An electronic phase-shifting PT secondary voltage recovery device and recovery method

Abstract

The present invention discloses an electronic phase-shift PT secondary voltage recovery device, comprising: an AC / DC conversion module, a DC / AC conversion module, a voltage sampling module, a voltage phase-shift module, and a control phase-shift module; the input end of the AC / DC conversion module is connected to an external AC power, and the output end is connected to the input end of the DC / AC conversion module; the output end of the DC / AC conversion module is connected to a load access terminal; the input end of the voltage sampling module is connected to a normal TV voltage, and the output end of the voltage sampling module is connected to the input end of the voltage phase-shift module; the control end of the control phase-shift module is connected to the controlled end of the DC / AC conversion module. The present invention uses the voltage of an undisconnected line as a sample, and uses phase shifting as a control means to first convert an external AC power supply into DC power, and then, by offsetting the phase amount, converts the DC power into an AC power with the same voltage value and different phase as the undisconnected line to simulate the voltage of the disconnected line for collection by an energy meter.

Description

Technical Field

[0001] The present invention relates to the technical field of PT voltage control, and in particular to an electronic phase-shifted PT secondary voltage recovery device and a recovery method. Background Art

[0002] In the high-voltage power distribution device of the power consumption unit, there is usually a high-voltage power metering device, and the high-voltage power metering method adopts the high-supply high-metering method. The metering device of this method is equipped with a high-voltage voltage transformer and a high-voltage current transformer. In the operation of the electric energy metering device, due to the influence of various objective reasons such as system voltage fluctuations and lightning, it is inevitable that the high-voltage fuse of one phase of the voltage transformer will be blown, causing the PT secondary voltage to have a voltage loss fault. Once a fault occurs, professionals should promptly shut down the power supply and restore the accurate operation of the metering device.

[0003] However, in actual situations, once such a fault occurs, the power user often does not have qualified fuse spare parts or cannot shut down the power during production, so the fault cannot be handled in time. Since the voltage loss cannot make the electric energy metering device measure correctly, the power user will lose more money when in production, and it will also cause unnecessary disputes. Therefore, it is particularly important to study a device that can establish or restore the missing PT secondary voltage without power outage. With this device, the metering function of the electric energy metering device can be temporarily restored without delaying the power user's power consumption, and the PT fuse failure problem can be solved by power outage at a planned or agreed time. It is a very convenient and practical voltage recovery device. Summary of the invention

[0004] The present invention provides an electronic phase-shifting PT secondary voltage recovery device and a recovery method to solve the technical problem of PT secondary voltage loss failure caused by high-voltage fuse blowing in the prior art, which leads to energy metering leakage.

[0005] The present invention provides an electronic phase-shift PT secondary voltage recovery device, comprising: an AC / DC conversion module, a DC / AC conversion module, a voltage sampling module, a voltage phase shift module, and a control phase shift module; the input end of the AC / DC conversion module is connected to an external alternating current, and the output end of the AC / DC conversion module is connected to the input end of the DC / AC conversion module; the output end of the DC / AC conversion module is connected to a load access terminal; the input end of the voltage sampling module is connected to a normal TV voltage, and the output end of the voltage sampling module is connected to the input end of the voltage phase shift module; the control end of the control phase shift module is connected to the controlled end of the DC / AC conversion module.

[0006] Furthermore, the voltage phase shifting module includes a tapped transformer, the output end of the voltage sampling module is connected to the primary winding of the tapped transformer, and an adjustable resistor and a capacitor are connected in series between the two ends of the secondary winding of the tapped transformer; the connection point between the tap of the tapped transformer and the adjustable resistor and the capacitor serves as the output end of the voltage phase shifting module.

[0007] Furthermore, the voltage phase shifting module includes a tapped transformer, the output end of the voltage sampling module is connected to the primary winding of the tapped transformer, and an adjustable resistor and an inductor are connected in series between the two ends of the secondary winding of the tapped transformer; the connection point between the tap of the tapped transformer and the adjustable resistor and the inductor serves as the output end of the voltage phase shifting module.

