Real-time monitoring method and system for direct-current resistance of transformer

Abstract

The invention provides a transformer DC resistance real-time monitoring method and system, and the method comprises the steps: collecting voltage and current signals at the primary side and secondary side of a transformer in real time, and calculating the current effective value and active power value of each period of the primary side and secondary side of the transformer, and the power difference value of the two sides; and according to the power difference value and the current effective value of the primary side and the secondary side of the transformer and in combination with the no-load loss of the transformer, the stray loss of the transformer and the historical operation condition, performing estimation calculation on the direct-current resistance of the transformer to obtain a real-time direct-current resistance estimation value of the transformer. By adopting the real-time monitoring method for the direct-current resistance of the transformer, the direct-current resistance of the transformer can be monitored on line in real time in the running state of the transformer.

Description

Technical Field

[0001] This invention relates to the field of transformers, specifically to a method and system for real-time monitoring of the DC resistance of a transformer. Background Technology

[0002] Transformers are crucial power transmission devices in power systems. The DC resistance of a transformer directly affects its power consumption, efficiency, and safe and reliable operation. Measuring the DC resistance of a transformer is an important task in power systems.

[0003] Currently, the measurement of DC resistance of transformers is conducted when the transformer is not in operation, i.e., in a static state, typically using the voltage drop method and the balanced bridge method. The voltage drop method involves applying a DC current across the resistor being measured, measuring the voltage, and then calculating the DC resistance value using Ohm's law. The balanced bridge method utilizes the balance principle of a bridge to measure DC resistance, allowing for direct reading of the measured value.

[0004] Both the voltage drop method and the bridge method are offline measurements, while transformers are normally in operation. Therefore, how to monitor the DC resistance of a transformer online in real time while it is in operation is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for real-time monitoring of the DC resistance of a transformer in operation.

[0006] In this embodiment of the invention, a method for real-time monitoring of the DC resistance of a transformer is provided, comprising:

[0007] The voltage and current signals on both sides of the primary and secondary sides of the transformer are collected in real time, and the effective value of the current, the active power value and the power difference between the two sides are calculated for each cycle on both sides of the primary and secondary sides of the transformer.

[0008] Based on the power difference and effective current value between the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss, and historical operating conditions, the DC resistance of the transformer is estimated and calculated to obtain the estimated real-time DC resistance value of the transformer.

[0009] In this embodiment of the invention, the voltage and current signals on both sides of the primary and secondary sides of the transformer are collected, and the effective value of the current, the active power value, and the power difference between the two sides are calculated for each cycle on both sides of the primary and secondary sides of the transformer, including:

[0010] Suppose the current on the primary side is sampled in time series as follows:

[0011] i 11 i 12 i 13 ...i 1k..., the voltage sampling value is: u 11 ,u 12 ,u 13 ......u 1k ....,

[0012] The current sampling value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22 ,u 23 ......u 2k ....,

[0013] The calculated active power for each cycle of the primary side is:

[0014]

[0015] The calculated active power value for each cycle on the secondary side is:

[0016]

[0017] The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP (2-1)3 =|P 13 -P 23 |,......

[0018] In this embodiment of the invention, based on the power difference and effective current value between the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss, and historical operating conditions, the DC resistance of the transformer is estimated to obtain the estimated real-time DC resistance value of the transformer. The calculation formula is as follows:

[0019]

[0020] in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1 The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

[0021] In this embodiment of the invention, the real-time monitoring method for the DC resistance of a transformer further includes:

[0022] The transformer is monitored in real time based on the estimated real-time DC resistance value, and an alarm is triggered when the transformer malfunctions.

[0023] In this embodiment of the invention, the transformer is monitored in real time based on the estimated real-time DC resistance value, and an alarm is triggered when an abnormality occurs in the transformer, including:

[0024] The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met:

[0025] In the formula: R k This is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D The time limit threshold;

[0026] After the warning is issued, the transformer current, voltage, active power, reactive power, and power consumption parameters are stored and displayed in real time.

