Method and apparatus for setting trip profiles in electrical switches using a portable unit with a non-volatile memory

Trip profiles for electrical switches such as circuit breakers and overload relays can be generated, and when appropriate, coordinated, in a remote processor such as a personal computer. The profiles, with the addresses of the associated electrical switches are transferred into non-volatile memory in a portable unit. This portable unit is transported to the site of the electrical switches where it is interfaced with the appropriate electrical switch for loading of the assigned profile into the switch. In addition, the profiles stored in the electrical switches can be loaded into the portable unit for transport back to the remote unit for verification and/or modification.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to electrical switches such as circuit breakers and 
overload relays having trip profiles, and more particularly, to apparatus 
and a method for setting and reading the trip profiles using a portable 
unit. 
2. Background Information 
Electrical switches of the types such as circuit breakers and overload 
relays respond to a set of parameters characterizing current flowing 
through the switch known as trip profiles to automatically open the 
switch. In state of the art electrical switches, the trip profiles are 
implemented by a microprocessor which stores the characterizing parameters 
in a memory. These trip profiles are established by setting values for the 
characterizing parameters. Typically, this is performed by a set of 
switches on the electrical switch. In some cases, rather than having a set 
of switches on each electrical switch, a portable unit is temporarily 
connected to the circuit breaker and the profile is set by switches on the 
portable unit. In some installations, such as for instance in a plant 
power distribution system, each of the electrical switches, is connected 
to a remote personal computer which can set the trip profiles remotely. 
The trip profiles of state of the art circuit breakers have become quite 
complex, thereby requiring a certain level of skill and attention to 
setting them correctly. This is particularly important in systems where 
the trip profiles of the various switches are coordinated. For instance, 
in an electric power distribution system the trip profiles of circuit 
breakers lower in the hierarchy of the distribution system are set so that 
those circuit breakers will respond before circuit breakers higher up in 
the hierarchy to thereby isolate a fault as much as possible. The 
coordination of the trip profiles is performed by a skilled engineer, 
typically remotely from the distribution system. The various parameters 
establishing the trip profiles are then taken to the field where they are 
inserted by other less skilled individuals. This manual setting of the 
trip profiles is susceptible to human errors, and is otherwise time 
consuming. 
There is a need for an approved apparatus and method for setting trip 
profiles in electrical switches such as circuit breakers and overload 
relays, and particularly those controlled by microprocessors. 
There is a further need for such an improved method and apparatus which 
improves the integrity of setting the trip profiles in such electrical 
switches. 
There is yet another need for such an apparatus and method which reduces 
the time in the field required to set the trip profiles. 
There is yet another need for such an apparatus and method which reduces 
the level of skill required to reliably set the trip profiles in the 
field. 
There is still another need for such an apparatus and method which 
simplifies and assures the integrity of coordinated trip profiles. 
There is a further need for having available a reliable record of trip 
settings for resetting after breaker maintenance or replacement. 
SUMMARY OF THE INVENTION 
These needs and others are satisfied by the invention which is directed to 
apparatus and a method for setting and reading trip profiles in electrical 
switches such as circuit breakers and overload relays. A portable unit 
which is temporarily interfaced with the electrical switch contains a 
non-volatile memory in which trip profiles are stored. The portable unit 
is interfaced with the electrical switch through communication means in 
the switch using the unique address assigned to the switch. The profiles 
can be generated remotely from the switch by a remote processor such as a 
personal computer. The portable unit is temporarily connected with the 
remote processor for uploading of the trip profiles, together with the 
associated addresses, into the non-volatile memory of the portable unit. 
The portable unit is then transported to the location of the electrical 
switch for uploading into the trip unit of the switch identified by the 
unique address associated with each profile. This arrangement provides a 
reliable, efficient way of assuring that the proper trip profile is 
entered into each of the switches. This is particularly important where 
the trip profiles are coordinated, such as in an electric power 
distribution system. 
The portable unit can also be utilized to download trip profiles from the 
electrical switches for transport to a remote processor for verification 
and for modification. The modified trip profiles can then be transported 
in the non-volatile memory of the portable unit back to the electrical 
switch for upload. 
In particular, the invention includes the combination of at least one 
electrical switch having trip means tripping the separable contacts open 
in response to currents which exceed an assigned trip profile comprising a 
set of parameter settings, and communication means for transmitting and 
receiving messages incorporating the assigned trip profile. The 
combination further includes a portable unit separate from the switch and 
having non-volatile memory means for storing a plurality of trip profiles, 
and interface means for temporarily interfacing the portable unit with the 
communication means in the electrical switch. The portable unit further 
includes processor means for controlling transfer of the trip profiles in 
at least one direction between the trip means and the non-volatile memory 
through the interface means in the portable unit and the communication 
means in the switch. Where there are a plurality of switches, the 
communication means incorporates a unique address for the switch and the 
non-volatile memory of the portable unit stores an address with each 
profile. The combination further includes a remote processor having means 
generating the profiles with the unique addresses and means temporarily 
connecting the portable unit to the remote processor for transferring trip 
profiles with their associated addresses between the remote processor and 
the non-volatile memory of the portable unit. The invention also embraces 
the method of setting and reading trip profiles in electrical switches.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention will be described as applied to an electric power 
distribution system in which the electrical switches are circuit breakers. 