[0008] Furthermore, the electronic phase-shifted PT secondary voltage recovery device also includes a feedback module; the input end of the feedback module is connected to the output end of the DC / AC conversion module, and the output end of the feedback module is connected to the feedback end of the control phase-shift module.

[0009] The present invention also provides a voltage recovery method applicable to an electronic phase-shifted PT secondary voltage recovery device, comprising the following steps:

[0010] Step 1: Connect the electronic phase-shifted PT secondary voltage recovery device before the electric energy meter, connect the voltage sampling module without disconnecting the line, connect the output end of the DC / AC conversion module to the electric energy meter terminal or the secondary phase terminal of the voltage transformer; connect the external AC power to the AC / DC conversion module;

[0011] Step 2: Taking the voltage phase on the undisconnected line as a reference, the voltage phase offset is set by the voltage phase shifting module;

[0012] Step 3: Control the phase shift module to control the DC / AC conversion module to output the phase-shifted voltage signal according to the offset phase amount, and use the phase-shifted voltage signal to simulate the voltage of the disconnected line for collection by the energy meter.

[0013] Furthermore, the specific method of step 2 is: taking the voltage phase on the undisconnected line as a reference, setting the offset phase amount that lags behind the voltage phase on the undisconnected line through the voltage phase shift module, or taking the voltage phase on the undisconnected line as a reference, setting the offset phase amount that leads the voltage phase on the undisconnected line through the voltage phase shift module.

[0014] Furthermore, in step 2, when the three phases connected to the electronic phase-shifting PT secondary voltage recovery device are in a positive phase sequence, the voltage phase on the undisconnected line is used as a reference, and the voltage phase shift module is used to set the offset phase amount that lags behind the voltage phase on the undisconnected line; when the three phases connected to the electronic phase-shifting PT secondary voltage recovery device are in a reverse phase sequence, the voltage phase on the undisconnected line is used as a reference, and the voltage phase shift module is used to set the offset phase amount that leads the voltage phase on the undisconnected line.

[0015] Furthermore, the step 3 also includes a feedback module feeding back the voltage amplitude and voltage phase signal output by the DC / AC conversion module. When the feedback voltage amplitude is less than or greater than the required voltage amplitude, the control phase shift module controls the DC / AC conversion module to increase or decrease the output voltage amplitude; when the feedback voltage phase lags behind or leads the required voltage phase, the control phase shift module controls the DC / AC conversion module to lead or lag the output voltage phase according to the adjustment of the voltage phase shift module.

[0016] Beneficial effects of the present invention:

[0017] The present invention uses the voltage of the undisconnected line as a sample, and uses phase shifting as a control means to first convert the external AC power supply into DC power, and then, by offsetting the phase amount, converts the DC power into AC power with the same voltage value and different phase as the undisconnected line to simulate the voltage of the disconnected line for power meter collection. The present invention can also feedback the amplitude, phase and other changes of the output voltage through the feedback module, so that the output voltage can track the output amount in time and make adjustments, ensuring that the output voltage is consistent with the voltage of the normal phase of the TV, and the phase also meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0019] Figure 1 It is a circuit block diagram of a specific embodiment of the present invention;

[0020] Figure 2 A schematic diagram of circuit connection for accessing the main circuit of a specific embodiment of the present invention;

[0021] Figure 3 It is a schematic diagram of a panel of the device box of the present invention;

[0022] Figure 4 This is a schematic diagram of the AC / DC conversion module circuit of the present invention;

[0023] Figure 5 This is a circuit diagram of a voltage sampling module of the present invention;

[0024] Figure 6A schematic diagram of a circuit for setting a lagging phase for a voltage phase shift module of the present invention;

