CN107579510A - A method for suppressing excitation inrush current of a train vehicle-mounted transformer and a combined circuit breaker system - Google Patents

Abstract

The invention discloses a kind of train-installed transformer excitation flow suppressing method and combination circuit breaker system.This method and system have the function of suppressing mobile transformer excitation surge current.Its structure includes control loop and main circuit two parts, and control loop includes controller, voltage sensor, current sensor etc.；Main circuit includes solid circuit breaker, mechanical chopper etc..The present invention suppresses train-installed transformer excitation flow using phase selection control strategy, i.e., in combination circuit breaker separating brake moment, according to magnetic flux and mutual relation of electric voltage calculating remanent magnetism and records；In moment of closing a floodgate next time, breaker closing phase angle is calculated by remanent magnetism and its attenuation coefficient, its calculating principle is the stable state magnetic flux and transformer remanent magnetism zero deflection for making combined floodgate moment, so as to reach the purpose for suppressing excitation surge current.The present invention also proposes a kind of new circuit breaker system topology, increases solid circuit breaker module in main circuit, had both improved response speed and in turn ensure that the pressure-resistant flow-resistant capacity of circuit breaker system.

Description

A method for suppressing excitation inrush current of a train vehicle-mounted transformer and a combined circuit breaker system

technical field

The invention relates to a circuit breaker control system with the function of suppressing excitation inrush current and an implementation method, belonging to the technical field of circuit breakers.

Background technique

As a switching device that can close the circuit and carry the inrush current, the circuit breaker is widely used in the train traction drive control system.

It is necessary to use the circuit breaker to complete the circuit shut-off operation immediately before the train stops or passes the phase. When the circuit breaker is opened, the air is ionized and becomes a conductor due to the voltage exceeding the tolerance of the air to generate an arc. The arc generally bypasses the insulator and generates along the surface of the insulator, thus causing damage to the insulator. For example, the high temperature of the arc will melt or crack the insulator, thereby causing damage to the safety of people, life and property.

When the train starts or the circuit breaker needs to be used to complete the circuit closing operation immediately after the phase is over, when the circuit breaker is closed, due to the sudden voltage change on the primary side of the transformer, the traction transformer will be oversaturated, thereby generating a very large excitation inrush current, excitation The magnitude of the inrush current is generally more than five times the rated current, which will have a very strong impact on the high-speed train, and then cause the relay to malfunction.

The present invention proposes a method for suppressing the inrush current of a train vehicle-mounted transformer and a combined circuit breaker system on the basis of in-depth research on the causes and hazards of electric arcs and inrush currents. The impact of arc and excitation inrush on the traction drive system can prevent the protection relay from malfunctioning. When shutting down the circuit, first use the PLL phase-locked loop circuit to lock the phase of the fundamental wave current of the catenary, and shut down the circuit when the current crosses zero, which can effectively eliminate the phenomenon of arcing. When closing the circuit, first use the PLL phase-locked loop circuit to lock the fundamental wave voltage phase of the catenary, and then determine the closing time according to the closing phase angle preset by the system. The selection standard of the closing phase angle is to ensure that the closing bias is zero , to suppress on-board transformer saturation. The invention can effectively eliminate arcing and traction transformer excitation inrush current, reduce relay malfunction and reduce the damage of excitation inrush current.

Contents of the invention

Aiming at the problems existing in the prior art, the object of the present invention is to provide a method for suppressing the inrush current of a train on-board transformer and a combined circuit breaker system. The purpose is to reduce the impact on the traction drive system.

In order to achieve the above object, the present invention proposes a method for suppressing the inrush current of a transformer on-board a train and a combined circuit breaker system. Its structural composition includes two parts: a main circuit and a control circuit. etc.; the control circuit includes a controller, a voltage sensor, a current sensor, etc.

A method for suppressing the excitation inrush current of a train vehicle-mounted transformer and a combined circuit breaker system proposed by the present invention, the circuit breaker closing phase angle control method is as follows:

The invention adopts a phase-selection closing control strategy to suppress the excitation inrush current of the vehicle-mounted traction transformer. The specific setting process is as follows:

The main parameters of the control process are set as follows:

The opening phase angle of the circuit breaker is α;

Phase angle β of circuit breaker closing again;

Remanence Φ _res ;

Bias Φ _p ;

Steady-state magnetic flux Φ _s ;

Remanence attenuation coefficient k ₁ ;

The whole control process can be divided into two steps: Step 1: the residual magnetism calculation process after the circuit breaker is disconnected; Step 2: the closing phase angle setting process when the circuit breaker is closed again.