[0027] In this embodiment of the invention, a real-time monitoring system for the DC resistance of a transformer is also provided, comprising:

[0028] The transformer parameter acquisition and calculation module is used to acquire the voltage and current signals on both sides of the primary and secondary sides of the transformer in real time, and to calculate the effective value of the current, the active power value and the power difference between the two sides for each cycle on both sides of the primary and secondary sides of the transformer.

[0029] The transformer DC resistance estimation module is used to estimate the DC resistance of the transformer based on the power difference and effective current value between the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss and historical operating conditions, to obtain the real-time DC resistance estimate of the transformer.

[0030] In this embodiment of the invention, the transformer parameter acquisition and calculation module acquires the voltage and current signals on both sides of the primary and secondary sides of the transformer, and calculates the effective value of the current, the active power value, and the power difference between the two sides for each cycle on both sides of the primary and secondary sides, including:

[0031] Suppose the current on the primary side is sampled in time series as follows:

[0032] i 11, i 12, i 13 ...i 1k ..., the voltage sampling value is: u 11, u 12, u 13 ......u 1k ....,

[0033] The current sampling value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22 ,u 23 ......u 2k ....,

[0034] The calculated active power for each cycle of the primary side is:

[0035]

[0036] The calculated active power value for each cycle on the secondary side is:

[0037]

[0038] The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP (2-1)3 =|P 13 -P 23 |,......

[0039] In this embodiment of the invention, the transformer DC resistance estimation module estimates the DC resistance of the transformer based on the power difference and effective current value between the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss, and historical operating data, to obtain a real-time estimated value of the transformer's DC resistance. The calculation formula is as follows:

[0040]

[0041] in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1 The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

[0042] In this embodiment of the invention, the real-time monitoring system for the DC resistance of the transformer further includes:

[0043] The early warning module is used to monitor the transformer in real time based on the estimated real-time DC resistance value of the transformer, and to issue an alarm when the transformer is abnormal.

[0044] In this embodiment of the invention, the early warning module monitors the transformer in real time based on the estimated real-time DC resistance value and issues an alarm when an abnormality occurs in the transformer, including:

[0045] The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met:

[0046] In the formula: R kThis is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D The time limit threshold;

[0047] After the warning is issued, the transformer current, voltage, active power, reactive power, and power consumption parameters are stored and displayed in real time.

[0048] Compared with existing technologies, the real-time monitoring method and system for transformer DC resistance of this invention calculates the effective values ​​of current, effective values ​​of voltage, active power, and the power difference between the primary and secondary sides of the transformer for each cycle based on real-time measured waveforms of voltage and current on both sides. Using the power difference and effective current values ​​on both sides, combined with the transformer's no-load loss, the DC resistance of the transformer is estimated and calculated, forming a real-time DC resistance curve. When the real-time DC resistance value exceeds the transformer's rated DC resistance threshold, it indicates a hidden problem in the transformer, providing an early warning. This method can effectively improve the transformer's accident prediction and pre-maintenance capabilities, ensuring the safe, reliable, and economical operation of the transformer. Attached Figure Description

[0049] Figure 1 This is a flowchart of a method for real-time monitoring of the DC resistance of a transformer according to an embodiment of the present invention.

[0050] Figure 2 This is a schematic diagram of the structure of a real-time monitoring system for the DC resistance of a transformer according to an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0053] like Figure 1 As shown in the figure, this embodiment of the invention provides a method for real-time monitoring of the DC resistance of a transformer, which includes steps S1-S3. These will be described in detail below.

[0054] Step S1: Real-time acquisition of voltage and current signals on both sides of the primary and secondary sides of the transformer, and calculation of the effective value of current, active power and power difference between the two sides for each cycle on both sides of the primary and secondary sides of the transformer.