[0025] Figure 7 A schematic diagram of a circuit for setting an advanced phase for a voltage phase shift module of the present invention;

[0026] Figure 8 This is a schematic diagram of a circuit for controlling a phase shift module according to the present invention;

[0027] Fig. 9 This is a schematic diagram of the DC / AC conversion module circuit of the present invention;

[0028] Fig.10 This is a circuit diagram of the feedback module of the present invention;

[0029] Fig.11 It is a schematic diagram of the lagging phase shift when the positive phase sequence A phase loses voltage in the present invention;

[0030] Fig.12 It is a schematic diagram of the leading phase shift when the reverse phase sequence A phase loses voltage in the present invention;

[0031] Fig.13 It is a schematic diagram of the lagging phase shift when the positive phase sequence B phase loses voltage in the present invention;

[0032] Fig.14 It is a schematic diagram of the leading phase shift when the reverse phase sequence B phase loses voltage in the present invention;

[0033] Fig.15 It is a schematic diagram of the lagging phase shift when the positive phase sequence C phase loses voltage in the present invention;

[0034] Fig.16 It is a schematic diagram of the leading phase shift when the reverse phase sequence C phase loses voltage in the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0036] like Figure 1As shown, an embodiment of the present invention provides an electronic phase-shifted PT secondary voltage recovery device, which is mainly aimed at 10KV customer three-phase three-wire high-voltage metering and a circuit in which the voltage transformer is a v / v wiring method, including: an AC / DC conversion module, a DC / AC conversion module, a voltage sampling module, a voltage phase shift module, a control phase shift module, and a feedback module; the input end of the AC / DC conversion module is connected to an external alternating current, and the output end is connected to the input end of the DC / AC conversion module; the output end of the DC / AC conversion module is connected to an electric energy meter terminal or a secondary phase terminal of a voltage transformer; the input end of the voltage sampling module is connected to a normal TV voltage, and the output end is connected to the input end of the voltage phase shift module; the control end of the control phase shift module is connected to the controlled end of the DC / AC conversion module; the input end of the feedback module is connected to the output end of the DC / AC conversion module, and the output end is connected to the feedback end of the control phase shift module.

[0037] like Figure 3 As shown, the AC / DC conversion module, the DC / AC conversion module, the voltage sampling module, the voltage phase shift module, and the control phase shift module are arranged in the device box 1; the device box is provided with a wiring area 2, a knob area 3, and a display area 4. The wiring area includes a group of external power supply terminals 21, a group of reference voltage terminals 22, and a group of voltage output terminals 23. The external power supply terminal 21 in the wiring area 2 is connected to the input end of the AC / DC conversion module, the reference voltage terminal 22 in the wiring area 2 is connected to the input end of the voltage sampling module, and the voltage output terminal 23 in the wiring area 2 is connected to the output end of the DC / AC conversion module; the display area 4 includes an input voltage display 41 and an output voltage and phase display 42. The input voltage display 41 and the output voltage and phase display 42 are connected to the control phase shift module; the knob area 3 includes a power switch 31, a phase adjustment knob 32, and a voltage adjustment knob 33. The phase adjustment knob 32 and the voltage adjustment knob 33 are connected to the voltage phase shift module. As shown Figure 2 As shown, each item of the main line is connected to the primary side of the voltage transformer PT through a high-voltage fuse, and the secondary side of the voltage transformer PT is connected to the voltage terminal of the electric energy meter DS through the voltage terminal of the combined junction box. The external power supply is connected through the external power supply terminal 21. Taking the melting of the high-voltage fuse FUa as an example, at this time, the voltage terminal XTa of the combined junction box is in a disconnected state, one interface of a group of reference voltage terminals 22 is connected in parallel between the voltage terminal XTb of the combined junction box and the B-phase voltage terminal DSb of the electric energy meter DS, another interface of a group of reference voltage terminals 22 is connected in parallel between the voltage terminal XTc of the combined junction box and the C-phase voltage terminal DSc of the electric energy meter DS, one interface of a group of voltage output terminals 23 is connected in parallel between the voltage terminal XTb of the combined junction box and the B-phase voltage terminal DSb of the electric energy meter DS, and another interface of a group of voltage output terminals 23 is connected in parallel between the voltage terminal XTa of the combined junction box and the A-phase voltage terminal DSa of the electric energy meter DS.

