number of FCIs and location of each FCI results in a reduction of customer average outage time (AOT) for the feeder, wherein said AOT is determined from the equation:
- AOT
- =
- ∑
- i
- =
- 1
- i
- =
- N
- z
-
- (
- ∑
- c
- =
- 1
- c
- =
- N
- CZi
-
- COT
- ci
- *
- p
- Zi
- )
- N
- C
- ,
- wherein
- COTci=outage time for customer C in a zone i;
- pZi=probability of the fault in the zone i;
- NZ=total number of zones;
- NCZi=total number of customers in zone i;
- and
- NC=total number of customers per feeder;
- and
- wherein said identifying step comprises the steps of:
- a. selecting a feeder Customer Average Interruption Duration Index (CAIDI) value for reference;
- b. calculating a number of zones for each feeder and identifying sections in each zone, determining number of customers per each zone and each section in the zone, number of miles of a particular conductor in each zone and section, and type of the cable (overhead (“OH”) or underground (“UG”));
- c. obtaining values for times associated with initiating a fault ticket, initial drive to a substation, line inspection time and line repair time;
- d. determining coefficients c1 and c2, wherein c1 and c2 comprise constants that sum to 1 and that correspond to the percent of total faults that comprise faults of a specific origin;
- e. calculating ξ, such that customer AOT+ξ=CAIDI from step a:
- AOT
- =
- ∑
- i
- =
- 1
- i
- =
- N
- z
-
- (
- ∑
- c
- =
- 1
- c
- =
- N
- CZi
-
- COT
- ci
- *
- p
- Zi
- )
- N
- C
- +
- ξ
- =
- CAIDI
- f. calculating the values for probability of fault occurrence for each section of each zone by using the formula:
- p
- Z
-
-
- i
- =
- c
- 1
-
- (
- p
- UG
-
- M
- UG
-
-
- i
- +
- p
- OH
-
- M
- OH
-
-
- i
- p
- UG
-
- M
- UGz
- +
- p
- OH
-
- M
- OHz
- )
- +
- c
- 2
-
- N
- PD_zi
- N
- PD_z
- ,
- wherein
- pUG=percentage of faults on underground cables,
- MUGi=number of underground cable miles in zone i,
- pOH=percentage of faults on overhead cables,
- MUGz=number of overhead cable miles in zone i,
- MOHz=total feeder number of underground cable miles,
- MOHz=total feeder number of overhead cable miles,
- NPD_Zi=number of protective devices in zone i, and
- NPD_z=number of protective devices on the feeder:
- g. randomly choosing nodes on the feeder where the FCIs are to be placed:
- h. calculating fault probabilities using a simulation algorithm to simulate faults on the feeder;
- i. calculating the mode for AOT based on the simulation and making it the baseline AOT;
- j. defining the maximum number of generations as (kn) where n is the total number of nodes on the feeder, k is the number of desired sets of FCIs, and the number of generations is representative of the number of ordered sets of FCIs that can be made from a set of nodes of size n;
- k. selecting a node randomly in a sequence of the FCI placement from step h;
- l. selecting another node on the feeder that has no FCI associated with it, place the FCI from the node from step k at that node and calculating the new AOT using the same procedure as in steps h-i;
- m. if the new AOT (mode) is lower than the baseline AOT, making the new AOT the baseline value, and selecting the new FCI placement as optimum placement;
- n. returning to step k until the minimum AOT (mode) has been reached, or until the maximum number of generations has been reached;
- o. changing the number of FCIs, and repeating the procedure starting at the step g
- p. comparing the values for AOT for each number of FCIs installed;
- and
- q. selecting the appropriate number and location of FCIs;
- and placing the identified number of FCIs at the identified locations on the feeder.