[0055] It should be noted that the real-time monitoring method for transformer DC resistance in this embodiment of the invention is mainly applied to scenarios involving monitoring the current and voltage at both ends of a transformer, including but not limited to a comprehensive transformer monitoring and performance analysis platform. Before use, the comprehensive monitoring and performance analysis platform first connects to the current and voltage signals on both sides of the transformer's primary and secondary sides via the current transformer and voltage transformer in the transformer measurement circuit, and then calculates the effective value of the current, the active power value, and the power difference between the two sides for each cycle on both sides of the transformer's primary and secondary sides.

[0056] Specifically, in this embodiment of the invention, voltage and current signals from both sides of the primary and secondary sides of the transformer are acquired, and the effective value of current, active power, and power difference between the two sides are calculated for each cycle on both sides of the primary and secondary sides of the transformer. The calculation method is as follows:

[0057] Suppose the current on the primary side is sampled in time series as follows:

[0058] i 11 i 12 i 13 ...i 1k ..., the voltage sampling value is: u 11 ,u 12 ,u 13 ......u 1k ....,

[0059] The current sampling value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22 ,u 23 ......u 2k ....,

[0060] The calculated active power for each cycle of the primary side is:

[0061]

[0062] The calculated active power value for each cycle on the secondary side is:

[0063]

[0064] The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP(2-1)3 =|P 13 -P 23 |,......;

[0065] Based on the above calculation method, the active power difference curve for each cycle of the transformer is calculated by sequentially sampling the data sequence and recorded and saved.

[0066] Step S2: Based on the power difference and effective current value on the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss and historical operating conditions, the DC resistance of the transformer is estimated to obtain the real-time DC resistance estimate of the transformer.

[0067] In this embodiment of the invention, based on the power difference and effective current value between the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss, and historical operating conditions, the DC resistance of the transformer is estimated to obtain the estimated real-time DC resistance value of the transformer. The calculation formula is as follows:

[0068]

[0069] in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1 The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

[0070] Step S3: Monitor the transformer in real time based on the estimated real-time DC resistance value and issue an alarm when the transformer malfunctions.

[0071] Specifically, in this embodiment of the invention, the transformer is monitored in real time based on the estimated real-time DC resistance value, and an alarm is triggered when an abnormality occurs in the transformer, including:

[0072] The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met:

[0073] In the formula: R k This is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D The time limit threshold;

[0074] After the warning is issued, the transformer current, voltage, active power, reactive power, and power consumption parameters are stored and displayed in real time, and the transformer parameter acquisition, calculation, and analysis continue.

[0075] like Figure 2 As shown, corresponding to the above-described real-time monitoring method for transformer DC resistance, this embodiment of the invention also provides a real-time monitoring system for transformer DC resistance, which includes a transformer parameter acquisition and calculation module 1, a transformer DC resistance estimation module 2, and an early warning module 3. These will be described in detail below.

[0076] The transformer parameter acquisition and calculation module 1 is used to acquire the voltage and current signals on both sides of the primary and secondary sides of the transformer in real time, and to calculate the effective value of the current, the active power value and the power difference between the two sides for each cycle on both sides of the primary and secondary sides of the transformer.

[0077] In this embodiment of the invention, the transformer parameter acquisition and calculation module 1 acquires the voltage and current signals on both sides of the primary and secondary sides of the transformer, and calculates the effective value of the current, the active power value, and the power difference between the two sides for each cycle on both sides of the primary and secondary sides of the transformer. The calculation method is as follows:

[0078] Suppose the current on the primary side is sampled in time series as follows:

[0079] i 11 i 12 i 13 ...i 1k ..., the voltage sampling value is: u 11 ,u 12 ,u 13 ......u 1k ....,

[0080] The current sampling value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22 ,u 23 ......u 2k ....,

[0081] The calculated active power for each cycle of the primary side is:

[0082]

[0083] The calculated active power value for each cycle on the secondary side is:

[0084]

[0085] The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP (2-1)3 =|P 13 -P 23 |,......