[0038] The working principle of the present invention is as follows:

[0039] External AC power is supplied through Figure 4 The AC / DC conversion module shown in the figure becomes direct current, and the normal voltage of TV passes through Figure 5 The voltage sampling module shown in the figure obtains the voltage phase of the undisconnected line by sampling the voltage across one of the two series resistors, such as Figure 6 , 7 The two voltage phase shift module circuits shown in the figure set the phase offset through the voltage phase shift module, such as Figure 8 The control phase shift module circuit shown is combined with Fig. 9 The DC / AC conversion module circuit composed of enhanced field effect transistors and their peripheral circuits converts direct current into alternating current and performs phase shift. The alternating current simulates the voltage signal missing after a certain high-voltage fuse is blown. The alternating current is directly input into the corresponding terminals of the energy meter to ensure the normal energy collection of the energy meter. In order to improve the accuracy, the following are added: Fig.10 The feedback module circuit shown, which is composed of an operational amplifier and its peripheral circuits, feeds back the voltage amplitude of the output signal to the control phase shift module. The operator can view whether the voltage output by the current DC / AC conversion module meets the requirements through the input voltage display, output voltage and phase display in the display area. When the voltage amplitude output by the DC / AC conversion module is less than or greater than the required voltage, the operator can adjust the voltage amplitude through the voltage adjustment knob, and the control phase shift module will control the DC / AC conversion module to increase or decrease the output voltage amplitude according to the adjustment result; when the voltage phase output by the DC / AC conversion module leads or lags behind the required voltage phase, the operator can adjust the phase through the phase adjustment knob, and the control phase shift module will control the DC / AC conversion module to lag or lead the output voltage phase according to the adjustment result.

[0040] The recovery method of the electronic phase-shifted PT secondary voltage recovery device of the present invention comprises the following steps:

[0041] Step 1: Connect the electronic phase-shifted PT secondary voltage recovery device before the electric energy meter, connect the undisconnected line to the voltage sampling module, and connect the output end of the DC / AC conversion module to the disconnected line; connect the external AC power to the AC / DC conversion module;

[0042] Step 2: Taking the voltage phase on the undisconnected line as a reference, the voltage phase shift module is used to set the offset phase amount that lags behind the voltage phase on the undisconnected line, or taking the voltage phase on the undisconnected line as a reference, the voltage phase shift module is used to set the offset phase amount that leads the voltage phase on the undisconnected line;

[0043] Step 3: The phase shifting module is controlled to control the DC / AC conversion module to output the phase-shifted voltage signal according to the offset phase amount and the feedback signal of the feedback module, and the phase-shifted voltage signal is used to simulate the voltage of the disconnected line for collection by the energy meter.

[0044] The circuits of the voltage phase shift modules corresponding to the phase lag adjustment and phase advance adjustment are different. When the phase lag is adjusted, Figure 6 As shown, the voltage phase shift module includes a tapped transformer, the output end of the voltage sampling module is connected to the primary winding of the tapped transformer, and an adjustable resistor and a capacitor are connected in series between the two ends of the secondary winding of the tapped transformer; the connection point between the tap of the tapped transformer and the adjustable resistor and the capacitor serves as the output end of the voltage phase shift module;

[0045] When the phase advance adjustment is made, Figure 7 As shown, the voltage phase shift module includes a tapped transformer, the output end of the voltage sampling module is connected to the primary winding of the tapped transformer, an adjustable resistor and an inductor are connected in series between the two ends of the secondary winding of the tapped transformer; the connection point between the tap of the tapped transformer and the adjustable resistor and the inductor serves as the output end of the voltage phase shift module.

