Intelligent measurement and control device and method for direct current traction

Abstract

The application discloses a kind of DC traction inverter control device, including rectifier unit's three-phase current transformer and three-phase bus voltage transformer, bidirectional converter's three-phase current transformer and three-phase bus voltage transformer, DC bus voltage transformer, bidirectional converter device control interface, measurement unit;Rectifier unit's three-phase current transformer and three-phase bus voltage transformer, bidirectional converter's three-phase current transformer and three-phase bus voltage transformer, the output end of DC bus voltage transformer is respectively connected the input end of the measurement unit, the output end of the measurement unit is connected bidirectional converter device control interface.Bidirectional converter device can correctly, accurately judge traction, no-load and feedback working condition, and then control bidirectional converter to carry out mode switching, to eliminate the phenomenon of refusal or malfunction caused by dependence on voltage threshold, avoid train electric brake failure risk, maximum limit use regenerative power, improve economy.

Description

Technical Field

[0001] This invention belongs to the field of traction and regenerative power control technology for DC traction substations in rail transit, specifically relating to an intelligent measurement and control device and method for DC traction substations. Background Technology

[0002] As urban rail transit develops towards higher speeds (120 km / h and above), larger capacity, and more frequent starts and stops, the inherent defects of DC power systems are becoming increasingly prominent, posing a significant bottleneck to the industry's green, safe, and high-quality development. Test statistics show that regenerative braking energy accounts for approximately 30% to 50% of the traction energy consumption of subway trains. How to safely and efficiently utilize this "green energy" has become a core issue that DC power systems cannot avoid.

[0003] Traditional DC traction power supply systems use diode rectifier units, allowing electrical energy to flow unidirectionally from the AC grid to the DC traction network, lacking reverse transmission capability. When a train undergoes regenerative braking, the regenerated electrical energy converted from kinetic energy cannot be fed back to the grid, easily leading to an increase in the DC traction network voltage. Some regenerative energy can only flow within the DC traction network; the remaining portion, unusable by neighboring traction trains, is ultimately consumed as heat through the braking resistor. This not only causes significant energy waste but also exacerbates temperature rise in tunnel environments, increases the burden on the environmental control system, and causes secondary energy consumption.

[0004] To recover this energy, an IGBT-based "inverter regenerative braking energy absorption device (feedback device)" is introduced, which activates the inverter feedback by setting a voltage threshold. This technical approach faces a significant challenge: setting the voltage threshold is difficult. If the threshold is set too high, the feedback device may fail to operate, causing the train's electric braking to fail; if the threshold is set too low, the feedback device may misinterpret the traction condition as a regenerative condition, resulting in circulating current and additional losses.

[0005] Numerous academic papers from various domestic teams confirm that the dilemma of voltage threshold setting is a consensus pain point and a hot topic of academic research in the field of DC power supply. This dilemma is not accidental, but an inevitable result that cannot be avoided by the traditional diode rectifier + feedback device power supply structure after the feedback threshold is artificially set.

[0006] The current national standard system only specifies the "normal voltage range" of DC traction networks, without specifying the specific operating voltage threshold of inverter feedback devices. This threshold is manually set by the design institute or engineering party during the project implementation phase based on the line conditions and then handed over to the equipment manufacturer for implementation, lacking a unified standard and scientific basis.

[0007] To avoid voltage threshold setting and the resulting problems of failure to operate or false operation, Professor Li Qunzhan's team was granted an invention patent ZL201410049210.X, entitled "A DC Traction System Energy Feedback Identification Device". However, during implementation, two new problems were discovered: first, the test resistor R generates a certain amount of energy consumption under normal conditions, resulting in additional energy waste; second, it is difficult to balance energy saving (reducing additional energy consumption) and accuracy in the measurement of the test resistor by the DC current sensor, leading to difficulties in practical application.

[0008] To address the above issues, the inventors applied for invention patent ZL202610724219.9, entitled "An Inverter Measurement and Control Device and Method for DC Traction Substations." In this invention, the inverter feedback device only activates when the feedback condition is determined, and does not activate during traction conditions. The inverter feedback device does not bear the traction load. Currently, in some DC traction substations, the feedback device, in addition to feeding back regenerated energy, also shares the traction load with the rectifier unit. This type of feedback device is also called a bidirectional converter. However, using a voltage threshold to activate the bidirectional converter's feedback and rectification has an inherent problem of inaccurate judgment. It cannot correctly and accurately identify regeneration and traction conditions, causing the device to fail to activate, posing a risk of train electric brake failure, and also causing rectifier malfunction, resulting in additional circulating current and wasted energy.

