Disclosure of Invention
The invention aims to solve the technical problem of providing a quick ring-opening method for double loop circuit operation, which can ensure that the load distribution of a double loop circuit operation circuit is uniform, the circuit loss is low, the power supply reliability is high, and the total station voltage loss caused by a branch fault can be prevented.
In order to solve the technical problems, the invention adopts the technical scheme that:
the invention relates to a quick ring-opening method for double loop ring operation, which comprises the following steps:
1) the adopted double-loop annular operation line is as follows:
a. a power supply I bus and a power supply II bus of 110kv at the power supply side are connected in parallel through a bus coupler circuit breaker, and at least two main transformers are put into operation at the same time and are respectively connected to different power supply buses in a hanging manner at the power supply side;
b. a power receiving I bus and a power receiving II bus of a load side 110kv are in parallel and put into operation;
c. a plurality of groups of double circuit lines are connected between the power supply side and the load side in a hanging mode, and a branch circuit breaker is arranged on the power supply side and the load side of each of two single circuit lines in each group of double circuit lines and is put into operation;
d. the power supply sides of the two single circuit lines are respectively connected with different power supply buses in a hanging mode and put into operation; the load sides of the two single circuit lines are respectively connected with different power receiving buses and put into operation;
e. on the load side, a section breaker is connected between the two single circuit lines;
2) on the bus-coupled circuit breaker, a hard contact representing an on or off state is connected to a quick ring-opening device, and a cable is used for collecting the current direction flowing through the bus-coupled circuit breaker and the phase difference change value of the voltage at two ends of the bus-coupled circuit breaker;
3) the two branch isolation disconnecting link switching-on positions on each of the two single circuit lines are connected to the quick ring-opening device through hard contacts representing the on-off state so as to acquire confirmation information of the operation of the corresponding single circuit line hung on the power supply I bus or the power supply II bus;
4) and on the branch circuit breakers, hard contacts representing the on-off state are connected into the quick ring opening device, and when any branch circuit breaker on the power supply side fails to operate or is protected to operate, all branch circuit breakers on the power supply side hung on the power supply bus on the fault side are cut off.
The conditions for disconnecting the branch breaker of the power supply side, which is connected to the fault-side power supply bus, are as follows:
the main transformer protection of the transformer substation trips the bus-coupled circuit breaker, current flowing through the bus-coupled circuit breaker before tripping the bus-coupled circuit breaker flows to a power supply I bus from a power supply II bus, and all branch circuit breakers on the power supply side of the power supply I bus are connected in the double-circuit loop running circuit;
or,
the main transformer protection of the transformer substation trips the bus tie circuit breaker, current flowing through the bus tie circuit breaker before tripping the bus tie circuit breaker flows to a power supply II bus from a power supply I bus, and all branch circuit breakers hanging power supply sides on the power supply II bus in the double-circuit loop running circuit are disconnected.
Before a double-circuit branch line breaker hung on a fault side power supply bus is cut off, the quick ring-releasing device is charged, and the required logic conditions are as follows:
1) putting a 'quick ring-releasing' hard pressing plate;
2) putting into the ring wiring operation hard pressing plate of any group of double circuit lines;
3) the bus tie breaker is closed;
4) the power supply I bus meets the pressure condition, and the power supply II bus meets the pressure condition;
after the conditions 1) to 4) are met and 10 seconds are continued, the automatic switching device in the quick ring-opening device is charged;
the 'quick ring-opening' hard pressing plate and any 'annular wiring operation' hard pressing plate are switches arranged outside the quick ring-opening device.
The further conditions for disconnecting the branch breaker of the power supply side, which is connected to the fault-side power supply bus, are:
the branch circuit breaker of the power side that is connected to the I female of power supply to hanging is:
a1. completing the charging of the quick ring-releasing device;
a2. the current of the bus tie breaker reaches a starting condition;
a3. starting the quick ring-opening;
a4. the zero sequence current of the bus tie breaker meets the positive direction, or does not meet the zero sequence direction calculation condition and the phase current meets the positive direction;
a5. the bus tie breaker has no current;
a6. the bus re-pressing condition of the power supply I is met;
when the condition of a 1-a6. lasts for 40ms, the rapid ring-releasing device sends a command of rapidly cutting off the power supply I mother branch circuit action, and cuts off a branch circuit breaker hung on the power supply side of the power supply I mother circuit;
or,
the branch circuit breaker of the power side connected to the power supply II bus in a hanging mode is as follows:
b1. completing the charging of the quick ring-releasing device;
b2. the current of the bus tie breaker reaches a starting condition;
b3. starting the quick ring-opening;
b4. the zero sequence current of the bus tie breaker meets the reverse direction, or does not meet the zero sequence direction calculation condition and the phase current meets the reverse direction;
b5. the bus tie breaker has no current;
b6. the bus re-pressing condition of the power supply II is met;
when the condition of b 1-b6. lasts for 40ms, the quick ring-opening device sends a command of quickly cutting off the branch circuit of the II parent power supplies, and cuts off the branch circuit breaker on the power supply side where the II parent power supplies are hooked.