However, it will be understood by those skilled in the art that the 
invention has application to other types of systems incorporating 
electrical switches with intelligence and a communications system with 
which it can interface with the invention. 
As shown in FIG. 1, the electrical distribution system 1 includes a number 
of branches 3.sub.1, 3.sub.2, to 3.sub.n each protected by a circuit 
breaker 5.sub.1, 5.sub.2, to 5.sub.n. Each of circuit breakers 5 has a 
trip unit 7 which monitors current flowing in the associated branch 3 and 
sensed by a current transformer (CT) 9.sub.1 to 9.sub.n. The trip unit has 
stored therein a trip profile which is defined by a number of parameter 
settings, including the current sensed by the CTs 9. When a current 
exceeds the values determined by the trip profile, the affected circuit 
breaker trips, thereby opening separable contacts 11.sub.1, to 11.sub.n to 
interrupt to enter the current flowing in the associated branch 3. 
The circuit breakers 5.sub.1, to 5.sub.n each also include a communications 
module 13 which interfaces the circuit breaker with a network 15. The 
network 15 includes a master station 17. Typically, the network operates 
in a master/slave mode with the master station serving as the master and 
the circuit breakers 5 operating in the slave mode. In this arrangement, 
each of the circuit breakers 5 has an assigned, unique address so that the 
master station 17 can transmit messages directed only to a selected 
circuit breaker. The circuit breaker can then respond by sending a message 
which includes its unique address. Such an arrangement is described in 
U.S. Pat. No. 5,596,473 which is hereby incorporated by reference. 
In accordance with the invention, a hand held, portable unit 19 can be 
interfaced with the communications module 13 in a particular circuit 
breaker 5 through a plug-in connector 21 and an input/output (I/O) unit 23 
in the portable unit 19. The portable unit further includes a non-volatile 
memory 25 and processor 27 as described in U.S. Pat. No. 5,596,473. When 
the portable unit 19 is plugged into the circuit breaker 5, the 
communications module 13 is disconnected from the network 15 and instead 
responds to messages from and returns messages to the portable unit 19. 
The non-volatile memory 25 in the portable unit 19 stores a plurality of 
trip profiles. The user can select a profile, in a manner to be discussed, 
for uploading into the trip unit of the circuit breaker to which the 
portable unit is connected. In this arrangement, the same trip profile can 
be uploaded into a number of the circuit breakers 5. In another form of 
the invention, the unique address of one of the circuit breakers is 
associated with each profile so that an assigned profile is uploaded to 
the correct circuit breaker. In this latter arrangement, the portable unit 
can be used to read the address of the circuit breaker to which it is 
interfaced so that the correct profile can be selected from the 
non-volatile memory. The portable unit 19 can also be used to download the 
profile in the trip unit of the circuit breaker to which it is connected 
for purposes to be discussed. Such downloaded profiles are stored with the 
address of the circuit breaker from which the profile was obtained for 
later identification. 
The portable unit 19 can be transported to the site of a remote processor 
29, such as a personal computer (PC), and interfaced through the connector 
21 and a communications port 31 in the PC. The trip profiles which are 
uploaded by the portable unit 19 into the various circuit breakers 5 can 
be generated in the remote processor 29. This remote processor can be the 
personal computer of the skilled engineer who determines the parameter 
settings for the various trip profiles. As is known, the trip profiles for 
the circuit breakers 5 in a hierarchial distribution system can be 
coordinated so that the circuit breaker closest to a fault in the 
distribution system trips first, and therefore limits disruption of the 
distribution system 1. The addresses of the circuit breakers to which the 
various trip profiles are assigned are loaded into the non-volatile memory 
in the portable unit 19 by the remote processor 29. A semi-skilled worker 
can then transport the portable unit 19 to the site of the distribution 
system for uploading of the profiles into the different circuit breakers 
5. As the addresses of the circuit breakers are associated with the 
profile, the risk of uploading the profile into the wrong circuit breaker 
is virtually eliminated. Also, since the uploading is automatic, it is 
rapid and avoids errors in entry. As another aspect of the invention, the 
trip profiles in the circuit breaker can be downloaded into the portable 
unit, transported to the site of the remote processor 29, and uploaded for 
verification with a master table stored in the remote processor. These 
profiles can also be modified as necessary and returned for uploading into 
the circuit breakers 5. Since the portable unit 19 has a non-volatile 
memory, it can be used for long-term storage of the assigned trip profiles 
which may be recalled for uploading to a replacement circuit breaker or to 
otherwise reprogram a circuit breaker in the field. 
