CN101969006B - Method for improving converted current switching capability of ultra-high voltage alternating current open isolating switch - Google Patents

Abstract

The invention belongs to the technical field of ultra-high voltage power transmission, in particular to a method for improving the converted current switching capability of an ultra-high voltage open alternating current isolating switch. Auxiliary circuits are added on a main contact to switch converted current, and isolating switches are used to guide the operation of electric poles, so that the converted current switching capability of the isolating switches can be greatly improved, and the use requirements for connecting the isolating switches in parallel can be met. Thus, by using the method, the converted current switching capability is greatly improved, the requirements for connecting the isolating switches in parallel are easily met, the influence of electric arcs is almost completely eliminated, the operation and the control of the isolating switches are greatly simplified, the cost is lowered and the reliability is improved.

Description

Method for Improving Switching Current Switching Ability of UHV AC Open Disconnector

technical field

The invention belongs to the technical field of UHV power transmission, and in particular relates to a method for improving the switching current switching capability of an UHV open-type AC isolating switch.

Background technique

In order to improve the transmission capacity of UHV transmission lines and improve system stability, it is necessary to install UHV series compensation devices on the line. Parallel isolating switches are used to switch the operation mode of series compensation devices. They are important operating equipment and usually use open AC isolating switch. Parallel isolating switches for UHV series compensation require switching current switching capability to meet switching current 6300A and switching voltage 6000V. According to the current standard, the maximum parameters of switching current switching capacity of conventional isolating switches are 1600A switching current and 400V switching voltage, which cannot directly meet the needs of parallel disconnecting switches. It is necessary to find ways to improve the switching current switching capacity.

The conventional method to improve the opening and closing ability of the switching current of the disconnector is to increase the arc extinguishing ability by elongating the arc, and to reduce the harm of arc ablation by using the arc contact made of arc ablation-resistant material to improve the switching current opening and closing ability. Due to the limited combined capacity, it is difficult to meet the high switching current switching requirements of parallel disconnectors.

Technical disadvantages of conventional methods for improving switching current switching capabilities of isolating switches:

The arc is extinguished by elongating the air arc, the breaking capacity is very limited, and it is greatly affected by the environmental conditions;

●Severe open air arc will be generated, and its ablation and diffusion will seriously affect the safe operation of switchgear and its surrounding equipment.

●The opening and closing ability is limited, and it can only meet the highest parameters stipulated in the existing standards: switching current 1600A, switching voltage 400V, which cannot meet the switching current switching requirements of parallel isolating switches with switching current 6300A and switching voltage 6000V.

The invention proposes a new method for improving the opening and closing ability of the isolating switch switching current, that is, by installing an auxiliary circuit on the main contact to open and close the switching current, and using the main conductive rod of the isolating switch to operate, the switching capacity of the isolating switch can be greatly improved. Switching current switching capability to meet the use requirements of parallel isolating switches.

The method proposed by the present invention for improving the switching capacity of the isolating switch to switch current has no similar technical solutions before.

Contents of the invention

The invention proposes a new method for improving the opening and closing ability of the isolating switch switching current, that is, by installing an auxiliary circuit on the main contact to open and close the switching current, and using the main conductive rod of the isolating switch to operate, the switching capacity of the isolating switch can be greatly improved. Switching current switching capability to meet the use requirements of parallel isolating switches.

A method of improving the switching current switching capability of the UHV AC open-type isolating switch of the present invention is characterized in that

By adding an auxiliary circuit on the main contact to open and close the switching current, and using the main conductive rod of the isolation switch to operate, the switching current switching capacity of the isolation switch can be greatly improved;

Include the following steps:

1) Closing process of isolating switch

(1) Before the isolating switch is closed, the main contact is in the off state, the auxiliary contact is in the off state, and the vacuum circuit breaker is in the open state; both the main circuit and the auxiliary circuit are in the off state, and there is no current in the circuit;

(2) In the first transient process of the closing process of the isolating switch, the auxiliary contact has been connected, the vacuum circuit breaker is in the opening state, and the auxiliary circuit is not conducting; the main contact is in the open state, and the main The loop is not conducting; there is no current in the circuit;

(3) In the second transient process of the isolating switch closing process, the auxiliary contact is in the closed state, the vacuum circuit breaker starts to close, and completes the closing of the current of 8000A and below at a voltage of 12kv and below. At this time, the entire The auxiliary circuit is connected; the main contact is disconnected, and the main circuit is not conducted. The current in the circuit flows through the auxiliary circuit;

