Uninterruptible power supply switching control method for cable tunnel monitoring system

Abstract

The invention relates to an uninterruptible power supply switching control method for a cable tunnel monitoring system, and belongs to the technical field of disconnection of a power supply or distribution circuit system from a normal power supply and connection to a standby power supply. The method comprises the following steps: firstly, setting interval time for checking the cable tunnel monitoring system, and setting a voltage threshold and a voltage drop rate threshold; and when the cable tunnel monitoring system runs to each moment, collecting the temperature in the power box and the input voltage of the cable tunnel monitoring system, correcting the voltage according to a constructed correction formula, and judging whether the cable tunnel monitoring system needs to be switched to a standby power supply or not by combining the drop rate of the voltage. According to the method, whether switching operation needs to be carried out or not can be timely and accurately judged by carrying out temperature correction on the voltage and combining the voltage drop rate.

Description

TECHNICAL FIELD

[0001] The application relates to an uninterrupted power supply switching control method of a cable tunnel monitoring system, and belongs to the technical field of power supply or power distribution circuit systems being disconnected from normal power supply and connected to standby power supply (H02J9 / 04). BACKGROUND

[0002] As a key infrastructure for urban power transmission, a cable tunnel has a complex internal environment and numerous branches, so real-time monitoring of the operation in the cable tunnel is crucial. In order to prevent sudden failures from causing interruption of the main power supply, the current cable tunnel monitoring system generally configures a standby power supply in the power supply box to ensure that the monitoring system can still timely report fault information when the main power supply is disconnected, thereby gaining time for repair.

[0003] However, the current traditional switching control method is to directly read the line voltage and switch to the standby power supply when the voltage is too low, which often causes two problems in actual operation: one is that the switching is triggered due to voltage fluctuation, which interferes with the continuity of normal power supply, and the other is that the standby power supply is delayed after a fault occurs, causing information loss, which seriously affects the stable operation of the monitoring system. SUMMARY

[0004] The technical problem to be solved by the application is how to realize timely and accurate switching of the standby power supply in the cable tunnel monitoring system.

[0005] The technical solution provided by the application to solve the above technical problem is an uninterrupted power supply switching control method of a cable tunnel monitoring system, comprising the following steps:

[0006] Step 1: set an interval time t for checking the cable tunnel monitoring system, take the time for checking the cable tunnel monitoring system for the first time as the first time, take the time for checking the cable tunnel monitoring system for the second time after one interval time t as the second time, and take the time for checking the cable tunnel monitoring system for the nth time as the nth time;

[0007] Set a voltage threshold Q1 and a voltage drop rate threshold Q2;

[0008] Step 2: when the cable tunnel monitoring system runs to the nth time, collect the nth temperature Tn in the power supply box and the nth input voltage Vin input to the cable tunnel monitoring system by the main power supply in the power supply box , correct the nth input voltage Vin according to the following formula (1) to obtain the nth corrected voltage Vn

[0009] (1);

[0010] ​In the formula (1), A is a first correction function; B is a second correction function; C is a third correction function; V is a reference voltage, taking a value of 1.65V; T is a reference temperature, taking a value of 25℃; K1 is a first correction coefficient, 0.0001≤ K1≤ 0.0005; K2 is a second correction coefficient, 0.001≤ K2≤ 0.003; K3 is a third correction coefficient, 0.00001≤ K3≤ 0.00005; K4 is a fourth correction coefficient, 0.01≤ K4≤ 0.05; is the n-1 temperature in the power box at the n-1 moment;

[0011] The n voltage drop rate at the n moment is calculated according to the following formula (2)

[0012] (2);

[0013] In the formula (2), is the n-1 input voltage of the main power input to the cable tunnel monitoring system in the power box at the n-1 moment;

[0014] Step 3: when <Q1 and >Q2, the cable tunnel monitoring system is switched to the backup power supply.

[0015] Further, the step 1 collects the n input voltage is the binary digital amount E of the n input voltage of the main power input to the cable tunnel monitoring system in the power box read by the analog-digital converter first, and the n input voltage is calculated according to the following formula (3)

[0016] (3);

[0017] In the formula (3), m is the resolution of the analog-digital converter.