[0009] Therefore, there is an urgent need for a new technical solution that can correctly and accurately identify traction and regenerative operating conditions from both a theoretical and technical perspective, enabling bidirectional converters to smoothly switch between traction and regenerative operating conditions. This application proposes an intelligent measurement and control device and method for DC traction substations to provide a solution for accurate identification of all operating conditions and precise switching of bidirectional converter operating conditions. Summary of the Invention

[0010] The technical problem to be solved by this invention is to overcome the serious defects of existing DC traction substation inverter feedback devices and bidirectional converters that fail to operate or malfunction when operating based on voltage thresholds, and to ensure that measurement accuracy does not affect the logic judgment of regenerative operation. This invention provides a system solution that can correctly and accurately identify traction, regenerative and no-load operation conditions, accurately feed back regenerative power, and accurately coordinate rectifier units to share the traction load, thereby avoiding the risk of electric brake failure.

[0011] To solve the above-mentioned technical problems, this specification provides one or more embodiments of an intelligent measurement and control device for a DC traction substation, including current interconnects LH1, LH2, LH3, YH1, and YH2 on the AC side of the rectifier unit REC; current interconnects LH4, LH5, LH6, YH3, and YH4 on the AC side of the bidirectional converter INVT; voltage interconnect DYH on the DC bus DB; control interface P of the bidirectional converter INVT; and a measurement unit MC. Current interconnects LH1, LH2, and LH3 are all installed on three phase lines on the primary or secondary side of the rectifier transformer TT1, and voltage interconnects YH1 and YH2 are connected in parallel to the rectifier transformer. Between any two different phase lines on the primary or secondary side of TT1; Current Interchange 4 LH4, Current Interchange 5 LH5, and Current Interchange 6 LH6 are all set between three phase lines on the secondary side of the bidirectional converter transformer TT2; Voltage Interchange 3 YH3 and Voltage Interchange 4 YH4 are all connected in parallel between any two different phase lines on the secondary side of the bidirectional converter transformer TT2; Voltage Interchange 5 DYH is connected in parallel to the DC bus DB; The output terminals of Current Interchange 1 LH1, Current Interchange 2 LH2, Current Interchange 3 LH3, Current Interchange 4 LH4, Current Interchange 5 LH5, Current Interchange 6 LH6, Voltage Interchange 1 YH1, Voltage Interchange 2 YH2, Voltage Interchange 3 YH3, Voltage Interchange 4 YH4, and Voltage Interchange 5 DYH are respectively connected to the input terminal of the calculation unit MC, and the output terminal of the calculation unit MC is connected to the control interface P of the bidirectional converter INVT.

[0012] The rectifier transformer TT1, bidirectional converter transformer TT2, rectifier unit REC, and bidirectional converter INVT are all located in the DC traction substation. The primary side of rectifier transformer TT1 draws power from the three-phase high-voltage bus HB, and the secondary side is connected to the AC side of rectifier unit REC. The primary side of bidirectional converter transformer TT2 draws power from the three-phase high-voltage bus HB, and the secondary side is connected to the AC side of bidirectional converter INVT. The DC sides of rectifier unit REC and bidirectional converter INVT are both connected to the DC bus DB.

[0013] Preferably, the rated voltage U of the DC bus DB N It is 750V or 1500V.

[0014] This specification also provides one or more embodiments of an intelligent measurement and control method for a DC traction substation. The no-load active power loss of the rectifier transformer TT1 is denoted as P. 10 The maximum output of the rectifier unit REC is denoted as S. N1 The maximum output of the bidirectional converter INVT is denoted as S. N2 The steps include:

[0015] S1: The measurement unit MC acquires the current I detected by current interconnection one LH1, current interconnection two LH2, and current interconnection three LH3. a1 I b1 Ic1 The current I detected by the current interconnects LH4, LH5, and LH6 is... a2 I b2 I c2 ; and the voltage U detected by the voltage mutual one YH1 and voltage mutual two YH2 ab1 U bc1 The voltage U detected by the voltage mutual three YH3 and voltage mutual four YH4 ab2 U bc2 The voltage detected by the voltage mutual five DYH ;

