ZLB current limiting device based on current judgment
Technical field:
the invention relates to the field of electric power, in particular to a ZLB current limiting device based on current judgment.
The background technology is as follows:
as is well known, when a short circuit fault occurs in a power system, the short circuit current is generally ten times as high as the fault current, which causes great harm to a transformer, a breaker and a transmission line, while the current economical and practical vacuum breaker has the breaking capacity of less than 40KA, the breaking capacity of the high-speed switch needs 40 to 60 ms, as the development of various power enterprises is strong, the power load is greatly increased, the main transformer capacity is correspondingly increased, the power grid systems of enterprises face the maximum practical limit of the short circuit current to approach the breaker, the open end capacity of the breaker is insufficient, the short circuit current impact of the transformer is insufficient, the safe operation of the power grid is seriously threatened, so that most transformer substations are connected in series with the series reactance, and the current ZLB current limiter is also known as the breaking risk of the high-speed switch after judging that the fault current is limited by a manufacturer after the current is greater than a certain value, the fault is eliminated, the high-speed switch is always in a breaking position at the moment after the fault is eliminated, and the high-speed switch is always in a breaking position. The improved control strategy can switch the breaker by means of current criteria, and can stop the occurrence of the accidents.
The invention comprises the following steps:
the invention aims to provide a ZLB current limiting device based on current criteria, which has the advantages of no load, high reliability, stable operation and high response speed.
The invention is realized by the following technical scheme:
the invention relates to a ZLB current limiting device based on a current criterion, which comprises an inverter, a current limiting reactor, a field operation cabinet and a central control room, wherein: the converter is connected with the current limiting reactor in parallel; the converter is connected in series in the power supply line; the converter is connected with the field operation cabinet; the field operation cabinet is connected with the central control room; the converter comprises a phase controller, a circuit breaker, a Rocker CT coil and a return CT coil; the circuit breaker, the Rocker CT coil and the return CT coil are connected in series in a power supply circuit; the circuit breaker, the Rocker CT coil and the return CT coil are respectively connected with the controller; the current limiting reactor is connected with the circuit breaker and the Rocker CT coil in parallel; the phase controller is connected with the operation cabinet.
The ZLB current limiting device based on the current criterion, wherein: the operation cabinet comprises a relay controller, an optical fiber terminal and a terminal strip; the central control room comprises a control room background, a wave recorder and a display device; the optical fiber terminal is connected with the phase controller through an optical fiber; the terminal strip is electrically connected with the phase controller; the central control chamber is electrically connected with the terminal strip; the control room background and the wave recorder are connected with the terminal strip; the display device is electrically connected with the recorder.
The ZLB current limiting device based on the current criterion, wherein: the judgment control is performed by the following control strategy steps:
a. when the current detected by the Rogowski CT coil is greater than 6.9KA, the switch is opened;
b. returning to the CT coil, and carrying out the next step if the current detected by the CT coil is greater than 2.2 KA; when the current is detected to be less than or equal to 2.2KA, switching-on operation is carried out, and the system is restored to an initial state;
c. continuously closing for 2S once;
d. returning to the CT coil, and carrying out the next step when the current detected by the CT coil is larger than 1 KA; when the current is detected to be less than or equal to 1KA, switching on operation is carried out, and the system is restored to an initial state;
e. the switching-on is unsuccessful, and the main transformer outlet 1 is jumped;
or:
a. the Rogowski CT coil does not detect a current greater than 6.9KA and returns to the CT coil 104 for detection
When the current is greater than the set value 100A;
b. closing once;
c. returning to the CT coil to carry out the next step when the current lasting for 2s is larger than 100A; inspection and detection
When the continuous current of 2s is detected to be less than or equal to 100A, closing operation is carried out, and the system is restored to an initial state;
d. and the switching-on is unsuccessful, and the main transformer outlet 2 is jumped.
The ZLB current limiting device based on the current criterion, wherein: the circuit breaker is an "eddy current driven" fast circuit breaker.
The invention has the beneficial effects that: the control strategy after improvement is used for switching the main transformer low-voltage side circuit breaker through the current criterion, and meanwhile, the fault self-healing successful action logic criterion is added, so that the control strategy can meet the condition of various faults, has no load loss in the station and ensures the reliability of power supply.
Description of the drawings:
fig. 1: a schematic diagram of the present invention;
fig. 2: the control strategy judgment chart of the invention;
in the figure: 1-converter, 101-phase controller, 102-circuit breaker, 103-roc CT coil, 104-return CT coil, 2-current limiting reactor, 3-field operation cabinet, 301-relay controller, 302-optical fiber terminal, 303-terminal row, 4-central control room, 401-control room background, 402-recorder and 403-display device.
The specific embodiment is as follows:
the invention is further described with reference to the drawings and detailed description which follow:
examples: as shown in fig. 1 and 2, a ZLB current limiting device based on a current criterion includes an inverter 1, a current limiting reactor 2, a field operation cabinet 3 and a central control room 4, wherein: the converter 1 is connected with the current limiting reactor 2 in parallel; the converter 1 is connected in series in a power supply line; the converter 1 is connected with the field operation cabinet 3; the field operation cabinet 3 is connected with the central control room 4; the inverter 1 comprises a phase controller 101, a circuit breaker 102, a roc CT coil 103 and a return CT coil 104; the circuit breaker 102, the roc CT coil 103 and the return CT coil 104 are connected in series in the power supply line; the circuit breaker 102, the roc CT coil 103 and the return CT coil 104 are respectively connected with the controller 101; the current limiting reactor 2 is connected with the circuit breaker 102 and the roc CT coil 103 in parallel; the phase controller 101 is connected with the operation cabinet 3; wherein: the operation cabinet 3 includes a relay controller 301, an optical fiber terminal 302, and a terminal block 303; the central control room 4 comprises a control room background 401, a recorder 402 and a display device 403; the optical fiber terminal 302 is connected to the phase controller 101 with an optical fiber; the terminal block 303 is electrically connected to the phase controller 101; the central control room 4 is electrically connected with the terminal row 303; the control room background 401 and the recorder 402 are connected with the terminal block 303; the display device 403 is electrically connected to the recorder 402; wherein: the circuit breaker 102 is an "eddy current driven" fast circuit breaker.
Wherein: the judgment control is performed by the following control strategy steps:
a. when the Rogowski CT coil 103 detects that the current is greater than 6.9KA, the switch is opened;
b. the return CT coil 104 detects that the current is greater than 2.2KA, and then the next step is carried out; when the current is detected to be less than or equal to 2.2KA, switching-on operation is carried out, and the system is restored to an initial state;
c. continuously closing for 2S once;
d. the return CT coil 104 carries out the next step when detecting that the current is larger than 1 KA; when the current is detected to be less than or equal to 1KA, switching on operation is carried out, and the system is restored to an initial state;
e. the switching-on is unsuccessful, and the main transformer outlet 1 is jumped;
or:
e. the Rogowski CT coil 103 does not detect a current greater than 6.9KA and returns to the CT coil 104 for detection
When the current is greater than the set value 100A;
f. closing once;
g. the return CT coil 104 detects that the continuous 2s current is more than 100A, and then proceeds to the next step; inspection and detection
When the continuous current of 2s is detected to be less than or equal to 100A, closing operation is carried out, and the system is restored to an initial state;
d. and the switching-on is unsuccessful, and the main transformer outlet 2 is jumped.