(4) In the third transient process during the closing process of the isolating switch, the auxiliary contact is in the closed state, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is connected; since the auxiliary circuit is conductive, the main contact The head is connected under the condition of almost no pre-breakdown, which can ensure that the main contact is not burned or slightly burned, and then the main circuit is turned on; the current in the circuit flows in parallel through the main circuit and the auxiliary circuit;

(5) In the final state during the closing process of the isolating switch, the auxiliary contact is disconnected, the vacuum circuit breaker is still in the closing state, and the entire auxiliary circuit is disconnected; the main contact is in the closed state, and the main circuit is turned on. The current in the circuit flows through the main circuit; so far, the isolating switch has completed the closing process and is in the closing state;

2) Isolation switch breaking process

(1) In the initial state during the disconnection process of the disconnector, the auxiliary contact is in the off state, the vacuum circuit breaker is in the closing state, and the entire auxiliary circuit is disconnected; the main contact is in the on state, and the main circuit is turned on; the circuit The current in the main circuit flows through;

(2) In the first transient process of the isolating switch breaking process, the auxiliary contact is connected, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is connected; the main contact is in the connected state, and the main circuit conducts Pass. The current in the circuit flows in parallel through the main circuit and the auxiliary circuit;

(3) In the second transient process of the isolating switch breaking process, the auxiliary contact is in the closed state, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is turned on. Since the auxiliary circuit is turned on, the main contacts are disconnected under the condition of almost no recovery voltage, which reduces or even avoids the arcing of the main contacts, thereby ensuring that the main contacts are not burned or slightly burned; The current flows through the auxiliary circuit;

(4) In the third transient process of the isolating switch breaking process, the auxiliary contact is in the closed state, the vacuum circuit breaker starts to open, breaks the current of 8000A and below and bears the recovery voltage of 12kv and below, at this time the auxiliary The circuit is disconnected; the main contact is disconnected, and the main circuit is not conducting. No current flows through the entire circuit;

(5) In the final state of the isolating switch breaking process, the auxiliary contact is disconnected, the vacuum circuit breaker is in the opening state, the main contact is in the disconnected state, the main circuit and the auxiliary circuit are both in the disconnected state, and there is no current; so far, the isolating switch has completed the breaking process and is in the opening state;

3) Operation of the auxiliary circuit

During the operation of the isolating switch, the operating mechanism of the isolating switch will operate the main conductive rod. During the operation of the main conductive rod, the auxiliary circuit can be driven to operate, so as to realize the operation by the isolating switch operating mechanism. The mechanical position and structure ensure the auxiliary circuit and the main circuit. timing of actions.

The technical advantages of the method for improving the switching current switching capability of the isolating switch proposed by the present invention are as follows:

(1) The switching capacity of switching current mainly depends on the vacuum circuit breaker in the auxiliary circuit. The switching capacity of switching current can be very high, which can easily meet the requirements of parallel isolating switches;

(2) The arc is sealed inside the vacuum interrupter and will not affect the equipment outside the vacuum interrupter;

(3) The vacuum circuit breaker is operated by the main conductive pole of the isolation switch, the operation and control of the vacuum circuit breaker are greatly simplified, the cost is reduced, and the reliability is improved.

The present invention creatively solves the technical shortcomings of conventional methods for improving the switching current switching capability of isolating switches, and can easily meet the high switching voltage and large switching current switching capability requirements of parallel isolating switches, and is simple and reliable, easy to implement, and saves energy. It has very high technical and economic value and application prospect.

Description of drawings

In order to make the content of the present invention more clearly understood, and to facilitate the description of specific embodiments, the accompanying drawings relevant to the present invention are described below as follows:

Fig. 1 is a schematic diagram of the circuit structure of the present invention.

2-6 are detailed diagrams showing five steps of the disconnector closing process, respectively.

7-11 are detailed diagrams showing five steps in the disconnecting process of the disconnector, respectively.

Detailed ways

Explanation of related technical terms

Series compensation (referred to as "series compensation"): A technology that uses capacitor banks connected in series in the line to offset part of the line inductance to reduce the total line impedance, which can greatly improve line transmission capacity and system stability.

Isolating switch: When in the opening position, there is an insulation distance between the contacts that meets the specified requirements and an obvious disconnection mark; when in the closing position, it can carry the current under normal circuit conditions and abnormal conditions within the specified time (such as short circuit) current switching devices.

Note: When the circuit current is "very small", or when the voltage between the two terminals of each pole of the disconnector has no significant change before and after closing and breaking, the disconnector has the ability to close and break the circuit.

Parallel isolation switch for series compensation device: it is connected in series in the transmission line and connected in parallel with the series compensation device, and is used to switch the isolation switch of the series compensation device.

Opening and closing conversion current: when the load is transferred from the transmission line to the series compensation device or from the series compensation device to the transmission line, the opening and closing operation of the disconnector under load conditions.