[0046] When the high-voltage fuse of phase A is blown, the line of phase A input to the energy meter is a disconnected line, and the normal voltage obtained by the energy meter is only U cb , the voltage value is about 100V, U ab No voltage, connect the output voltage terminal to the A and B phases of the energy meter, and connect the B and C phases to the reference voltage terminal. When the voltage phase shift module is in the phase lag adjustment circuit, the connected three phases are in the positive phase sequence, that is, the phases are ABC. At this time, connect U cb The voltage is used as the reference voltage, and the voltage vector that lags behind by 60° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows: Fig.11 As shown in the figure, U ab It is to control the DC according to U cb The alternating current generated by the voltage vector lagging 60° is represented by U ab It returns to normal, making up for the missing A-phase voltage signal; when the voltage phase shift module is in the phase lag adjustment circuit, the three phases connected are in reverse phase sequence, that is, the phase is ACB, at this time, U cb The voltage is used as the reference voltage, and the voltage vector that leads by 60° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows Fig.12 As shown in the figure, U ab It is to control the DC according to U cbThe voltage vector leads by 60° and the alternating current is generated. ab It returns to normal and makes up for the missing A-phase voltage signal.

[0047] When the high-voltage fuse of phase C is blown, the line of phase C of the input energy meter is a disconnected line, and the normal voltage obtained by the energy meter is only U ab , the voltage value is about 100V, U cb No voltage, connect the output voltage terminal to the C and B phases of the energy meter, and connect the A and B phases to the reference voltage terminal. When the voltage phase shift module is in the phase lag adjustment circuit, the connected three phases are in the positive phase sequence, that is, the phases are ABC. At this time, connect U ab The voltage is used as the reference voltage, and the voltage vector that lags behind by 60° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows: Fig.13 As shown in the figure, U cb It is to control the DC according to U ab The alternating current generated by the voltage vector lagging 60° is represented by U cb It returns to normal, making up for the missing C-phase voltage signal; when the voltage phase shift module is in the phase lag adjustment circuit, the three phases connected are in reverse phase sequence, that is, the phase is ACB, at this time, U ab The voltage is used as the reference voltage, and the voltage vector that leads by 60° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows Fig.14 As shown in the figure, U cb It is to control the DC according to U ab The voltage vector leads by 60° and the alternating current is generated. cb Returns to normal and makes up for the missing C-phase voltage signal.

[0048] When the high-voltage fuse of phase B is blown, the line of phase B of the input energy meter is a disconnected line, and the normal voltage obtained by the energy meter is only U ac or U ca , the voltage value is about 100V, U ab , U cb Voltage is only U ac 1 / 2 of the voltage, electric energy meter U ab , U cb The voltage is abnormal. Connect the output voltage terminal to the B phase of the energy meter and the secondary B phase terminal of the voltage transformer, and connect the A and C phases to the reference voltage terminal. When the voltage phase shift module is in the phase lag adjustment circuit, the three phases connected are in the positive phase sequence, that is, the phase is ABC. At this time, connect U acThe voltage is used as the reference voltage, and its voltage vector that lags behind by 90° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows Fig.15 As shown in the figure, U ab , U cb It controls the DC current according to U ac The alternating current generated by the voltage vector lagging 90° is represented by U ab , U cb It returns to normal, making up for the missing B-phase voltage signal; when the voltage phase shift module is in the phase lag adjustment circuit, the three phases connected are in reverse phase sequence, that is, the phase is ACB, at this time, U ca The voltage is used as the reference voltage, and the voltage vector that leads by 90° is used as the offset phase quantity. The DC / AC conversion module is controlled with the offset phase quantity so that the voltage phase of the AC power converted from the input DC power conforms to the offset phase quantity. The result is as follows Fig.16 As shown in the figure, U ab , U cb It controls the DC current according to U ca The voltage vector leads by 90° and generates an alternating current, so the U ab , U cb Return to normal and make up for the missing B-phase voltage signal.