Step 1: Remanence Calculation Process

The relationship between the opening phase angle α and the instantaneous voltage u ₁ when the circuit breaker is disconnected is

The residual magnetism Φ _res after the circuit breaker is disconnected is

Among them, k ₁ is the remanence attenuation coefficient, k ₁ changes with the temperature, humidity and other conditions in the environment where the transformer is located, and its value is set according to the length of the opening and closing interval, and the variation range is 0-1.

Step 2: Closing angle setting process

The steady-state magnetic flux Φ _s and closing phase angle β at the moment the circuit breaker closes again are

Considering that the magnetic flux cannot be transient

Φ _res = Φ _p + Φ _s (4)

Substitute Φ _res and Φ _s into equation (4) to get equation (5)

In order to make the on-board transformer unsaturated, the switching bias needs to be zero, that is, as shown in equation (6)

Φp ₌ 0 (6)

According to formula (6), it can be obtained that the closing phase angle of the circuit breaker needs to satisfy:

β=arccos(k ₁ cosα) (7)

The invention proposes a method for suppressing inrush current of a transformer on-board a train and a combined circuit breaker system. The specific implementation process includes the following two stages: stage 1: the stage of starting the phase of the train; stage 2: the stage of ending the stage of the phase of the train. The specific operation process is as follows:

Stage 1: The stage of train over-phase separation and start-up

After the EMU receives the over-phase start signal, the circuit breaker opening and closing operation process is as follows:

Step 1: When the system receives the over-phase split start signal, it first removes the load by adjusting the converter;

Step 2: Then close the solid-state circuit breaker after confirming that the load is removed;

Step 3: Disconnect the mechanical circuit breaker under the premise of ensuring that the solid-state circuit breaker module is completely closed. During the disconnection process of the mechanical circuit breaker, the voltage across the mechanical circuit breaker is always zero, so the mechanical circuit breaker will not be disconnected during the disconnection process. Arc discharge phenomenon occurs;

Step 4: When the current phase detection module detects the zero-crossing point of the current phase, the solid-state circuit breaker is disconnected, and the controller records the phase α of the voltage waveform at the time when the solid-state circuit breaker is disconnected to calculate the remanence Φ _res of the on-board transformer.

Stage 2: The end stage of the train passing phase

After the EMU receives the end signal of the over-phase separation, the circuit breaker opening and closing operation process is as follows:

Step 1: After receiving the over-phase end signal, close the solid-state circuit breaker module when the phase of the voltage waveform detected by the voltage transformer is the same as the initial closing phase angle preset by the system, and the preset closing initial phase angle is based on the traction The transformer residual magnetism and bias magnetism are set according to the principle of complementarity, so that the closing bias magnetism and residual magnetism are exactly complementary when the switch is closed according to the preset closing initial phase angle after setting;

Step 2: Close the mechanical circuit breaker after confirming that the solid state circuit breaker is completely closed. During the closing process of the mechanical circuit breaker, since the voltage at both ends of the mechanical circuit breaker is zero, the mechanical circuit breaker will not appear arcing during the closing process;

Step 3: Open the solid-state circuit breaker after confirming that the mechanical circuit breaker is fully closed;

Step 4: After the solid-state circuit breaker is completely disconnected, adjust the converter to make the traction motor run, and the on-board transformer of the EMU starts to run with load.

detailed description

A specific implementation of a method for suppressing inrush current of a train-mounted transformer and a combined circuit breaker system according to the present invention will be given below in conjunction with the accompanying drawings, but the implementation of the present invention is not limited to the following embodiments.

Fig. 1 is a system structure diagram of a method for suppressing inrush current of a train vehicle-mounted transformer and a combined circuit breaker system provided by the present invention. Its structural composition includes two parts: a main circuit and a control circuit. The main circuit includes a solid-state circuit breaker module, Mechanical circuit breakers, etc.; control circuits include controllers, voltage sensors, current sensors, etc.

Fig. 2 is a schematic diagram of the method for suppressing the inrush current of the on-board transformer of the train and the algorithm setting process of the phase selection and closing control strategy of the combined circuit breaker system provided by the present invention. The invention adopts a phase-selection closing control strategy to suppress the excitation inrush current of the vehicle-mounted traction transformer. The specific setting process is as follows:

The main parameters of the control process are set as follows:

The opening phase angle of the circuit breaker is α;

Phase angle β of circuit breaker closing again;

Remanence Φ _res ;

Bias Φ _p ;

Steady-state magnetic flux Φ _s ;

Remanence attenuation coefficient k ₁ ;

The whole control process can be divided into two steps: Step 1: the residual magnetism calculation process after the circuit breaker is disconnected; Step 2: the closing phase angle setting process when the circuit breaker is closed again.