[0016] The calculation unit MC is based on the current I. a1 I b1 I c1 I a2 I b2 I c2 and voltage U ab1 U bc1、 U ab2 U bc2 Calculate the active power of the rectifier unit REC. And the active power of the bidirectional converter INVT Among them, active power It is positive during rectification. It is positive during rectification and negative during inversion;

[0017] S2: When the current interconnection one LH1, current interconnection two LH2, and current interconnection three LH3 are all installed on the three phase lines of the secondary side of the rectifier transformer TT1, if there is active power =0, the output of the measurement unit MC sends a command to the control interface P of the bidirectional converter INVT to control the bidirectional converter INVT to perform inversion and accumulate active power. Inverter power E inv If there is active power >0, the output of the measurement unit MC sends a command to the control interface P of the bidirectional converter to control the bidirectional converter INVT to perform rectification, and the target rectification power of the bidirectional converter INVT is... = P sum *S N2 / (S N1 +S N2 );

[0018] When the current interconnects LH1, LH2, and LH3 are all installed on the three phase lines of the primary side of the rectifier transformer TT1, if the active power 0 ≤ ≤P 10The output of the measurement unit MC sends a command to the control interface P of the bidirectional converter INVT to control the bidirectional converter INVT to perform inversion and accumulate active power. Inverter power E inv If there is active power >P 10 The output of the measurement unit MC sends a command to the control interface P of the bidirectional converter to control the bidirectional converter INVT to perform rectification. The target rectification power of the bidirectional converter INVT is... =(P sum - P 10 )*S N2 / (S N1 +S N2 );

[0019] Among them, the active power recorded during rectification by the bidirectional converter INVT is... and The sum of these is the total active power P. sum Total cumulative active power P sum The total rectified power is E sum ;

[0020] S3: Collect inverter electricity E inv Total rectified power E sum The ratio of the two is used to form the content of daily and monthly reports;

[0021] S4: Real-time recording of DC bus voltage The change curve is compared with a preset voltage threshold.

[0022] Working principle of the invention:

[0023] The intelligent measurement and control device of the DC traction substation acquires the three-phase current and voltage on the AC side of the rectifier unit (REC) and the AC side of the bidirectional converter (INVT), and calculates their active power P in real time. rec and P inv Furthermore, by utilizing the characteristic that rectifier units can only transmit active power from the AC side to the DC side, the conduction power supply status of the rectifier unit is determined. Based on whether the rectifier unit is rectifying and its active power, a method for distinguishing the traction, regeneration, and no-load conditions of the DC bus is proposed.

[0024] When the current transformer and voltage transformer are located on the secondary side of rectifier transformer TT1, if P rec A value greater than 0 indicates that the rectifier unit REC is supplying power to the DC bus DB. Corresponding to traction operation, the calculation unit MC controls the bidirectional converter INVT to enter rectification mode, and operates according to the maximum output S of the rectifier unit REC. N1 With the bidirectional converter INVT maximum output S N2 The traction load is shared proportionally; if Prec =0, the rectifier unit REC is not outputting traction power, indicating that the DC bus is under no-load or regenerative operation. The calculation unit MC switches the bidirectional converter INVT to inverter feedback mode, and simultaneously measures the active power. The cumulative inverter feedback power E inv .

[0025] When the current and voltage transformers are located on the primary side of rectifier transformer TT1, the measured P rec No-load active power loss P including rectifier transformer TT1 10 If P rec >P 10 ,Right now A value greater than 0 indicates that the rectifier unit REC is outputting traction power. The measurement unit MC controls the bidirectional converter INVT to enter rectification mode and calculates the power output according to the calculation method after deducting P. 10 The total traction power determines its rectified power target; if 0 ≤ P rec ≤P 10 That is, P df ≤0 indicates that the rectifier unit REC is not outputting traction power, the DC bus is in no-load or regenerative operation, and the calculation unit MC switches the bidirectional converter INVT to inverter feedback mode, while simultaneously measuring the active power. The cumulative inverter feedback power E inv .

[0026] Under traction conditions, the rectified power target of the bidirectional converter INVT is based on S. N1 With S N2 The proportions are determined. Therefore, when the total traction power changes, the load ratio of the rectifier unit REC and the bidirectional converter INVT is matched with their respective maximum output, avoiding overload of one device while insufficient output of the other.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] I. This invention utilizes the inherent characteristic that diode rectifier units can only transmit electrical energy in one direction. It uses the active power of the rectifier unit's REC AC side to characterize whether it supplies power to the DC bus DB, and selects the control mode of the bidirectional converter INVT based on the discrimination result, thus avoiding failure to operate or false operation caused by voltage threshold.