[0049] In the above description, the clockwise rotation of the reference voltage vector is defined as lag, and the counterclockwise rotation of the reference voltage vector is defined as lead.

[0050] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A recovery method for an electronic phase-shifted PT secondary voltage recovery device, wherein: The electronic phase-shift PT secondary voltage recovery device comprises: an AC / DC conversion module, a DC / AC conversion module, a voltage sampling module, a voltage phase shift module, and a control phase shift module; the input end of the AC / DC conversion module is connected to an external alternating current, and the output end of the AC / DC conversion module is connected to the input end of the DC / AC conversion module; the output end of the DC / AC conversion module is connected to a load access terminal; the input end of the voltage sampling module is connected to a normal TV voltage, and the output end of the voltage sampling module is connected to the input end of the voltage phase shift module; the control end of the control phase shift module is connected to the DC / AC conversion module is connected to the controlled end; the voltage phase shifting module includes a tapped transformer, and the output end of the voltage sampling module is connected to the primary winding of the tapped transformer; an adjustable resistor and a capacitor are connected in series between the two ends of the secondary winding of the tapped transformer, and the connection point between the tap of the tapped transformer and the adjustable resistor and the capacitor serves as the output end of the voltage phase shifting module, or an adjustable resistor and an inductor are connected in series between the two ends of the secondary winding of the tapped transformer, and the connection point between the tap of the tapped transformer and the adjustable resistor and the inductor serves as the output end of the voltage phase shifting module, It is characterized in that the recovery method of the electronic phase-shifted PT secondary voltage recovery device comprises the following steps: Step 1: Connect the electronic phase-shifted PT secondary voltage recovery device before the electric energy meter, connect the voltage sampling module without disconnecting the line, connect the output end of the DC / AC conversion module to the electric energy meter terminal or the secondary phase end of the voltage transformer; connect the external AC power to the AC / DC conversion module; Step 2: Based on the voltage phase on the undisconnected line, the voltage phase offset is set by the voltage phase shift module, specifically: When the three phases connected to the electronic phase-shifting PT secondary voltage recovery device are in positive phase sequence, the voltage phase on the undisconnected line is used as a reference, and the voltage phase shift module is used to set the offset phase amount that lags behind the voltage phase on the undisconnected line; when the three phases connected to the electronic phase-shifting PT secondary voltage recovery device are in reverse phase sequence, the voltage phase on the undisconnected line is used as a reference, and the voltage phase shift module is used to set the offset phase amount that leads the voltage phase on the undisconnected line; Step 3: Control the phase shift module to control the DC / AC conversion module to output the phase-shifted voltage signal according to the offset phase amount, and use the phase-shifted voltage signal to simulate the voltage of the disconnected line for collection by the energy meter.

2. The recovery method of the electronic phase-shifted PT secondary voltage recovery device according to claim 1, characterized in that: The electronic phase-shifted PT secondary voltage recovery device further comprises a feedback module; the input end of the feedback module is connected to the output end of the DC / AC conversion module, and the output end of the feedback module is connected to the feedback end of the control phase-shift module.

3. The recovery method of the electronic phase-shifted PT secondary voltage recovery device according to any one of claims 1 or 2, characterized in that: The step 3 also includes the feedback module feeding back the voltage amplitude and voltage phase signal output by the DC / AC conversion module. When the feedback voltage amplitude is less than or greater than the required voltage amplitude, the control phase shift module controls the DC / AC conversion module to increase or decrease the output voltage amplitude; when the feedback voltage phase lags behind or leads the required voltage phase, the control phase shift module controls the DC / AC conversion module to lead or lag the output voltage phase according to the adjustment of the voltage phase shift module.

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