CN103840470B - A kind of breaker closing phase control method, Apparatus and system - Google Patents

Abstract

The invention provides a circuit breaker closing phase control method, device and system. The method includes: obtaining the voltage signal of the bus; judging whether the voltage signal reaches the peak value, and if so, controlling the closing of the circuit breaker in the long line; otherwise Circuit breaker does not operate. In order to solve the DC bias problem of the parallel compensation line and improve the reliability of the operation of the circuit breaker equipment.

Description

A circuit breaker closing phase control method, device and system

technical field

The invention relates to the technology of ultra-high voltage long-distance transmission lines, in particular to the phase control closing technology of ultra-high voltage long-distance transmission lines, in particular to a circuit breaker closing phase control method, device and system.

Background technique

Ultra-high voltage long-distance transmission lines often use high-voltage shunt reactors to balance the capacitive reactive power generated by the line, so as to increase the transmission capacity of the line and improve the power frequency overvoltage of the line. The selection of reactor capacity usually depends on the line capacitive current and the reactive power balance of the local system. From the perspective of reactive power compensation, the closer the high resistance capacity is to the capacitive reactive power of the line, the more beneficial it is to improve reactive power balance and overvoltage conditions. But if the difference between the line charging reactive power and the high reactance capacity is too small, when the line is charged from one end, the power frequency component of the line current is very small. Since the current flowing through the reactor cannot change abruptly, a large DC current will be generated during the charging process. When the power frequency component of the current is much smaller than the DC component, the current will flow for a long period of time (hundreds of milliseconds) after the operation of the empty line. The current passing through the circuit breaker has no stable zero-crossing point, which causes the DC bias problem of the empty charging current of the parallel compensation line. If the circuit breaker performs opening operation due to various reasons at this time, the arc may not be extinguished in time after the circuit breaker reaches the position, and the arc burning lasting for hundreds of milliseconds will burn the internal components of the arc extinguishing chamber, deteriorate the SF6 gas, and possibly develop into a larger failure.

Contents of the invention

The invention provides a circuit breaker closing phase control method, device and system to solve the DC bias problem of parallel compensation lines and improve the reliability of circuit breaker equipment operation.

The object of the present invention is to provide a circuit breaker closing phase control method, the method comprising: obtaining the voltage signal of the bus; judging whether the voltage signal reaches a peak value, and if so, controlling the closing of the circuit breaker in the long line, Otherwise the circuit breaker does not operate.

Obtaining the voltage signal of the bus includes: obtaining the ACB three-phase voltage signal of the bus in turn; judging whether the voltage signal of the A phase reaches the peak value, and if so, controlling the closing of the A phase circuit breaker in the long line, and after the closing of the A phase circuit breaker, after 60 ° Control the closing of the C-phase circuit breaker in the long line, and control the closing of the B-phase circuit breaker in the long line after the C-phase circuit breaker is closed.

The circuit breaker closing phase control method includes: obtaining the current mutation signal of the long line; obtaining the conduction time from the initial closing of the circuit breaker to the actual conduction of the circuit according to the current mutation signal, and performing feedback calibration on the circuit breaker according to the conduction time. test.

The object of the present invention is to provide a circuit breaker closing phase control device, which includes: a voltage signal input unit for obtaining the voltage signal of the bus; a phase control unit for judging whether the voltage signal reaches a peak value, and if so, then Send closing control commands to circuit breakers in long lines.

The object of the present invention is to provide a circuit breaker closing phase control system, which includes: a circuit breaker and a circuit breaker closing phase control device; the circuit breaker is connected to the circuit breaker closing phase control device; the circuit breaker closing phase control device The control device includes: a voltage signal input unit, used to obtain the voltage signal of the bus; a phase control unit, used to judge whether the voltage signal reaches the peak value, and if so, send a closing control command to the circuit breaker in the long line; a current input unit, It is used to obtain the current mutation signal of the long line; the feedback verification unit is used to obtain the conduction time from the initial closing of the circuit breaker to the actual conduction of the circuit according to the current mutation signal, and send a feedback calibration to the circuit breaker according to the conduction time. test signal.