The technical principle of the technical scheme of the present invention:

●Install an auxiliary circuit consisting of auxiliary contacts and vacuum circuit breakers on the contacts of the isolating switch, use the main conductive rod of the isolating switch to operate, and realize the following operation sequence through the cooperation of mechanical position and structure:

When the isolating switch is closed, the main conductive rod moves - the auxiliary contact closes - the vacuum circuit breaker closes - the main contact closes;

●When the isolating switch is disconnected, the main conductive rod moves - the main contact breaks - the vacuum circuit breaker breaks - the auxiliary contact breaks;

The technical scheme of the present invention elaborates:

As shown in Figure 1, branch 1 is an auxiliary circuit proposed by this scheme, and the auxiliary circuit includes auxiliary contacts and vacuum circuit breakers. Branch 2 is the main circuit, and the main circuit includes main contacts. This program is to install an auxiliary circuit to improve the ability of switching current switching. The specific process is as follows:

1) Closing process of the isolating switch (see Figure 2-6)

(1) Figure 2 shows the state of each fracture before the isolating switch is closed. At this time, the main contact is in the open state, the auxiliary contact is in the open state, and the vacuum circuit breaker is in the open state. Both the main circuit and the auxiliary circuit are disconnected, and there is no current in the circuit.

(2) Figure 3 shows the first transient process during the closing process of the isolating switch. At this time, the auxiliary contact has been connected, the vacuum circuit breaker is in the opening state, and the auxiliary circuit is not conducting. The main contact is disconnected, the main circuit is not conducting, and there is no current in the circuit.

(3) Figure 4 shows the second transient process during the closing process of the isolating switch. At this time, the auxiliary contact is in the closed state, the vacuum circuit breaker starts to close, and the closing of the current of 8000A and below at a voltage of 12kV and below is completed. At this point the entire auxiliary circuit is connected. The main contact is disconnected, and the main circuit is not conducting. The current in the circuit flows through the auxiliary loop.

(4) Figure 5 shows the third transient process during the closing process of the isolating switch. At this time, the auxiliary contact is in the closed state, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is connected. Since the auxiliary circuit is conducting, the main contact is connected under the condition of almost no pre-breakdown, which can ensure that the main contact is not burned or slightly burned, and then the main circuit is turned on. The current in the circuit flows in parallel through the main circuit and the auxiliary circuit.

(5) Figure 6 shows the final state during the closing process of the isolating switch. At this time, the auxiliary contact is disconnected, the vacuum circuit breaker is still in the closed state, and the entire auxiliary circuit is disconnected. The main contacts are closed and the main circuit is turned on. The current in the circuit flows through the main circuit. So far, the isolating switch has completed the closing process and is in the closing state.

2) Isolation switch breaking process (see Figure 7-11)

(1) Figure 7 shows the initial state during the disconnection process of the disconnector. At this time, the auxiliary contact is in the disconnected state, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is disconnected. The main contact is in the connected state, and the main circuit is turned on. The current in the circuit flows through the main loop.

(2) Figure 8 shows the first transient process in the disconnecting process of the isolating switch. At this time, the auxiliary contact is connected, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is connected. The main contact is in the connected state, and the main circuit is turned on. The current in the circuit flows in parallel through the main circuit and the auxiliary circuit.

(3) Figure 9 shows the second transient process during the opening and closing process of the isolating switch. At this time, the auxiliary contact is in the closed state, the vacuum circuit breaker is in the closed state, and the entire auxiliary circuit is turned on. Since the auxiliary circuit is turned on, the main contacts are disconnected under the condition of almost no recovery voltage, reducing or even avoiding the arcing of the main contacts, thereby ensuring that the main contacts are not burned or slightly burned. The current in the circuit flows through the auxiliary loop.

(4) Figure 10 shows the third transient process in the opening process of the isolating switch. At this time, the auxiliary contact is in the closed state, and the vacuum circuit breaker starts to open, breaking the current of 8000A and below and bearing the recovery voltage of 12kV and below. At this time, the auxiliary circuit is disconnected. The main contact is disconnected, and the main circuit is not conducting. No current flows through the entire circuit.

(5) Figure 11 shows the final state of the isolating switch during the breaking process. At this time, the auxiliary contact is disconnected, the vacuum circuit breaker is in the opening state, the main contact is in the disconnected state, and both the main circuit and the auxiliary circuit are in the disconnected state. , there is no current in the circuit. So far, the isolating switch has completed the breaking process and is in the opening state.