[0018] Further, after the step 3 switches the cable tunnel monitoring system to the backup power supply, the backup power supply is controlled to preferentially supply power to the communication module and the data acquisition module in the cable tunnel monitoring system.

[0019] The beneficial effects of this invention are as follows: Three correction functions are designed in the voltage correction formula. The first correction function characterizes the degree of nonlinear influence of temperature on voltage measurement results under different operating voltages. The second correction function corrects temperature drift, and the third correction function compensates for sensor response delay caused by rapid temperature changes. Coupling these three functions improves voltage accuracy and effectively prevents erroneous switching. Furthermore, the voltage drop rate is incorporated to distinguish normal voltage fluctuations, enabling timely and accurate switching of backup power in cable tunnel monitoring systems. Detailed Implementation

[0020] Example

[0021] This embodiment of a cable tunnel monitoring system uninterruptible power supply switching control method includes the following steps:

[0022] Step 1: Set the interval time for inspecting the cable tunnel monitoring system to t=1s. Take the time of the first inspection of the cable tunnel monitoring system as the first time, and take the time of the second inspection of the cable tunnel monitoring system after one interval time t as the second time, and so on up to the nth time.

[0023] Set the voltage threshold Q1 = 0.66V and the voltage drop rate threshold Q2 = 0.1V / s;

[0024] Step 2: When the cable tunnel monitoring system reaches time n, collect the temperature at time n inside the power supply box. The nth input voltage of the main power supply in the power supply box to the cable tunnel monitoring system. The nth input voltage is calculated according to formula (1). The nth corrected voltage is obtained by performing corrections.

[0025] (1);

[0026] In equation (1), A is the first correction function; B is the second correction function; C is the third correction function; V is the reference voltage, which is 1.65V; T is the reference temperature, which is 25℃; K1 is the first correction coefficient, 0.0001≤K1≤0.0005; K2 is the second correction coefficient, 0.001≤K2≤0.003; K3 is the third correction coefficient, 0.00001≤K3≤0.00005; K4 is the fourth correction coefficient, 0.01≤K4≤0.05; It is the (n-1)th temperature inside the power supply box at time (n-1);

[0027] In this embodiment, the nth input voltage of the cable tunnel monitoring system is first read from the main power supply in the power box via an analog-to-digital converter. The binary digital quantity E is then used to calculate the nth input voltage using the following formula.

[0028] ;

[0029] In the formula, m is the resolution of the analog-to-digital converter.

[0030] In cable tunnels, the effect of temperature on the measurement circuit is not constant but rather coupled with the measured voltage value itself. Therefore, this implementation constructs a voltage correction model to prevent temperature-induced deviations in voltage measurement results. Specifically, three correction functions are designed and coupled. The first correction function, serving as the coupling gain function, characterizes the degree of nonlinear influence of temperature on voltage measurement results under different operating voltages. The second correction function, serving as a higher-order temperature correction polynomial, corrects for temperature drift. Finally, a thermal hysteresis correction term related to the rate of temperature change, i.e., the third correction function, is introduced to compensate for sensor response delays caused by rapid temperature changes.

[0031] Furthermore, the first correction coefficient K1, serving as the coupling gain coefficient, determines the compensation strength for the voltage-temperature cross-nonlinear effect. A larger K1 value indicates a more sensitive model to the phenomenon of "different effects of temperature at different voltages," requiring greater compensation. The second correction coefficient K2, serving as the linear temperature drift coefficient, compensates for the linear shift of the measurement circuit with temperature changes. The third correction coefficient K3, serving as the nonlinear temperature drift coefficient, compensates for higher-order, nonlinear distortions caused by temperature. When the temperature range is large, linear compensation alone is no longer accurate, making this crucial. Finally, the fourth correction coefficient K4, serving as the thermal hysteresis coefficient, determines the compensation strength for dynamic errors caused by rapid temperature changes. A larger K4 value indicates a more "aggressive" compensation for the model's response delay to temperature changes. After multiple corrections using this voltage model, it was found that this voltage correction model can more accurately correct measurement errors at extreme temperatures such as -40℃ or +85℃ and under conditions of large voltage fluctuations.