The beneficial effects of the present invention are: by adopting the closing phase control technology, the DC current generated by the closing line is suppressed, thereby avoiding the risk of DC bias; when the circuit breaker opens under any conditions after closing the empty line, the The current has a stable zero-crossing point, which ensures the reliable breaking of the circuit breaker and improves the safe operation level of the circuit breaker.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is the flow chart of the circuit breaker closing phase control method of the embodiment of the present invention;

Fig. 2 is the flow chart of the method for controlling the closing phase of a three-phase circuit breaker according to an embodiment of the present invention;

Fig. 3 is the waveform diagram of the relationship between the circuit closing phase and the zero-crossing time of the embodiment of the present invention;

Fig. 4 is the circuit breaker closing time control waveform diagram of the embodiment of the present invention;

5 is a current waveform diagram of a sudden change in current according to an embodiment of the present invention;

6 is a structural block diagram of a circuit breaker closing phase control device according to an embodiment of the present invention;

7 is a structural block diagram of a three-phase circuit breaker closing phase control device according to an embodiment of the present invention;

8 is a schematic circuit diagram of a circuit breaker closing phase control device according to an embodiment of the present invention;

9 is a schematic circuit diagram of a circuit breaker closing phase control system according to an embodiment of the present invention;

Fig. 10 is an application schematic diagram of a circuit breaker closing phase control system according to an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1, the circuit breaker closing phase control method of this embodiment includes: obtaining the voltage signal of the bus (step S101); judging whether the voltage signal reaches the peak value, if so, controlling the closing of the circuit breaker in the long line, if Otherwise, the circuit breaker does not operate (step S102).

As shown in Figure 2, the method for controlling the closing phase of a three-phase circuit breaker in this embodiment specifically includes: sequentially acquiring ACB three-phase voltage signals of the bus (step S201); The phase A circuit breaker in the line is closed, and the phase C circuit breaker in the long line is controlled to close by 60° after the phase A circuit breaker is closed, and the B phase in the long line is controlled to be open by 60° after the phase C circuit breaker is closed switch on (step S202). Acquire the current mutation signal of the long line (step S203); obtain the conduction time from the initial closing of the circuit breaker to the actual conduction of the circuit according to the current mutation signal, and perform feedback verification on the circuit breaker according to the conduction time (step S204) .

In the circuit breaker closing phase control method, the inventors of this case have found through the research on the mechanism and influencing factors of the DC bias of the line with parallel compensation that the magnitude of the DC bias generated by line switching is related to the compensation degree of the shunt reactor, the combined The closing phase of the circuit breaker is related to the configuration of the closing resistance of the circuit breaker, and the phenomenon of DC bias can be effectively suppressed by controlling the closing phase of the circuit breaker when other conditions remain unchanged.

In the case that the circuit breaker has no closing resistance, the magnitude of the DC component of the closing current changes sinusoidally with the closing phase. When the bus voltage at the head end is expressed in sinusoidal form, the closing phase is 0° and 180° (that is, when the bus voltage crosses zero), the DC component generated is the largest, which is equal to the peak value of the AC current flowing through the reactor; the closing phase is 90° And 270° (that is, the bus voltage peak value) when the DC component is zero. Then the zero-crossing time of the current after the circuit breaker is closed is directly related to the closing phase: when the DC component generated by closing is less than the peak value of the remaining AC component of the line at a certain phase, the closing current has a stable zero-crossing point. As shown in Figure 3, the closing phase of a certain line is between -20° to 20° and 160° to 200°; when the closing angle is in other phases, the DC component is greater than the AC component, and the current does not change within a short time after closing. Stable zero crossing. That is, if the closing phase can be controlled so that the three phases are closed separately in one cycle, and the three-phase closing phases are all phases that can quickly cross zero, then the damage caused by the DC bias to the "closing and opening" operation of the circuit breaker can be avoided. risk.

The closing phase control method has the following requirements on the circuit breaker:

1) The closing time is stable. The closing phase control of the circuit breaker is closely related to the mechanical operation stability of the circuit breaker, the time characteristics of the circuit breaker mechanism at different temperatures, the pre-breakdown time characteristics of the circuit breaker, and the operating time of the circuit breaker under different control voltages and different mechanism pressures . The probability distribution and deviation value of the closing time are obtained by testing the mechanical time characteristics of the circuit breaker at room temperature.

Closing time mean μ: $\mathrm{\μ}=\stackrel{\‾}{x}=\mathrm{E.}\left(x\right)=\frac{1}{500}\underset{i=1}{\overset{500}{\mathrm{\Σ}}}{x}_i=63.577\mathrm{ms}.$

Sample variance: ${\mathrm{\σ}}^2=S^2=\frac{1}{500-1}\underset{i=1}{\overset{500}{\mathrm{\Σ}}}{(x_i-\stackrel{\‾}{x})}^2=0.0437\mathrm{ms}.$

Standard deviation σ = 0.209ms.

3σ = 0.209 x 3 = 0.627ms is obtained.

It complies with the requirements of the allowable action deviation 3σ≤±1.5ms stipulated in the CIGRE guidelines of the International Conference on Large Power Grids.