[0029] Second, under traction conditions, the present invention enables the rectifier unit REC and the bidirectional converter INVT to bear the traction load according to their respective maximum output ratio through the active power PI controller. Under no-load or regenerative conditions, the regenerative power of the traction network is utilized to the maximum extent correctly and accurately. The same device takes into account traction power distribution, no-load operation and regenerative voltage stabilization feedback.

[0030] Third, this invention eliminates the need for a test resistor in series on the DC side, thus avoiding additional energy consumption caused by the test resistor. By detecting the three-phase current on the AC side of the rectifier unit REC through current interconnects LH1, LH2, and LH3, and combining the AC voltage detected by voltage interconnects YH1 and YH2, the active power is calculated. This avoids the problem of balancing measurement accuracy and additional losses in wide-range DC current detection, improving the reliability of operating condition judgment and engineering practicality.

[0031] IV. This invention is compatible with both secondary-side and primary-side detection methods for the rectifier transformer TT1; during primary-side detection, the no-load active power loss P is deducted. 10 This avoids the impact of transformer no-load losses on operating condition assessment. Simultaneously, by recording electricity consumption and DC bus voltage curves, the effectiveness of the original scheme's regenerative energy utilization and the correctness of the device's operating status can be quantitatively evaluated.

[0032] V. This invention is applicable not only to newly built DC traction substations, but also to the retrofitting of inverter feedback devices in existing DC traction substations. Attached Figure Description

[0033] Figure 1 The overall structural block diagram of the intelligent measurement and control device for DC traction in this invention is shown when the AC side current and voltage mutual detection units of the rectifier unit REC are set on the primary side of the rectifier transformer TT1.

[0034] Figure 2 The overall structural block diagram of the intelligent measurement and control device for DC traction in this invention is shown when the current and voltage detection units are set on the secondary side of the rectifier transformer TT1.

[0035] Figure 3 The calculation unit MC calculates the active power P based on the AC side current and voltage of the rectifier unit REC. rec and reactive power Q rec A schematic diagram.

[0036] Figure 4 The calculation unit MC calculates the active power P based on the AC side current and voltage of the bidirectional converter INVT. inv and reactive power Q inv A schematic diagram. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are only for explaining this invention and do not constitute a limitation on the scope of protection of this invention.

[0038] This specification provides one or more embodiments of an intelligent measurement and control device for a DC traction substation, such as... Figure 1 or Figure 2 As shown.

[0039] The DC traction substation includes a three-phase high-voltage busbar HB, rectifier transformer TT1, bidirectional converter transformer TT2, rectifier unit REC, bidirectional converter INVT, and DC busbar DB. The primary side of rectifier transformer TT1 is connected to the three-phase high-voltage busbar HB, and the secondary side is connected to the AC side of rectifier unit REC. The primary side of bidirectional converter transformer TT2 is connected to the three-phase high-voltage busbar HB, and the secondary side is connected to the AC side of bidirectional converter INVT. The DC sides of rectifier unit REC and bidirectional converter INVT are both connected to the DC busbar DB. The rated voltage U of the DC busbar DB is... N It can be 750 V or 1500 V.

[0040] like Figure 1 As shown, current interconnects LH1, LH2, and LH3 are respectively installed on the three phase lines of the primary side of rectifier transformer TT1. Voltage interconnects YH1 and YH2 are respectively connected in parallel between any two different phase lines of the primary side, or, as shown... Figure 2 As shown, current interconnects LH1, LH2, and LH3 are respectively installed on the three phase lines of the secondary side of rectifier transformer TT1. Voltage interconnects YH1 and YH2 are connected in parallel between any two different phase lines of the secondary side to obtain the three-phase current and line voltage of the rectifier unit's REC AC side. Current interconnects LH4, LH5, and LH6 are respectively installed on the three phase lines of the secondary side of bidirectional converter transformer TT2. Voltage interconnects YH3 and YH4 are connected in parallel between any two different phase lines of the secondary side to obtain the three-phase current and line voltage of the bidirectional converter's INVT AC side. Voltage interconnect DYH is connected in parallel to the DC bus DB to obtain the DC bus voltage U. DB .