As shown in FIG. 2, the portable unit 19 has a 16 character display 33 
which presents a menu of available functions including selection of 
uploading and downloading of trip profiles. This menu may be scrolled by 
membrane switches 35, 37 and 39. A selected function is implemented by 
pressing the "select" membrane switch 41. A "save" button 43 can be used 
in conjunction with the "select" button 41 to confirm certain actions such 
as deleting a profile. The portable unit 19 is powered up or down by the 
"on/off" button 45. An increase button 47, and a decrease button 49, are 
used for performing other unrelated functions in the portable unit 19. 
FIG. 3 is a flow chart 51 of the operation of the portable unit 19. The 
"set point profile" is selected at 53 from the main menu presented on the 
display 33. This produces a new display which prompts the user to either 
select from the set point profiles stored in the non-volatile memory 25 or 
to save a set point profile to the memory 25. There are three submenus of 
the main menu item "set points profile." The first is a "save set points" 
menu 55, a second is a "retrieve set points" submenu 57, and the third is 
a "delete profile" submenu 59. 
The "save set point" submenu 55 can save a profile to the non-volatile 
memory 25 by either downloading a profile developed on the remote 
processor at 61 or by retrieving a profile from a trip unit previously 
programmed at 63. If the "save from computer" option is selected at 61, a 
specified circuit breaker address is normally required. If the trip 
profile is saved from a circuit breaker, the address of the circuit 
breaker will be retained with the profile in the memory 25. In either 
case, an available location in the non-volatile memory 25 is determined at 
65 and the profile is saved at 67 before the program returns to the main 
memory at 69. The "retrieve set points" 57 function is used to read 
profiles from the non-volatile memory 25 of the portable unit that were 
previously downloaded either from the remote processor 29 or a trip unit 7 
of a circuit breaker 5. Once the "retrieve set points profile" has been 
selected, a list of profiles designated as P1, P2 . . . Pn are displayed 
on the display 33. The selection of a profile is performed by moving a 
cursor with the "right" button 39 or "left" button 35. The "select" button 
41 is then pressed simultaneously with the "save" button 43 to select a 
profile. Upon successful retrieval of a profile, the portable unit will 
display that the profile selected has been retrieved. It may be desirable 
to view the set point settings of the profile as indicated at 73. In order 
to display the settings in terms of current, an artificial rating plug and 
frame value needs to be entered. The user can be prompted to do this on 
the display 33 and can adjust the settings using the increase and decrease 
buttons 47 and 49. The view profile submenu 73 allows the user to view the 
address of the trip unit that the portable unit saved the profile from or 
the address that the profile was saved at by the remote processor. This 
address may be edited if a password is entered. 
The selected profile is downloaded at 77 by simultaneously pressing the 
"save" button 43 and the "select" button 41. A message "downloading 
profile PX to (address)" is displayed on the display 33. When the download 
is complete, the program returns to the main menu at 69. 
If a profile is no longer needed, it may be desirable to delete it from the 
non-volatile memory 25. As mentioned, this can be accomplished through the 
"delete profiles" submenu at 59 under the main menu item "set points 
profiles." A listing of all of the profiles that have been saved will be 
displayed by pressing the "save" 43 and "select" 41 buttons. A cursor will 
flash on the first saved profile designation such as P1 or P2. By moving 
the cursor with the "right" button 39 or "left" button 35, the various 
profile designators are displayed. With the cursor on the profile to be 
deleted, the "save" button 43 and the "select" button 41 are pressed 
simultaneously at 79. A message "Are you sure?" will be displayed at 81. 
The message "No" will appear in the bottom right hand corner of the 
display 33. By pressing the "up" button 37, the word "Yes" will toggle 
into the lower right screen. Then by simultaneously pressing the "save" 43 
button and the "select" button 41 the selected profile is deleted at 83. 
The set up of circuit breaker set points during installation can be time 
consuming and sometimes confusing to the technician or engineer. By 
pre-determining the various set points in a trip profile on a remote 
processor, such as a PC, and downloading them to the portable unit 19, 
little time is spent in the field setting up circuit breaker trip 
profiles, and erroneous coordination is virtually eliminated. Using a 
personal computer with a communications module, the trip profiles, which 
are configured using Windows or DOS compatible software, can be downloaded 
to the portable unit. Several circuit breaker profiles can be stored in 
the portable unit and then downloaded to the circuit breakers in the 
field. The upload feature allows the portable unit to return profiles to 
the personal computer as well. These advantages provided by the invention 
save time, but most importantly, improve the accuracy of setting up 
profiles in electrical switching apparatus such as circuit breakers, 
overload relays and the like. 
While specific embodiments of the invention have been described in detail, 
it will be appreciated by those skilled in the art that various 
modifications and alternatives to those details could be developed in 
light of the overall teachings of the disclosure. Accordingly, the 
particular arrangements disclosed are meant to be illustrative only and 
not limiting as to the scope of the invention which is to be given the 
full breadth of the claims appended and any and all equivalents thereof.