147 more elements
A system for maximizing efficient placement of Fault Circuit Indicators (FCIs) on an electrical feeder, comprising:
- an electrical feeder forming at least a portion of an electric distribution network;
- a data management module configured to store a data set;
- a FCI placement module configured to process feeder data and identify a number of FCIs and a location of each FCI on the feeder utilizing information contained in the data set, wherein said information comprises at least one of overhead, underground fault response information, and probabilities of overhead and underground faults in the feeder, wherein said number of FCIs and location of each FCI results in a reduction of customer average outage time (AOT) for the feeder wherein said AOT is determined from the equation:
- AOT
- =
- ∑
- i
- =
- 1
- i
- =
- N
- z
-
- (
- ∑
- c
- =
- 1
- c
- =
- N
- CZi
-
- COT
- ci
- *
- p
- Zi
- )
- N
- C
- ,
- wherein
- COTci=outage time for customer C in a zone i;
- pZi=probability of the fault in the zone i;
- Nz=total number of zones;
- NCZi=total number of customers in zone i;
- and
- NC=total number of customers per feeder;
- and
- wherein said identifying step comprises the steps of:
- a. selecting a feeder Customer Average Interruption Duration Index (CAIDI) value for reference;
- b. calculating a number of zones for each feeder and identifying sections in each zone, determining number of customers per each zone and each section in the zone, number of miles of a particular conductor in each zone and section, and type of the cable (overhead (“OH”) or underground (“UG”)),
- c. obtaining values for times associated with initiating a fault ticket, initial drive to a substation, line inspection time and line repair time;
- d. determining coefficients c1 and c2, wherein c1 and c2 comprise constants that sum to 1 and that correspond to the percent of total faults that comprise faults of a specific origin;
- e. calculating ξ, such that customer AOT+ξ=CAIDI from step a:
- AOT
- =
- ∑
- i
- =
- 1
- i
- =
- N
- z
-
- (
- ∑
- c
- =
- 1
- c
- =
- N
- CZi
-
- COT
- ci
- *
- p
- Zi
- )
- N
- C
- +
- ξ
- =
- CAIDI
- f. calculating the values for probability of fault occurrence for each section of each zone by using the formula:
- p
- Z
-
-
- i
- =
- c
- 1
-
- (
- p
- UG
-
- M
- UG
-
-
- i
- +
- p
- OH
-
- M
- OH
-
-
- i
- p
- UG
-
- M
- UGz
- +
- p
- OH
-
- M
- OHz
- )
- +
- c
- 2
-
- N
- PD_zi
- N
- PD_z
- ,
- wherein
- pUG=percentage of faults on underground cables,
- MUGi=number of underground cable miles in zone i,
- pOH=percentage of faults on overhead cables,
- MUGz=number of overhead cable miles in zone i,
- MOHZ=total feeder number of underground cable miles,
- MOHz=total feeder number of overhead cable miles,
- NPD_zi=number of protective devices in zone i, and
- NPD_z=number of protective devices on the feeder:
- g. randomly choosing nodes on the feeder where the FCIs are to be placed;
- h. calculating fault probabilities using a simulation algorithm to simulate faults on the feeder;
- i. calculating the mode for AOT based on the simulation and making it the baseline AOT,
- j. defining the maximum number of generations as (kn), where n is the total number of nodes on the feeder, k is the number of desired sets of FCIs, and the number of generations is representative of the number of ordered sets of FCIs that can be made from a set of nodes of size n;
- k. selecting a node randomly in a sequence of the FCI placement from step h;
- l. selecting another node on the feeder that has no FCI associated with it, place the FCI from the node from step k at that node and calculating the new AOT using the same procedure as in steps h-i;
- m. if the new AOT (mode) is lower than the baseline AOT, making the new AOT the baseline value, and selecting the new FCI placement as optimum placement;
- n. returning to step k until the minimum AOT (mode) has been reached, or until the maximum number of generations has been reached;
- o. changing the number of FCIs, and repeating the procedure starting at step g;
- p. comparing the values for AOT for each number of FCIs installed;
- and
- q. selecting the appropriate number and location of FCIs;
- and placing the identified number of FCIs at the identified locations on the feeder.
148 more elements
Dependencies are inferred from the claim text.