[0041] The aforementioned current and voltage detection signals are input to the calculation unit MC. The calculation unit MC can be implemented by a controller with sampling, coordinate transformation, power calculation, logic judgment, PI operation, data storage and communication functions. Its output terminal outputs rectification mode command, inverter feedback mode command and power target value through the control interface P of the bidirectional converter INVT.

[0042] In this embodiment, the measurement unit MC collects the three-phase current I on the AC side of the rectifier unit REC. a1 I b1 I c1 and line voltage U ab1 U bc1 Collect the three-phase current I on the AC side of the bidirectional converter INVT. a2 I b2 I c2 and line voltage U ab2 U bc2And collect DC bus voltage U DB Calculate the active power P of the rectifier unit REC based on the collected current and voltage. rec The active power P of the bidirectional converter INVT inv The active power P of the rectifier unit REC rec The active power P of the bidirectional converter INVT inv The sum of these is denoted as the total active power P. sum .

[0043] In this invention, the maximum output of the rectifier unit REC is denoted as S. N1 The maximum output of the bidirectional converter INVT is denoted as S. N2 Let the rated capacity of the rectifier unit REC be S1, then its maximum output... Where k1 is the overload factor of the rectifier unit REC; assuming the rated capacity of the bidirectional converter INVT is S2, then its maximum output... Where k2 is the overload factor of the bidirectional converter INVT. The specific values ​​of k1 and k2 can be determined according to the allowable overload capacity and duration of the equipment, for example, taking... ,Pick .

[0044] In this embodiment, P rec P represents the active power on the AC side of the rectifier unit REC. inv The INVT value represents the active power on the AC side of the bidirectional converter, with the rectification direction (transferring electrical energy from the AC side to the DC side) as positive and the inversion direction (transferring electrical energy from the DC side to the AC side) as negative; U DB P represents the DC bus voltage. 10 This represents the no-load active power loss of rectifier transformer TT1.

[0045] In this embodiment, as Figure 2 As shown, when current transformers LH1, LH2, and LH3, as well as voltage transformers YH1 and YH2, are installed on the secondary side of rectifier transformer TT1: if P rec If the value is greater than 0, it is determined that the rectifier unit REC is in rectification mode, the DC bus DB is in traction mode, and the bidirectional converter INVT is controlled to enter rectification mode, and its rectification power is set to the target value. If P rec If the value is 0, it is determined that the rectifier unit REC is not outputting active power to the DC bus DB, and the DC bus is in no-load or regenerative operation. The bidirectional converter INVT is controlled to switch to inverter feedback mode, and the feedback power does not exceed the maximum output of the bidirectional converter.

[0046] In this embodiment, as Figure 1As shown, when current interconnects LH1, LH2, and LH3, as well as voltage interconnects YH1 and YH2, are installed on the primary side of rectifier transformer TT1, the measured active power includes the no-load active power loss P of rectifier transformer TT1. 10 Therefore, with As a discriminant power reflecting the actual state of the rectifier unit's REC: if P df If the value is greater than 0, it is determined that the rectifier unit REC is in rectification mode, the DC bus DB is in traction mode, and the bidirectional converter INVT is controlled to enter rectification mode, and its rectification power is set to the target value. If P df ≤0, that is, 0≤P rec ≤P 10 If the rectifier unit REC fails to output active power to the DC bus DB, the DC bus is in no-load or regenerative operation. The bidirectional converter INVT is then switched to inverter feedback mode, with the feedback power not exceeding the maximum output of the bidirectional converter.

[0047] The calculation unit MC processes the total rectified electrical energy E of the DC bus under traction conditions. sum Inverter power E under regenerative operating conditions inv Generate data containing E according to a preset statistical period. sum E inv Daily and monthly reports on the ratio of the two; simultaneously, real-time recording of DC bus voltage U. DB The curve of change of U, and can be used to... DB The voltage is compared with a preset voltage threshold. This voltage threshold is used for status monitoring, alarms, or protection, or as a basis for verifying voltage control parameters.

[0048] To accommodate sensor errors, sampling noise, and power fluctuations, P can be adjusted during engineering implementation. rec =0 is understood as P rec It is within the preset zero-power tolerance band, and can be on both sides of the zero-power boundary, or at P 10 Hysteresis ranges and continuous judgment times are set on both sides of the boundary; the control mode is switched only after the judgment result has been continuously reached for a preset time, so as to avoid frequent switching of the bidirectional converter INVT near the judgment boundary.