[0032] In this embodiment, when the cable tunnel monitoring system operates to the 4th time point, the 4th temperature inside the power supply box is collected. =25℃ and the fourth input voltage of the main power input cable tunnel monitoring system in the power supply box. =2.0V; In equation (1), K1 is taken as 0.0003. K2 is 0.002 , K3 takes 0.00003 K4 is set to 0.03 , =25.2℃; the fourth corrected voltage is calculated according to formula (1). =1.994V

[0033] Calculate the rate of voltage drop at time n using equation (2).

[0034] (2);

[0035] In equation (2), It is the (n-1)th input voltage of the main power supply in the power supply box to the cable tunnel monitoring system at the (n-1)th time.

[0036] In this embodiment, the third input voltage of the main power input cable tunnel monitoring system in the power supply box at the third time point is... =2.05V, the fourth voltage drop rate is calculated according to equation (2). =0.056V / s.

[0037] Step 3: When <Q1 and >Q2, switch the cable tunnel monitoring system to backup power supply.

[0038] In this embodiment, at time 4, because =1.994V>=0.66V, =0.056V / s < 0.1 V / s, so there is no need to switch the cable tunnel monitoring system to the backup power supply.

[0039] Subsequently, at time 186, the cable tunnel monitoring system needs to be switched to backup power supply, and the backup power supply should be controlled to prioritize power supply to the communication module and data acquisition module in the cable tunnel monitoring system to ensure that the monitoring data is uninterrupted and that the last critical data upload can be completed.

[0040] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for switching control of uninterruptible power supply in a cable tunnel monitoring system, characterized in that... Includes the following steps: Step 1: Set the interval time t for inspecting the cable tunnel monitoring system. Take the time of the first inspection of the cable tunnel monitoring system as the first time, take the time of the second inspection of the cable tunnel monitoring system after one interval time t as the second time, and so on up to the nth time. Set the voltage threshold Q1 and the voltage drop rate threshold Q2; Step 2: When the cable tunnel monitoring system reaches time n, collect the temperature at time n inside the power supply box. The nth input voltage of the main power supply in the power supply box to the cable tunnel monitoring system. The nth input voltage is calculated using the following formula (1). The nth corrected voltage is obtained by performing corrections. (1)； In equation (1), A is the first correction function; B is the second correction function; C is the third correction function; V is the reference voltage, with a value of 1.65V; T is the reference temperature, taken as 25℃; K1 is the first correction factor, 0.0001≤K1≤0.0005; K2 is the second correction factor, 0.001≤K2≤0.003; K3 is the third correction factor, 0.00001≤K3≤0.00005; K4 is the fourth correction factor, 0.01≤K4≤0.

05. It is the (n-1)th temperature inside the power supply box at time (n-1); Calculate the rate of voltage drop at time n using equation (2). (2)； In equation (2), It is the (n-1)th input voltage of the main power supply in the power supply box to the cable tunnel monitoring system at the (n-1)th time. Step 3: When <Q1 and >Q2, switch the cable tunnel monitoring system to backup power supply.

2. The uninterruptible power supply switching control method for the cable tunnel monitoring system according to claim 1, characterized in that: Step 1 involves acquiring the nth input voltage. The nth input voltage of the cable tunnel monitoring system is first read from the main power supply in the power supply box via an analog-to-digital converter. The binary digital quantity E is then used to calculate the nth input voltage according to the following formula (3). （3）； In equation (3), m is the resolution of the analog-to-digital converter.

3. The uninterruptible power supply switching control method for the cable tunnel monitoring system according to claim 1, characterized in that: After switching the cable tunnel monitoring system to backup power in step 3, the backup power is controlled to prioritize powering the communication module and data acquisition module within the cable tunnel monitoring system.

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