The power supply bus of the transformer substation adopts a double-bus main wiring mode or a single-bus section main wiring mode.
At least one single branch line which does not form a double loop annular operation mode and is put into operation is hung between the power supply side and the load side.
According to the invention, after the main transformer backup protection primary section time delay tripping bus-coupled circuit breaker on the power supply side and before the main transformer backup protection secondary section time delay action, the branch circuit breaker on the power supply side, which is hung on the fault side bus, is quickly cut off so as to unlock the operation of the double-circuit loop annular operation line.
The invention can also quickly cut off the branch circuit breaker connected with the fault side bus after the main transformer backup protection section delays to trip off the bus-coupled circuit breaker when the protection of the non-annular wiring operation line connected between the power supply side and the load side refuses, and cuts off the power transmission path of the normal bus to the fault point, thereby achieving the purposes of keeping the normal side bus load and preventing the fault range from being expanded, and improving the reliability of the double-circuit line annular operation line.
Detailed Description
The method is suitable for the wiring mode that the double-circuit line hanging bus is a double bus or a single bus section. The method of the invention adopts the following connection structure and is set as follows:
1. the quick ring-opening method of the invention aims at the following double-circuit ring-shaped operation lines:
1) a110 kv power supply I bus and a 110kv power supply II bus of a power supply side of a transformer substation are connected in parallel through a bus coupler circuit breaker, and at least two main transformers (the main transformers refer to main transformers) are simultaneously put into operation and are respectively connected to different power supply buses in a hanging mode.
2) A power receiving I bus and a power receiving II bus of a load side 110kv of the transformer substation are in parallel and put into operation.
3) Between the power supply side and the load side, a plurality of groups of double circuit lines are hung, or a plurality of groups of combined lines of the double circuit lines and the single circuit lines are hung.
And a branch circuit breaker is respectively arranged on the power supply side and the load side of the two single circuit lines in each group of double circuit lines and is put into operation.
4) The power supply side of each single circuit line of the two single circuit lines is respectively connected with different power supply buses through two parallelly connected isolation disconnecting switches in a hanging mode and is selected to be put into operation; the load sides of the two single circuit lines are respectively connected with different power receiving buses through another isolation disconnecting link and are put into operation.
5) And on the load side, a section breaker is hung between the two single circuit lines.
2. Improvements in or relating to the invention
1) The power side refers to one side of the two transformer substation buses connected by the double circuit lines for providing electric energy, and the load side refers to one side of the two transformer substation buses connected by the double circuit lines for receiving electric energy.
2) The main wiring of the power supply side adopts a double-bus wiring mode.
3) At least two main transformers (such as 1# B and 2# B in 1) on the power supply side are put into operation simultaneously and are respectively connected with different buses.
4) The trip position TWJ-ML of the power side bus bar circuit breaker (the component indicated by ML in figure 1, called bus bar for short) is accessed to the quick ring-opening device by the hard contact point representing the on-off state.
In the quick ring-opening device, when a bus tie breaker at the power supply side is in a split position, the trip position is marked as 1, and TWJ-ML is 1; when the position is closed, the tripping position is marked as 0, and TWJ-ML is equal to 0.
5) The switching-on position of the double-circuit line branch isolation switch at the power supply side is accessed to the quick ring-opening device by a hard contact representing the switching-off and switching-on states.
The switching-on position of the branch isolation switch is represented as: DZ-1G-L, DZ-2G-L, wherein ". L" represents a branch, such as: the position of the m-branch I mother isolation disconnecting link is represented as DZ-1G-mL, and the position of the m-line II mother isolation disconnecting link is represented as DZ-2G-mL. In a quick ring-opening device, DZ-1G-mL is 1, and DZ-2G-mL is 0, which represents that I mother is hung on the branch m; DZ-1G-mL is 0 and DZ-2G-mL is 1, representing m branches with II parent.
6) And a branch m _ knife switch forced soft pressing plate, a branch m _1G knife switch forced soft pressing plate and a branch m _2G knife switch forced soft pressing plate are arranged. When the branch m _ disconnecting link is forced to be put in, the on-off state of the branch m hanging bus is judged through the on-off state of the branch m _1G disconnecting link forcing soft pressing plate and the branch m _2G disconnecting link forcing soft pressing plate.
7) And arranging a hard pressing plate for X-ring annular wiring operation, wherein the hard pressing plate is used for indicating that an X-ring double-circuit line adopts an annular wiring operation mode. And if the double-circuit line branch of a certain ring is overhauled or quits to operate, the ring-shaped wiring operation hard pressing plate corresponding to the ring quits.