[0049] In this embodiment, refer to Figure 3 The measurement unit MC acquires the three-phase current I of the rectifier unit. a1 I b1 I c1 and line voltage U ab1 U bc1 Then, calculate the active power of the rectifier unit. and reactive power .

[0050] Specifically, current I a1 I b1 I c1 enter Figure 3 After being processed by the Clarke module shown, the current I is converted into a two-phase stationary coordinate system. alfa1 I beta1 Voltage U ab1 U bc1 enter Figure 3 After the phase-locked loop shown, the phase angle Theta1 and voltage component U of the AC side voltage of the rectifier unit are obtained. d1 U q1 Current I alfa1 I beta1 And the phase angle Theta1 is then input. Figure 3 The Park module shown, after coordinate transformation, yields the active current I. d1 and reactive current I q1 Voltage component U d1 U q1 and current component I d1 I q1 The power is input into the power calculation module to obtain the active power of the rectifier unit. and reactive power .

[0051] Reference Figure 4 The measurement unit MC obtains the three-phase current I of the bidirectional converter. a2 I b2 I c2 and line voltage U ab2 U bc2 Then, calculate the active power of the bidirectional converter. and reactive power .

[0052] Specifically, current I a2 I b2 I c2 enter Figure 4 After being processed by the Clarke module shown, the current I is converted into a two-phase stationary coordinate system. alfa2 I beta2 Voltage U ab2 U bc2 enter Figure 4 After the phase-locked loop shown, the AC side voltage phase angle Theta2 and voltage component U of the bidirectional converter are obtained. d2 U q2 Current I alfa2 I beta2 And the phase angle Theta2 is then input. Figure 4 The Park module shown, after coordinate transformation, yields the active current I.d2 and reactive current I q2 Voltage component U d2 U q2 and current component I d2 I q2 The active power of the bidirectional converter is obtained by inputting it into the power calculation module. and reactive power .

[0053] The power calculation module can calculate active power according to the three-phase instantaneous power theory. For example, the active power of the rectifier unit REC can be expressed as... The active power of the bidirectional converter INVT can be expressed as: When the phase-locked loop aligns the d-axis with the AC-side voltage vector, U q1 and U q2 Approaching zero, the active power is mainly determined by the product of the d-axis voltage component and the d-axis current component.

[0054] Total rectified power E sum By measuring P under traction conditions sum Obtained by time integration; Inverter energy E inv By analyzing P under inverter operating conditions inv The absolute value is obtained by integrating over time. The measurement unit MC stores E according to a daily, monthly, or other preset period. sum E inv and E inv With E sum The ratio is used to evaluate the amount of regenerated electricity recovered and the energy utilization of DC traction substations.

[0055] The measurement unit MC also records U in chronological order. DB This forms a DC bus voltage variation curve. The preset voltage threshold is generally set empirically to 1700V, used in existing schemes to drive the bidirectional converter's inverter. It can also preset operation monitoring thresholds, alarm thresholds, and protection thresholds to detect DC bus overvoltage, undervoltage, or abnormal fluctuations. The basic distinction between traction and regenerative operating conditions remains based on P... rec Or deduct P 10 P after df Based on.