[0086] The transformer parameter acquisition and calculation module 1 sequentially samples the data sequence to calculate and form the active power difference curve for each cycle of the transformer, and records and saves it.

[0087] The transformer DC resistance estimation module 2 is used to estimate the DC resistance of the transformer based on the power difference and effective current value on the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss and historical operating conditions, to obtain the estimated real-time DC resistance value of the transformer.

[0088] In this embodiment of the invention, the transformer DC resistance estimation module 2 estimates the DC resistance of the transformer based on the power difference and effective current value between the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss, and historical operating conditions, to obtain the estimated real-time DC resistance value of the transformer. The calculation formula is as follows:

[0089]

[0090] in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

[0091] The early warning module 3 is used to monitor the transformer in real time based on the estimated real-time DC resistance value of the transformer, and to issue an alarm when the transformer is abnormal.

[0092] In this embodiment of the invention, the early warning module 3 monitors the transformer in real time based on the estimated real-time DC resistance value of the transformer, and issues an alarm when the transformer malfunctions, including:

[0093] The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met:

[0094] In the formula: R k This is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D This is the time limit threshold.

[0095] After the early warning module 3 completes the early warning, it stores and displays the transformer current, voltage, active power, reactive power, and power consumption parameters in real time.

[0096] In summary, the real-time monitoring method and system for transformer DC resistance of this invention calculates the effective values ​​of current, effective values ​​of voltage, active power, and the power difference between the primary and secondary sides of the transformer for each cycle based on the real-time measured waveforms of voltage and current on both sides. Using the power difference and effective current values ​​on both sides, combined with the transformer's no-load loss, the DC resistance of the transformer is estimated and calculated, forming a real-time DC resistance curve. When the real-time DC resistance value exceeds the transformer's rated DC resistance threshold, it indicates a hidden problem in the transformer, providing an early warning. This method can effectively improve the transformer's accident prediction and pre-maintenance capabilities, ensuring the safe, reliable, and economical operation of the transformer.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for real-time monitoring of the DC resistance of a transformer, characterized in that, include: The voltage and current signals on both sides of the primary and secondary sides of the transformer are collected in real time, and the effective value of the current, the active power value and the power difference between the two sides are calculated for each cycle on both sides of the primary and secondary sides of the transformer. Based on the power difference and effective current value between the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss, and historical operating conditions, the DC resistance of the transformer is estimated and calculated to obtain the estimated real-time DC resistance value of the transformer.

2. The real-time monitoring method for the DC resistance of a transformer as described in claim 1, characterized in that, Acquire voltage and current signals from both the primary and secondary sides of the transformer, and calculate the effective current value, active power value, and power difference between the two sides for each cycle, including: Let the current on the primary side be sampled in time series as follows: i 11 i 12 i 13 ...i 1k ..., the voltage sampling value is: u 11 ,u 12 ,u 13 ......u 1k ..., the sampled current value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22, u 23 ......u 2k ...., The calculated active power for each cycle of the primary side is: The calculated active power value for each cycle on the secondary side is: The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP (2-1)3 =|P 13 -P 23 |,......

3. The real-time monitoring method for the DC resistance of a transformer as described in claim 2, characterized in that, Based on the power difference and effective current value between the primary and secondary sides of the transformer, and combined with the transformer's no-load loss, stray loss, and historical operating data, the DC resistance of the transformer is estimated and calculated to obtain the estimated real-time DC resistance value. The calculation formula is as follows: in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1 The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

4. The real-time monitoring method for the DC resistance of a transformer as described in any one of claims 1-3, characterized in that, Also includes: The transformer is monitored in real time based on the estimated real-time DC resistance value, and an alarm is triggered when the transformer malfunctions.

5. The real-time monitoring method for the DC resistance of a transformer as described in claim 4, characterized in that, The transformer is monitored in real time based on the estimated real-time DC resistance value, and an alarm is triggered when the transformer malfunctions, including: The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met: In the formula: R k This is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D The time limit threshold; After the warning is issued, the transformer current, voltage, active power, reactive power, and power consumption parameters are stored and displayed in real time.