3) Operation of the auxiliary circuit

During the operation of the isolating switch, the operating mechanism of the isolating switch will operate the main conductive rod, and the auxiliary circuit can be driven to operate during the operation of the main conductive rod, so as to realize the operation of the isolating switch operating mechanism, the auxiliary circuit and the main circuit guaranteed by the mechanical position and structure. The action sequence coordination of the circuit greatly simplifies the operation and control of the isolating switch, improves the reliability and reduces the cost.

To sum up, by adding an auxiliary circuit and using the main conductive rod to operate, the switching current switching capacity of the UHV open isolating switch can be greatly improved to meet the switching current switching requirements of the parallel disconnecting switch for UHV series compensation.

The invention has been described above in the context of particular embodiments, but those skilled in the art will also appreciate the numerous possibilities of variants and alternative embodiments, for example by combining and/or varying features of individual embodiments. Therefore, it is understood that such modifications and alternative embodiments are to be considered as included in the present invention, the scope of which is limited only by the appended patent claims and their equivalents.

Claims (1)

1. a method that improves converted current switching capability of ultra-high voltage alternating current open isolating switch, is characterized in that

By install subsidiary loop folding switching current additional on main contact, and utilize the operation of isolated switch main conducting rod, can increase substantially the switching current folding ability of isolating switch;

Comprise the following steps:

1) isolating switch closes process

(1) before isolating switch closes, main contact is off-state, and auxiliary contact is off-state, and vacuum circuit-breaker is minute

The lock state; Major loop and subsidiary loop are all off-states, there is no electric current in circuit;

(2) at isolating switch, close in first transient process in process, auxiliary contact is connected, and vacuum circuit-breaker is in gate-dividing state, and subsidiary loop does not have conducting; Main contact is off-state, and major loop does not have conducting; There is no electric current in circuit;

(3) at isolating switch, close in second transient process in process, auxiliary contact is closure state, and vacuum circuit-breaker starts to close a floodgate, and completes closing of the following electric current of 8000A under the following voltage of 12kv, now whole subsidiary loop connection; Main contact is off-state, and major loop does not have conducting, and the electric current in circuit flows through by subsidiary loop;

(4) at isolating switch, close in the 3rd transient process in process, auxiliary contact is closure state, and vacuum circuit-breaker is "on" position, and whole subsidiary loop is connected; Because subsidiary loop is conducting, main contact is connected under the condition that almost there is no prebreakdown, can guarantee that main contact is not burnt or slight scaling loss, major loop conducting immediately; Electric current in circuit flows through by major loop and subsidiary loop parallel connection;

(5) close the final state in process at isolating switch, auxiliary contact disconnects, and vacuum circuit-breaker is still "on" position, and whole subsidiary loop disconnects; Main contact is closure state, the major loop conducting, and the electric current in circuit flows through by major loop; So far, isolating switch has completed the process of closing, in "on" position;

2) isolating switch interrupting process

(1) initial condition in the isolating switch interrupting process, auxiliary contact is off-state, and vacuum circuit-breaker is "on" position, and whole subsidiary loop disconnects; Main contact is on-state, the major loop conducting; Electric current in circuit flows through by major loop;

(2) in first transient process in the isolating switch interrupting process, auxiliary contact is connected, and vacuum circuit-breaker is "on" position, and whole subsidiary loop is connected; Main contact is on-state, the major loop conducting, and the electric current in circuit flows through by major loop and subsidiary loop parallel connection;

(3) in second transient process in the isolating switch interrupting process, auxiliary contact is closure state, vacuum circuit-breaker is "on" position, whole subsidiary loop conducting, because subsidiary loop is conducting, main contact disconnects under the condition that almost there is no recovery voltage, reduces even to have avoided main contact generation arcing, and then guarantees that main contact is not burnt or slight scaling loss; Electric current in circuit flows through by subsidiary loop;

(4) in the 3rd transient process in the isolating switch interrupting process, auxiliary contact is closure state, and vacuum circuit-breaker starts separating brake, cut-offs the following electric current of 8000A and bears the following recovery voltage of 12kv, and now subsidiary loop disconnects; Main contact is off-state, not conducting of major loop, and whole circuit does not have electric current to flow through;

(5) final state in the isolating switch interrupting process, auxiliary contact disconnects, and vacuum circuit-breaker is gate-dividing state, and main contact is off-state, and major loop and subsidiary loop are all off-states, there is no electric current in circuit; So far, isolating switch has completed interrupting process, in gate-dividing state;

3) operation of subsidiary loop

In the isolator operation process, the isolating switch operating mechanism can operate leading electric pole action, can drive the subsidiary loop operation in leading electric pole course of action, thereby realize by the operation of isolating switch operating mechanism, guaranteed that by mechanical location and structure the action sequence of subsidiary loop and major loop coordinates.

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