2) The mechanical properties are not affected by the surrounding environment or can be effectively estimated by the environment. Through the matching test of the mechanical characteristics of the circuit breaker under different temperature conditions, the basic test data that the closing time of the mechanical characteristics of the circuit breaker is affected by the environmental temperature factor is obtained. And input it to the phase selection closing device for numerical compensation.

3) The pre-arcing time and arcing time are short. The curve of the reduction rate of insulation strength between fractures is obtained through the RDDS test of the pre-breakdown time of live closing, so as to obtain the pre-breakdown time when closing in different phases. During the phase selection closing operation, the mechanical closing time is subtracted from the pre-breakdown time of the phase closing to determine the optimal closing phase of the phase selection closing.

4) Closing without overshoot. Through the mechanical time characteristic test of the circuit breaker under different control voltages and different hydraulic conditions, the closing time curves under different control voltages and different operating oil pressures are obtained.

As shown in Figure 4, according to the above-mentioned analysis of the mechanism and influencing factors of DC bias, controlling the closing of the circuit breaker when the bus voltage reaches the peak value can minimize the generated DC component. If all three phases are switched on at the positive peak time, the maximum difference between the three-phase switching on will reach about 13.3ms. Aiming at the problem that the closing phase is too large, in this embodiment, the strategy of three-phase closing according to the ACB sequence is adopted, that is, after phase A closes at the peak of positive (or negative) polarity, the phase voltage reaches negative at 60°C. (or positive) polarity peak closing, and then through 60°B phase voltage to reach positive (or negative) polarity peak closing, thus shortening the theoretical out-of-synchronization time of three-phase closing to 6.7ms, while ensuring the suppression of DC bias effectiveness.

As shown in Figure 5, the actual turn-on moment of the loop can be judged by the sudden change of the voltage or current of the line. Because the current of the circuit breaker is always zero before the circuit is turned on, and it is completely free from the interference of adjacent phases, it is beneficial to the realization of the sudden change criterion. Therefore, in this embodiment, the current mutation is used as the basis for judging the actual conduction of the loop, and the corresponding feedback link is set.

As shown in Figure 6, the circuit breaker closing phase control device 100 of this embodiment includes: a voltage signal input unit 101, used to obtain the voltage signal of the bus; a phase control unit 102, used to determine whether the voltage signal reaches the peak value, if it is Then send a closing control command to the circuit breaker in the long line.

As shown in Figure 7, the three-phase circuit breaker closing phase control device 100' of this embodiment includes: a voltage signal input unit 101', which sequentially acquires the ACB three-phase voltage signals of the bus; a phase control unit 102', which judges the Whether the phase A voltage signal reaches the peak value, if so, the phase A circuit breaker in the long line sends a closing control command, and the phase A circuit breaker sends a closing control command to the C phase circuit breaker in the long line after closing 60° , After the C-phase circuit breaker is closed, it sends a closing control command to the B-phase circuit breaker in the long line through 60°. The current signal input unit 103' is used to obtain the current mutation signal of the long line; the feedback verification unit 104' is used to obtain the conduction time from the initial closing of the circuit breaker to the actual conduction of the circuit according to the current mutation signal, And send a feedback verification signal to the circuit breaker according to the conduction time.

As shown in Figure 8, a specific circuit for implementing the circuit breaker closing phase control device of this embodiment includes: a central processing unit (CPU), an AC input part (current signal input and voltage signal input), a transmitter, an expansion board and Power Board. Among them: the AC input part has a three-phase current input terminal, a bus A phase voltage input terminal, a bus B phase voltage input terminal and a bus C phase voltage input. The expansion board has A-phase closing output, B-phase closing output, and C-phase closing output. The power board has a power input (220DC/AC) and a fault alarm and protection action relay signal outlet.

As shown in Figure 9 and Figure 10, the circuit breaker closing phase control system of this embodiment includes: a circuit breaker and a circuit breaker closing phase control device; the circuit breaker is connected to the circuit breaker closing phase control device; The gate phase control device includes: a voltage signal input unit, which is used to obtain the voltage signal of the bus; a phase control unit, which is used to judge whether the voltage signal reaches the peak value, and if so, send a closing control command to the circuit breaker in the long line The current input unit is used to obtain the current mutation signal of the long line; the feedback verification unit is used to obtain the conduction time from the initial closing of the circuit breaker to the actual conduction of the circuit according to the current mutation signal, and Sending a feedback verification signal to the circuit breaker according to the conduction time. The voltage signal input unit sequentially acquires the ACB three-phase voltage signal of the bus; the phase control unit judges whether the A-phase voltage signal reaches the peak value, and if so, the A-phase circuit breaker in the phase-long line sends a closing control command, and the A-phase circuit breaker closes After 60°, send a closing control command to the C-phase circuit breaker in the long line, and after the C-phase circuit breaker is closed, send a closing control command to the B-phase circuit breaker in the long line after 60°.