8) A 'quick ring-opening' hard pressing plate is arranged, and the hard pressing plate is put into a state that the quick ring-opening device is put into the quick ring-opening function of the method. The quick loop-opening function receives the position of the power supply side bus-coupled circuit breaker, the current of the bus-coupled circuit breaker, the bus voltage and the position of the double-circuit disconnecting switch, and executes a command to cut off the double-circuit branch circuit breaker of the fault side bus after logical judgment is carried out according to the method.
Examples are as follows:
as shown in fig. 1, for an active power supply system with a double bus on the power supply side, a transformer 1# B is hung on a power supply i bus, and a transformer 2# B is hung on a power supply ii bus.
#1 Ring (i.e., first double Loop line):
composed of single branch lines #1L and # 2L.
A power supply side: the single branch line #1L is connected with a power supply I bus to be put into operation through a branch line breaker 1DL, and the single branch line #2L is connected with a power supply II bus to be put into operation through a branch line breaker 2 DL;
and (3) loading side: the single branch line #1L is hung on a power receiving I bus or a power receiving II bus through a branch line breaker 11DL, and the single branch line #2L is hung on a power receiving bus different from the power receiving bus hung on the single branch line #1L through a branch line breaker 12 DL;
a sectionalizer is also connected between the single branch line #1L and the single branch line #2L on the load side.
Loop # 2:
consisting of single legs #3L and # 4L.
A power supply side: the single branch line #3L is connected with a power supply I bus to be put into operation through a branch line breaker 3DL, and the single branch line #4L is connected with a power supply II bus to be put into operation through a branch line breaker 4 DL;
and (3) loading side: the single branch line #3L is hung on a power receiving I bus or a power receiving II bus through a branch line breaker 13DL, and the single branch line #4L is hung on a power receiving bus different from the power receiving bus hung on the single branch line #3L through a branch line breaker 14 DL;
a sectionalizer is also connected between the single branch line #3L and the single branch line #4L on the load side.
Loop # 3:
consisting of single branches #5L and # 6L.
The specific connection mode is the same as before.
The #7L line and the #8L line are single lines for hanging the power supply side and the load side, the #7L line is hung on the power supply I bus, and the #8L line is hung on the power supply II bus.
When the system normally operates, the power supply side bus coupler circuit breaker is closed, the main transformers #1B and #2B are put into operation, the #1 ring double-circuit line annular wiring operation, the #2 ring double-circuit line annular wiring operation, the #3 ring double-circuit line annular wiring operation and the #7L and #8L are put into operation.
The results to be achieved by this example are: if the corresponding line protection is refused due to the fault of the #7L or #8L line, after the trunk switch (parts indicated by 21DL and 22DL in figure 1) is tripped out by the primary transformer backup protection after the primary transformer backup protection first-stage time delay, and before the primary transformer backup protection second-stage time delay, the double-circuit branch line circuit breaker hung on the fault bus is quickly cut off, the power supply path of the normal side bus to the fault point is cut off, and the accident range is prevented from being expanded.
In this example, the method for rapidly releasing the loop of the double-loop operation line comprises the following steps:
firstly, the quick ring-opening device is charged, and the use of the charging in the power industry means that some necessary conditions before action are met. As shown in fig. 2, the logic conditions for "charging" the quick release device are:
(1) a 'quick ring-opening' hard pressing plate is put into the device to enter a quick ring-opening functional working mode;
(2) putting a hard pressing plate in the process of annular wiring operation of a #1 ring, putting a hard pressing plate in the process of annular wiring operation of a #2 ring and putting a hard pressing plate in the process of annular wiring operation of a #3 ring;
(3) the power supply side bus tie breaker is closed, and TWJ-ML is 0;
(4) the bus I of the power supply meets the pressure condition, and the bus II of the power supply meets the pressure condition (the bus pressure condition means that the bus interphase voltage is greater than the bus pressure fixed value).
And (4) satisfying the conditions (1) to (4) for 10 seconds, and finishing the charging of the quick ring-opening device. The purpose of "charging" the quick ring-opening device is to enable the quick ring-opening device to work normally, and is an initial condition for executing the method of the invention, and if the condition is not limited, the quick ring-opening device may not enter a normal working state, so that the purpose of "charging" the quick ring-opening device is a material condition for subsequently cutting off the double-circuit branch line breaker hung on the fault side bus.