[0056] In this embodiment, P is referred to as rec =0 or P df =0 represents the ideal state. In practical devices, the power tolerance ε can be set according to the accuracy of the current transformer, voltage transformer, and sampling circuit. P When detecting secondary edges, |P rec |≤ε P Considered P rec =0, P is set during primary edge detection. rec ≤P10 +ε P Considered P df ≤0; You can also set the continuous judgment time, hysteresis and low-pass filter to suppress mode jitter caused by noise and instantaneous power fluctuations.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent measurement and control device for a DC traction substation, characterized in that: This includes the following components installed on the AC side of the rectifier unit REC: Current Interchange 1 LH1, Current Interchange 2 LH2, Current Interchange 3 LH3, Voltage Interchange 1 YH1, Voltage Interchange 2 YH2; Current Interchange 4 LH4, Current Interchange 5 LH5, Current Interchange 6 LH6, Voltage Interchange 3 YH3, Voltage Interchange 4 YH4; Voltage Interchange 5 DYH installed on the DC bus DB; Control interface P of the bidirectional converter INVT; and Measurement unit MC. The current interconnects LH1, LH2, and LH3 are all installed on the three phase lines of the primary or secondary side of the rectifier transformer TT1, and the voltage interconnects YH1 and YH2 are connected in parallel between any two different phase lines of the primary or secondary side of the rectifier transformer TT1. The current interconnects LH4, LH5, and LH6 are all installed on the three phase lines of the secondary side of the bidirectional converter transformer TT2, and the voltage interconnects YH3 and YH4 are connected in parallel between any two different phase lines of the secondary side of the bidirectional converter transformer TT2. The voltage interconnection 5DYH is connected in parallel to the DC bus DB; The output terminals of the current converters LH1, LH2, LH3, LH4, LH5, and LH6, and the voltage converters YH1, YH2, YH3, YH4, and DYH are respectively connected to the input terminal of the measurement unit MC. The output terminal of the measurement unit MC is connected to the control interface P of the bidirectional converter INVT. in, The rectifier transformer TT1, bidirectional converter transformer TT2, rectifier unit REC, and bidirectional converter INVT are all located in the DC traction substation. The primary side of the rectifier transformer TT1 draws power from the three-phase high-voltage bus HB, and the secondary side is connected to the AC side of the rectifier unit REC. The primary side of the bidirectional converter transformer TT2 draws power from the three-phase high-voltage bus HB, and the secondary side is connected to the AC side of the bidirectional converter INVT. The DC sides of the rectifier unit REC and the bidirectional converter INVT are both connected to the DC bus DB.

2. The intelligent measurement and control device for a DC traction substation according to claim 1, characterized in that: The rated voltage U of the DC bus DB N It is 750V or 1500V.

3. A method for intelligent measurement and control of a DC traction substation, applied to the intelligent measurement and control device for a DC traction substation as described in any one of claims 1-2, characterized in that: The no-load active power loss of the rectifier transformer TT1 is denoted as P. 10 The maximum output of the rectifier unit REC is denoted as S. N1 The maximum output of the bidirectional converter INVT is denoted as S. N2 The steps include: S1: The measurement unit MC acquires the current I detected by current interconnection one LH1, current interconnection two LH2, and current interconnection three LH3. a1 I b1 I c1 The current I detected by the current interconnects LH4, LH5, and LH6 is... a2 I b2 I c2 ; and the voltage U detected by the voltage mutual one YH1 and voltage mutual two YH2 ab1 U bc1 The voltage U detected by the voltage mutual three YH3 and voltage mutual four YH4 ab2 U bc2 The voltage detected by the voltage mutual five DYH ; The calculation unit MC is based on the current I. a1 I b1 I c1 I a2 I b2 I c2 and voltage U ab1 U bc1 U ab2 U bc2 Calculate the active power of the rectifier unit REC. And the active power of the bidirectional converter INVT Among them, active power It is positive during rectification. It is positive during rectification and negative during inversion; S2: When the current interconnection one LH1, current interconnection two LH2, and current interconnection three LH3 are all installed on the three phase lines of the secondary side of the rectifier transformer TT1, if there is active power =0, the output of the measurement unit MC sends a command to the control interface P of the bidirectional converter INVT to control the bidirectional converter INVT to perform inversion and accumulate active power. Inverter power E inv If there is active power >0, the output of the measurement unit MC sends a command to the control interface P of the bidirectional converter to control the bidirectional converter INVT to perform rectification, and the target rectification power of the bidirectional converter INVT is... = P sum *S N2 / (S N1 +S N2 ); When the current interconnects LH1, LH2, and LH3 are all installed on the three phase lines of the primary side of the rectifier transformer TT1, if the active power 0 ≤ ≤P 10 The output of the measurement unit MC sends a command to the control interface P of the bidirectional converter INVT to control the bidirectional converter INVT to perform inversion and accumulate active power. Inverter power E inv If there is active power >P 10 The output of the measurement unit MC sends a command to the control interface P of the bidirectional converter to control the bidirectional converter INVT to perform rectification. The target rectification power of the bidirectional converter INVT is... =(P sum -P 10 )*S N2 / (S N1 +S N2 ); Among them, the active power recorded during rectification by the bidirectional converter INVT is... and The sum of these is the total active power P. sum Total cumulative active power P sum The total rectified power is E sum ; S3: Collect inverter electricity E inv Total rectified power E sum The ratio between the two forms the content of daily and monthly reports; S4: Real-time recording of DC bus voltage The change curve is compared with a preset voltage threshold.

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