The application of the closing phase control device of this embodiment greatly reduces the inrush current and overvoltage caused by closing, which is beneficial to the stability of the entire power grid, thereby reducing the construction and maintenance costs of the power system. Due to the application of the closing phase control device, it is possible to cancel the opening and closing resistance of the circuit breaker and related control equipment, thereby greatly simplifying the internal structure of the circuit breaker, improving equipment reliability and reducing production costs. According to statistics, the closing resistor and related control equipment of the circuit breaker account for 8% to 10% of the cost of the entire circuit breaker. Reduce the electrical wear of the circuit breaker contacts during breaking, reduce the possibility of re-ignition of the circuit breaker contacts, and prolong the service life and maintenance cycle of the circuit breaker equipment. For closing capacitor banks or transformers, the application of phase control technology can reduce the inrush current, making the insulation structure design of capacitors or transformers relatively simple, and it is also easier to identify faults for protection. For UHV grid AC systems, the application of closing phase control devices can significantly reduce the insulation requirements of UHV power equipment such as lines, thereby simplifying the design of grid structures and compact lines.

In the present invention, specific examples have been applied to explain the principles and implementation methods of the present invention, and the descriptions of the above examples are only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to this The idea of the invention will have changes in the specific implementation and scope of application. To sum up, the contents of this specification should not be construed as limiting the present invention.

Claims (6)

1. a breaker closing phase control method, is characterized in that, described method comprises:

Obtain the voltage signal of bus;

Whether the voltage signal described in judgement reaches peak value, if it is controls the breaker closing in long transmission line, if otherwise described circuit breaker be failure to actuate;

Obtain the current break signal of described long transmission line;

Obtain the ON time of circuit breaker from the actual conducting to loop of initial combined floodgate according to described current break signal, and according to described ON time, feedback check is carried out to described circuit breaker.

2. breaker closing phase control method according to claim 1, is characterized in that, the voltage signal of described acquisition bus comprises: the ACB three-phase voltage signal obtaining bus successively;

Whether the A phase voltage signal described in judgement reaches peak value, if it is the A phase breaker closing in long transmission line is controlled, control the C phase breaker closing in long transmission line through 60 ° after A phase breaker closing, after C phase breaker closing, control the B phase breaker closing in long transmission line through 60 °.

3. a breaker closing phase control device, is characterized in that, described device comprises:

Voltage signal input unit, for obtaining the voltage signal of bus;

Phase control unit, for judging whether described voltage signal reaches peak value, if it is sends shutting-brake control instruction to the circuit breaker in long transmission line;

Current signal input unit, for obtaining the current break signal of described long transmission line;

Feedback check unit, for obtaining the ON time of circuit breaker from the actual conducting to loop of initial combined floodgate according to described current break signal, and sends feedback check signal according to described ON time to described circuit breaker.

4. breaker closing phase control device according to claim 3, is characterized in that, described voltage signal input unit obtains the ACB three-phase voltage signal of bus successively;

Whether the A phase voltage signal described in described phase control unit judges reaches peak value, if it is the A phase circuit breaker in phase long transmission line sends shutting-brake control instruction, send shutting-brake control instruction through 60 ° to the C phase circuit breaker in long transmission line after A phase breaker closing, after C phase breaker closing, send shutting-brake control instruction through 60 ° to the B phase circuit breaker in long transmission line.

5. a breaker closing phase control system, is characterized in that, described system comprises: circuit breaker and breaker closing phase control device;

Described circuit breaker is connected with breaker closing phase control device;

Described breaker closing phase control device comprises:

Voltage signal input unit, for obtaining the voltage signal of bus;

Phase control unit, for judging whether described voltage signal reaches peak value, if it is sends shutting-brake control instruction to the circuit breaker in long transmission line;

Electric current input unit, for obtaining the current break signal of described long transmission line;

Feedback check unit, for obtaining the ON time of circuit breaker from the actual conducting to loop of initial combined floodgate according to described current break signal, and sends feedback check signal according to described ON time to described circuit breaker.

6. breaker closing phase control system according to claim 5, is characterized in that, described voltage signal input unit obtains the ACB three-phase voltage signal of bus successively;

Whether the A phase voltage signal described in described phase control unit judges reaches peak value, if it is the A phase circuit breaker in phase long transmission line sends shutting-brake control instruction, send shutting-brake control instruction through 60 ° to the C phase circuit breaker in long transmission line after A phase breaker closing, after C phase breaker closing, send shutting-brake control instruction through 60 ° to the B phase circuit breaker in long transmission line.