The double-circuit branch line breaker for cutting off the bus hung on the fault side is divided into two conditions:
in the first case, as shown in fig. 3, the double line branch breaker logic, which is hooked up to the power i bus, is cut off:
(1) completing the charging of the quick ring-releasing device;
(2) the bus-coupled current reaches the starting condition (the burst variable of two cycles of the bus-coupled current reaches 0.5In, the In refers to the secondary rated value of the CT of the bus-coupled circuit breaker, and the internal part of the starting condition keeps 7S);
(3) quick ring-opening starting and switching-in (any main transformer tripping bus connection point is switched in, and the starting and switching-in mark is kept for 300 ms);
(4) the bus-coupled zero-sequence current meets the positive direction, or does not meet the zero-sequence direction calculation condition and the bus-coupled phase current meets the positive direction (the positive direction of the bus-coupled zero-sequence current means that the bus-coupled zero-sequence current flows into the I bus from the II bus, and the positive direction of the bus-coupled phase current means that the bus-coupled phase current flows into the I bus from the II bus;
(5) the bus-coupled circuit breaker has no current, and the bus-coupled three-phase current is less than 0.05 In;
(6) and the bus re-pressing condition of the power supply I is met (the bus re-pressing condition is met, namely the bus voltages are all smaller than a low-voltage fixed value, or the bus zero-sequence voltage is larger than a zero-sequence voltage fixed value, or the bus negative-sequence voltage is larger than a negative-sequence voltage fixed value).
And (3) when the conditions from (1) to (6) are met and 40ms is continuously met, the quick ring-opening device sends a command of quickly cutting off the I parent branch circuit action, and cut off the #1L, #3L, #5L line breakers 1DL, 3DL and 5DL of the I parent of the hanging power supply.
In the second case, as shown in fig. 4, the double line branch breaker logic, which is hooked up to the supply il, is cut off:
(1) completing the charging of the quick ring-releasing device;
(2) the bus-coupled current reaches the starting condition (the burst variable of two cycles of the bus-coupled current reaches 0.5In, the In refers to the secondary rated value of the CT of the bus-coupled circuit breaker, and the internal part of the starting condition keeps 7S);
(3) quick ring-opening starting and switching-in (any main transformer tripping bus connection point is switched in, and the starting and switching-in mark is kept for 300 ms);
(4) the bus-coupled zero-sequence current meets the reverse direction, or does not meet the zero-sequence direction calculation condition and the bus-coupled phase current meets the reverse direction (the zero-sequence current reverse direction means that the bus-coupled zero-sequence current flows from the I bus to the II bus, and the bus-coupled phase current reverse direction means that the bus-coupled phase current flows from the I bus to the II bus);
(5) the bus-coupled circuit breaker has no current, the bus-coupled three-phase current is less than 0.05In,
(6) and the bus re-pressing condition of the power supply II is met (the bus re-pressing condition is met, namely the bus voltages are all smaller than a low-voltage fixed value, or the bus zero-sequence voltage is larger than a zero-sequence voltage fixed value, or the bus negative-sequence voltage is larger than a negative-sequence voltage fixed value).
When the conditions (1) to (6) are met and 40ms is continuously met, the quick looping-off device sends a command of quickly cutting off the II parent branch circuit action, and cut off the #2L, #4L, #6L line breakers 2DL, 4DL and 6DL of the hooked II parent power supply.
In the example, the ISA-358GL type fast loop release device of Long Yuan Shen relay protection automation Limited company is adopted, the division and combination information of the power supply side bus connection position, the bus connection current, the bus voltage and the position of the double-circuit line disconnecting link is obtained through a connecting structure accessed by a hard contact, after logic judgment is executed by adopting ANSI standard C programming language, the fast loop release device is operated to operate the trip contact of the operation circuit of the plate part, and a command of executing trip is sent to an operating mechanism, as in the embodiment 1,
judging that the charging conditions (1) - (4) are met, continuously meeting for 10 seconds, and completing the recording of charging the quick ring-opening device: charged Rec ().
And (3) judging that the conditions (1) to (6) are met in the first condition, continuously meeting 40ms, and sending a command of 'fast cutting I mother branch action': TripBus01 ().
And the second condition judges that the conditions (1) to (6) are met, the conditions are continuously met for 40ms, and a command of rapidly cutting off the II parent branch is sent out: TripBus02 ().
The method of the invention adopts the purpose of firstly charging the quick ring-opening device, and aims to ensure that the quick ring-opening device enters the initial state for implementing the method of the invention so as to meet the prerequisite condition of cutting off the double-circuit line branch circuit breaker hung on the fault bus, then the quick ring-opening device executes logic according to the information of the bus connection position, the bus connection current, the bus voltage, the double-circuit line disconnecting link position and the like, sends a tripping command, and trips off the double-circuit line branch circuit breaker on the fault side bus, thereby ensuring the normal side bus to continue to operate, preventing the accident range from being expanded, improving the power supply reliability, and providing guarantee for realizing uniform load distribution and reducing the line loss by adopting the double-circuit line ring-shaped connection operation.