Step 1: Remanence Calculation Process

The relationship between the opening phase angle α and the instantaneous voltage u ₁ when the circuit breaker is disconnected is

The residual magnetism Φ _res after the circuit breaker is disconnected is

Among them, k ₁ is the remanence attenuation coefficient, k ₁ changes with the temperature, humidity and other conditions in the environment where the transformer is located, and its value is set according to the length of the opening and closing interval, and the variation range is 0-1.

Step 2: Closing angle setting process

The steady-state magnetic flux Φ _s and closing phase angle β at the moment the circuit breaker closes again are

Considering that the magnetic flux cannot be transient

Φ _res = Φ _p + Φ _s (4)

Substitute Φ _res and Φ _s into equation (4) to get equation (5)

In order to make the on-board transformer unsaturated, the switching bias needs to be zero, that is, as shown in equation (6)

Φp ₌ 0 (6)

According to formula (6), it can be obtained that the closing phase angle of the circuit breaker needs to satisfy:

β=arccos(k ₁ cosα) (7)

Therefore, in order to ensure that the on-board transformer has no excitation inrush current, the closing phase angle needs to satisfy: β=arccos(k ₁ cosα).

Fig. 3 is a kind of train on-board transformer excitation inrush suppression method proposed by the present invention and combined circuit breaker opening and closing timing diagram in the train over-phase start process in the combined circuit breaker system, and Fig. 4 is a kind of train on-board transformer excitation proposed by the present invention Inrush current suppression method and combined circuit breaker opening and closing timing diagram in the process of train over-phase separation in the combined circuit breaker system. The method for suppressing the inrush current of the on-board transformer of the train and the combined circuit breaker system proposed by the present invention can be divided into the following two stages: stage 1: the stage of starting the phase of the train; stage 2: the stage of ending the stage of the phase of the train.

Stage 1: The stage of train over-phase separation and start-up

In this process, the timing diagram of the opening and closing process of the combined circuit breaker is shown in Figure 3. After the EMU receives the over-phase start signal, the opening and closing operation process of the combined circuit breaker is as follows:

Step 1: When the system receives the over-phase start signal at time t ₀ , it first removes the load by adjusting the converter within the time period of T ₀ ;

Step 2: Then close the solid-state circuit breaker at time _t1 after confirming that the load is removed;

Step 3: On the premise of ensuring that the solid-state circuit breaker module is completely closed, disconnect the mechanical circuit breaker at time _t2 . During the process of disconnecting the mechanical circuit breaker, the voltage at both ends of the mechanical circuit breaker is always zero, so the mechanical circuit breaker is disconnected. There will be no arc discharge phenomenon during the opening process;

Step 4: When the current phase detection module detects the zero-crossing point of the current phase, disconnect the solid-state circuit breaker at time _t3 , and at the same time, the controller records the phase α of the voltage waveform at the time when the solid-state circuit breaker is disconnected to calculate the residual magnetism Φ _res of the vehicle-mounted transformer .

Phase 2: The end of the train passing phase

The time sequence diagram of the opening and closing process of the combined circuit breaker in this process is shown in Figure 4. After the EMU receives the end signal of the over-phase separation, the circuit breaker opening and closing operation process is as follows:

Step 1: After the system receives the over-phase end signal at time t4, the solid _- state circuit breaker module is closed when the phase of the voltage waveform detected by the voltage transformer is the same as the initial closing phase angle preset by the system. At this time, the time is t ₅ .

Step 2: Close the mechanical circuit breaker after confirming that the solid-state circuit breaker is completely closed. The time at this time is counted as t ₆ . During the closing process of the mechanical circuit breaker, the voltage at both ends of the mechanical circuit breaker is zero, and the mechanical circuit breaker does not close during the closing process. There will be arcing phenomenon;

Step 3: disconnect the solid-state circuit breaker after it is determined that the mechanical circuit breaker is fully closed, and the moment is t ₇ ;

Step 4: After the solid-state circuit breaker is completely disconnected, adjust the converter to make the traction motor run, and the on-board transformer of the EMU starts to run with load.

Description of drawings

Figure 1: Structure diagram of combined circuit breaker system

Figure 2: Schematic diagram of phase selection closing control strategy algorithm setting

Figure 3: Sequence Diagram of Circuit Breaker Operation in Opening Process

Figure 4: Sequence diagram of circuit breaker operation during closing process.

