Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-04-16
2001-03-06
Lieu, Julie (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S286010, C340S286020
Reexamination Certificate
active
06198402
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a power system protection and control terminal for protection and control of a power system by operating switches such as circuit breakers in response to state variables input from the power system, a power system monitoring and control system, and a storage medium in which a program is stored.
In particular, the storage medium relates to a power system protection and control terminal equipped with a function for performing correlation processing of a protective relay and, a switch operation, a power system monitoring control system and a storage medium for storing a program.
DESCRIPTION OF THE RELATED ART
A power system monitoring and control system has a plurality of protection and control terminals arranged, for example, corresponding to each substation constituting the power system and that perform protection and control of the power system in accordance with state variables such as currents or voltages obtained from the power system, and a power system monitoring and control host that performs monitoring and/or control of this power system by receiving information of various types relating to the power system sent from these plurality of protection and control terminals through a transmission system (power system information: for example, open/closed state of circuit breakers, bus voltages, power flow of transmission lines and their frequency etc.) and displays the power system information which it receives.
FIG. 11
shows an example of a circuit block layout of a prior art power system monitoring and control system
10
.
A power system monitoring and control system
10
comprises a plurality of protection and control terminals
12
-
1
-
12
-n that perform protection and control of a power system
11
, and a power system monitoring and control host
14
that monitors and controls the power system
11
using power system information of various types (for example, the open/closed state of circuit breakers etc.) that it receives which is transmitted through a transmission system
13
from these plurality of protection and control terminals
12
-
1
-
12
-n. It should be noted that although
FIG. 11
shows only the circuit block layout of a single protection and control terminal
12
-
1
, the block layout of the other protection and control terminals
12
-
2
. . .
12
-n are omitted from the drawing, as their circuit block layouts are identical with that of protection and control terminal
12
-
1
.
As shown in
FIG. 11
, protection and control terminal
12
-
1
consists of a protective relay circuit
21
, a CB control circuit
22
, a re-closure circuit
23
, a CB state-receiving circuit
24
, and a system state transmission circuit
25
.
The protective relay circuit
21
has one or more (for example three) relay elements (these could be simply relays or relay unit software, for example, a main protective ground relay, a main protective short-circuit relay and a backup short-circuit relay), that detects system fault of the power system
11
by operation of the relay elements in response to state variables input from the power system
11
.
The CB control circuit
22
outputs tripping/closure instructions to a switch such as a circuit breaker {hereinafter called circuit breaker (CB)
11
a
} located on a transmission line or bus etc. for tripping a system circuit constituting the power system
11
in response to operation of these protective relay circuits
21
(the relay element
21
a
1
-
21
a
3
, which is not described in figure.).
The re-closure circuit
23
performs re-closure processing of the CB
11
a
by means of the CB control circuit
22
as required in response to operation of the protective relay circuit
21
.
The CB state-receiving circuit
24
gets the open/closed state of the CB
11
a.
The system state transmission circuit
25
sends it to the power system monitoring and control host
14
through the transmission system
13
power system information including the operating state of the relay elements
21
a
1
-
21
a
3
of the protective relay circuit
21
, the operating state of the reclosure circuit
23
and the open/closed state of the CB
11
a
that is obtained by the CB state receiving circuit
24
.
In
FIG. 11
, the protection and control terminal
12
-
1
is shown as effecting tripping/closure operation of the single CB
11
a
using a plurality of relay elements
21
a
1
-
21
a
3
.
But, in fact, tripping/closure operation is performed for a respective plurality (for example two) of the CB
11
a
,
11
b
, using a plurality of relay elements
21
a
1
-
21
a
3
.
For example, respective tripping/closure operation is performed of the relay element
21
a
1
→CB
11
a
, relay elements
21
a
2
,
21
a
3
→CB
11
b.
The power system monitoring and control host
14
has a state change detection unit
41
, a state change data file storage unit
42
, a CB relay correlation unit
43
, an associated state change message file storage unit
44
and a CB operation display unit
45
.
The state change detection unit
41
receives power system information sent from the plurality of the protection and control terminals
12
-
1
-
12
-n through the transmission system
13
, and detects when there is a change in the state of the power system
11
from this received power system information (hereinafter abbreviated to “state change”).
The state change detection unit
41
sends to a CB relay correlation unit, to be described, later state change data which it compiles from the detected state changes, appending thereto the time-point of detection; and the state change data file storage unit
42
that stores in file form the state change data compiled by the state change detection unit
41
.
The CB relay correlation unit
43
compiles a message (also called associated state change message or state change message) associating the CB operation state changes (also called CB state changes) and relay operation state changes (also called relay state changes) by effecting correlation of the CB operating state changes and relay operating state changes, using for this purpose the state change data that was transmitted.
The associated state change message file storage unit
44
stores in the form of a file the associated state change message compiled by the CB relay correlation unit
43
The CB operation display unit
45
provided with a display device such as a display (hereinafter termed a display) and reads the associated state change message (file) stored in the associated state change message file storage unit and displays this on the display screen.
FIG. 12
shows an example of the transmission format of the power system information that is received by a power system monitoring and control host
14
through the transmission system
13
.
As shown in
FIG. 12
, the power system information that is sent at fixed intervals from the protection and control terminals
12
-
1
-
12
-n is transmitted to the power system monitoring and control host
14
as state data S comprising bit information sequences BD
1
, BD
2
, . . . located at each substation (substation A, substation B and substation C, . . . ) constituting the power system
11
, in accordance with the transmission format, by transmission system
13
.
The bit information sequences BD
1
, BD
2
, . . . of the substations constituting state data S include;
1) a one-bit information representing the operating state of the protective relay circuit
21
of which the subject of protective relay action is an equipment or device within the corresponding substation/the operating state of the re-closure circuit
23
of which the subject of re-closure action is an equipment or a device within the corresponding substation, and
2) a one-bit information representing the open/closed state of the CB provided in this equipment/device.
For example, as shown in
FIG. 12
, if the single-bit information of the relay element, the subject of whose protective action is the XX transmission line
1
L is “0”, this means that this relay element is in a reset state; if the single-bit information of the CB tha
Hasegawa Osamu
Kaino Yasuo
Sirota Yosihiro
Foley & Lardner
Kabushiki Kaisha Toshiba
Lieu Julie
LandOfFree
Electric power system protection and control system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric power system protection and control system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric power system protection and control system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2502051