6. A real-time monitoring system for the DC resistance of a transformer, characterized in that, include: The transformer parameter acquisition and calculation module is used to acquire the voltage and current signals on both sides of the primary and secondary sides of the transformer in real time, and to calculate the effective value of the current, the active power value and the power difference between the two sides for each cycle on both sides of the primary and secondary sides of the transformer. The transformer DC resistance estimation module is used to estimate the DC resistance of the transformer based on the power difference and effective current value between the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss and historical operating conditions, to obtain the real-time DC resistance estimate of the transformer.

7. The real-time monitoring system for the DC resistance of a transformer as described in claim 6, characterized in that, The transformer parameter acquisition and calculation module acquires the voltage and current signals on both sides of the primary and secondary sides of the transformer, and calculates the effective value of the current, the active power value, and the power difference between the two sides for each cycle on both sides of the primary and secondary sides, including: Suppose the current on the primary side is sampled in time series as follows: i 11 ,i 12 ,i 13 ......i 1k .......,Electronic connection:u 11 ,u 12 ,u 13 ......u 1k ...., The current sampling value on the secondary side is: i 21 i 22 i 23 ...i 2k ..., the voltage sampling value is: u 21 ,u 22 ,u 23 ......u 2k ...then the calculated active power value for each cycle of the primary side is: The calculated active power value for each cycle on the secondary side is: The difference in active power between the primary and secondary sides of the transformer in each cycle is: ΔP (2-1)1 =|P 11 -P 21 |,ΔP (2-1)2 =|P 12 -P 22 |,ΔP (2-1)3 =|P 13 -P 23 |,......

8. The real-time monitoring system for the DC resistance of a transformer as described in claim 7, characterized in that, The transformer DC resistance estimation module estimates the transformer's DC resistance based on the power difference and effective current value between the primary and secondary sides of the transformer, combined with the transformer's no-load loss, stray loss, and historical operating data. The resulting real-time estimated DC resistance value is calculated using the following formula: in: The effective value curve of the transformer primary current corresponds to ΔP (2-1)1 The square of the current value in the same period, ΔP0 is the no-load loss of the transformer, k r This is a comprehensive correction factor based on transformer stray losses and historical operating conditions, and k r =0.75—0.99, R1 is the transformer corresponding Point and ΔP (2-1)1 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)2 The square of the current value in the same period, R2 is the transformer corresponding Point and ΔP (2-1)2 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer. The effective value curve of the transformer primary current corresponds to ΔP (2-1)3 The square of the current value in the same period, R3 is the transformer corresponding Point and ΔP (2-1)3 The DC resistance of the same period is equivalent to the estimated value of the primary side of the transformer.

9. The real-time monitoring system for the DC resistance of a transformer as described in claim 6, characterized in that, Also includes: The early warning module is used to monitor the transformer in real time based on the estimated real-time DC resistance value of the transformer, and to issue an alarm when the transformer is abnormal.

10. The real-time monitoring system for the DC resistance of a transformer as described in claim 2, characterized in that, The early warning module monitors the transformer in real time based on the estimated real-time DC resistance value and issues an alarm when the transformer malfunctions, including: The estimated value is compared with a pre-set DC resistance threshold for the transformer. If the estimated value exceeds the threshold and remains so for a certain period of time, it indicates an abnormality in the transformer, and an early warning is issued when the following formula is met: In the formula: R k This is the real-time online estimate of the transformer's DC resistance equivalent to the transformer's primary winding, where k = 1, 2, 3, ..., R. D k is the preset DC resistance threshold of the transformer. d Let T be the reliability coefficient, and R be the reliability factor. k The duration of continuous operation after exceeding the value, T D The time limit threshold; After the warning is issued, the transformer current, voltage, active power, reactive power, and power consumption parameters are stored and displayed in real time.

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