Claims (5)

1. a kind of train-installed transformer excitation flow suppressing method and combination circuit breaker system, it is characterised in that：A kind of train Mobile transformer excitation surge current suppressing method：The present invention suppresses on-board traction transformer excitation using phase selection control strategy and gushed Stream；The specific control process of phase selection control strategy shutting-brake control strategy is as follows：

If control process major parameter is as follows：

It is α that breaker, which opens a sluice gate phase angle,；

Breaker switching-on phase angle beta again；

Remanent magnetism Φ_res；

Magnetic bias Φ_b；

Stable state magnetic flux Φ_s；

Remanent magnetism attenuation coefficient k₁；

Whole control process can be divided into two steps：Step 1：Calculation of residual flux process after breaker disconnection；Step 2：Again Switching-on phase angle tuning process during secondary combined floodgate；

Step 1：Calculation of residual flux process

The breaker disconnection moment opens a sluice gate phase angle [alpha] and instantaneous voltage u₁Relation be

<mrow> <msub> <mi>u</mi> <mn>1</mn> </msub> <mo>=</mo> <msqrt> <mn>2</mn> </msqrt> <mi>U</mi> <mi> </mi> <mi>s</mi> <mi>i</mi> <mi>n</mi> <mi>&amp;alpha;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

Wherein U is contact net voltage effective value；

Remanent magnetism Φ after breaker disconnection_resFor

<mrow> <msub> <mi>&amp;Phi;</mi> <mrow> <mi>r</mi> <mi>e</mi> <mi>s</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>k</mi> <mn>1</mn> </msub> <mo>&amp;CenterDot;</mo> <mfrac> <mn>1</mn> <msub> <mi>N</mi> <mn>1</mn> </msub> </mfrac> <mo>&amp;Integral;</mo> <msub> <mi>u</mi> <mn>1</mn> </msub> <mi>d</mi> <mi>t</mi> <mo>=</mo> <mo>-</mo> <mfrac> <mrow> <msqrt> <mn>2</mn> </msqrt> <msub> <mi>Uk</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>N</mi> <mn>1</mn> </msub> <mi>&amp;omega;</mi> </mrow> </mfrac> <mi>c</mi> <mi>o</mi> <mi>s</mi> <mi>&amp;alpha;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

Wherein, k₁For remanent magnetism attenuation coefficient, k₁Next conjunction is arrived with the temperature in transformer local environment, humidity and after opening a sluice gate The conditions such as the time interval of lock point change, and its numerical value is adjusted, excursion 0-1 according to switching interval length；

N₁For the mobile transformer primary side number of turn；ω is tractive power supply system contact net angular frequency；

Step 2：Switching angle tuning process

Breaker closes the stable state magnetic flux Φ of moment again_sRelation with switching-on phase angle beta is

<mrow> <msub> <mi>&amp;Phi;</mi> <mi>s</mi> </msub> <mo>=</mo> <mo>-</mo> <mfrac> <mrow> <msqrt> <mn>2</mn> </msqrt> <mi>U</mi> </mrow> <mrow> <msub> <mi>N</mi> <mn>1</mn> </msub> <mi>&amp;omega;</mi> </mrow> </mfrac> <mi>c</mi> <mi>o</mi> <mi>s</mi> <mi>&amp;beta;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow>

Consider that magnetic flux is unable to transition, moment of closing a floodgate meets formula (4)

Φ_res=Φ_b+Φ_s (4)

By Φ_res、Φ_sFormula (5) can be obtained by substituting into equation (4)

<mrow> <msub> <mi>&amp;Phi;</mi> <mi>b</mi> </msub> <mo>=</mo> <mfrac> <msub> <mi>U</mi> <mi>m</mi> </msub> <mrow> <msub> <mi>N</mi> <mn>1</mn> </msub> <mi>&amp;omega;</mi> </mrow> </mfrac> <mi>c</mi> <mi>o</mi> <mi>s</mi> <mi>&amp;beta;</mi> <mo>-</mo> <mfrac> <mrow> <msub> <mi>U</mi> <mi>m</mi> </msub> <msub> <mi>k</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>N</mi> <mn>1</mn> </msub> <mi>&amp;omega;</mi> </mrow> </mfrac> <mi>c</mi> <mi>o</mi> <mi>s</mi> <mi>&amp;alpha;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>5</mn> <mo>)</mo> </mrow> </mrow>

In order that mobile transformer is unsaturated, it is necessary to magnetic bias of closing a floodgate is zero, namely as shown in formula (6)

Φ_b=0 (6)

According to formula (6), can obtain breaker closing phase angle needs to meet formula (7)：

β=arccos (k₁cosα) (7)

So when switching-on phase angle is adjusted as β=arccos (k₁Cos α) when can effectively suppress train and cross split-phase stage vehicle-mounted variable pressure Device device excitation surge current.

2. a kind of train-installed transformer excitation flow suppressing method and combination circuit breaker system, it is characterised in that：It is a kind of new Combination circuit breaker system：The system is provided with control loop and main circuit two parts；Control loop includes controller, mutual induction of voltage Device, current transformer etc.；Voltage transformer, current transformer are respectively used for measuring the voltage of breaker and pantograph link position (referring to neutral point), electric current；Main circuit includes solid circuit breaker, mechanical chopper etc., and mechanical chopper is breaking with solid-state first Device is in parallel, is then series between pantograph and tractive transformer.

3. a kind of train-installed transformer excitation flow suppressing method and combination circuit breaker system, it is characterised in that：Combination open circuit Device system moving process includes two stages：Stage one：It's split-phase startup stage pasts train；Stage two：Train crosses split-phase and terminates rank The section stage；Comprise the following steps that：

Stage one：It's split-phase startup stage pasts train

After EMUs received split-phase enabling signal, breaker switching action process is as follows：

The first step：After system received split-phase enabling signal, first by adjusting current transformer excision load；

Second step：Then confirm that load closes solid circuit breaker after being removed；

3rd step：Mechanical chopper is disconnected on the premise of solid circuit breaker module closure completely is ensured, mechanical chopper is disconnected Because mechanical chopper both end voltage is always zero during opening, put so mechanical chopper disconnection process is not in arcing Electrical phenomena；

4th step：Solid circuit breaker, while controller are disconnected when current phase detection module detects current phase zero crossing Record solid circuit breaker disconnects the phase α of moment voltage waveform calculating mobile transformer remanent magnetism Φ_res；

Stage two：It's the split-phase ending phase stage pasts train

After EMUs received split-phase end signal, breaker switching action process is as follows：

The first step：After split-phase end signal was received, the voltage waveform phase and system detected in voltage transformer is pre- If combined floodgate initial phase angle be mutually closed at solid circuit breaker module, preset combined floodgate initial phase angle according to tractive transformer remanent magnetism and magnetic bias Principle of complementarity is adjusted, and combined floodgate magnetic bias and remanent magnetism are just complementary when making to close a floodgate by the default combined floodgate initial phase angle after adjusting；

Second step：Mechanical chopper is closed after it is determined that solid circuit breaker closes completely, in the process of mechanical chopper closure In because mechanical chopper both end voltage is zero, mechanical chopper is not in phenomenon of arc discharge in closing course；

3rd step：Solid circuit breaker is disconnected after it is determined that mechanical chopper closes completely；

4th step：Regulation current transformer operates traction electric machine after solid circuit breaker is fully disconnected, EMUs mobile transformer Start run with load.

4. a kind of train-installed transformer excitation flow suppressing method according to claim 3 and combination circuit breaker system, It is characterized in that：After EMUs received split-phase enabling signal, breaker switching action process is as follows：

The first step：After system received split-phase enabling signal, first by adjusting current transformer excision load；

Second step：Then confirm that load closes solid circuit breaker after being removed；

3rd step：Mechanical chopper is disconnected on the premise of solid circuit breaker module closure completely is ensured, mechanical chopper is disconnected Because mechanical chopper both end voltage is always zero during opening, put so mechanical chopper disconnection process is not in arcing Electrical phenomena；

4th step：Solid circuit breaker, while controller are disconnected when current phase detection module detects current phase zero crossing Record solid circuit breaker disconnects the phase α of moment voltage waveform calculating mobile transformer remanent magnetism Φ_res。

5. a kind of train-installed transformer excitation flow suppressing method according to claim 3 and combination circuit breaker system, It is characterized in that：After EMUs received split-phase end signal, breaker switching action process is as follows：

The first step：After split-phase end signal was received, the voltage waveform phase and system detected in voltage transformer is pre- If combined floodgate initial phase angle be mutually closed at solid circuit breaker module, preset combined floodgate initial phase angle according to tractive transformer remanent magnetism and magnetic bias Principle of complementarity is adjusted, and combined floodgate magnetic bias and remanent magnetism are just complementary when making to close a floodgate by the default combined floodgate initial phase angle after adjusting；

Second step：Mechanical chopper is closed after it is determined that solid circuit breaker closes completely, in the process of mechanical chopper closure In because mechanical chopper both end voltage is zero, mechanical chopper is not in phenomenon of arc discharge in closing course；

3rd step：Solid circuit breaker is disconnected after it is determined that mechanical chopper closes completely；

4th step：Regulation current transformer operates traction electric machine after solid circuit breaker is fully disconnected, EMUs mobile transformer Start run with load.