Energy-saving control system and method of electric heat tracing system

Abstract

The invention provides an energy-saving control system and method for an electric heat tracing system, and relates to the technical field of offshore oil gas energy-saving control, and the system comprises a temperature control requirement setter, a tail end temperature acquisition system, a loop start-stop controller, a heat tracing power supply controller and a loop on-off relay. The method comprises the following steps of: obtaining required values of tail end temperatures of all loops and the tail end temperatures; subtracting the terminal temperature from a required value to obtain a temperature control error; the temperature control error is used as the input of a corresponding loop start-stop controller, and the on-off control quantity of each loop on-off relay is calculated; the on-off control quantity is used as the input of a loop on-off relay to realize the on-off of the power supply of the loop; the on-off control quantity, the tail end temperature and the environment temperature serve as input of a heat tracing power source controller, and output of the heat tracing power source controller is obtained through calculation and used for controlling a heat tracing power source. The device is used for ensuring the temperature required by the offshore oil and gas industrial production and saving electric energy at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving control for offshore oil and gas, and particularly to an energy-saving control system and method for an electric tracing system. Background Art

[0002] Offshore oil platforms are located offshore. Especially in the cold season, the temperature of platforms in the northern waters of our country will drop below freezing point. And the platforms themselves have functions such as oil and gas exploration, simple treatment, storage, compression and external transportation. In addition, the storage and transportation of domestic and fire-fighting water need to meet the temperature standards. Electric tracing has been widely used in offshore oilfields due to its safety and convenience.

[0003] Electric tracing provides a good guarantee for various pipelines, equipment, instruments, domestic water pipes, fire-fighting water pipes, etc. of offshore oil platforms operating at low temperatures.

[0004] However, the electric tracing system is a major energy consumer in oilfields and needs to be technically transformed for energy conservation and carbon reduction. It is of great significance to carry out energy-saving control on it.

[0005] Therefore, there is an urgent need for an energy-saving control system and method for an electric tracing system to solve the above technical problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an energy-saving control system and method for an electric tracing system to solve the technical problem of high energy consumption of the electric tracing system in the prior art. The preferred technical solutions provided by the present invention can produce many technical effects as described below.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] An energy-saving control system for an electric tracing system provided by the present invention includes a temperature control requirement setter, a terminal temperature acquisition system, a loop start-stop controller, a tracing power supply controller, and a loop on-off relay, wherein:

[0009] The terminal temperature acquisition system and the temperature control requirement setter are output in parallel and the difference is taken as the input of the loop start-stop controller;

[0010] The output of the loop start-stop controller is used as the input of the loop on-off relay and the tracing power supply controller.

[0011] Preferably, the loop start-stop controller includes a plurality of bangbang controllers.

[0012] An energy-saving control method for an electric tracing system provided by the present invention uses the above energy-saving control system for an electric tracing system, and includes the following steps:

[0013] Obtain the required value and the terminal temperature of each loop;

[0014] Take the difference between the terminal temperature and the required value to obtain the temperature control error;

[0015] Use the temperature control error as the input of the corresponding loop start-stop controller, and calculate the on-off control quantity of each loop on-off relay;

[0016] Use the on-off control quantity as the input of the loop on-off relay to realize the power on-off of the loop;

[0017] Use the on-off control quantity, the terminal temperature and the ambient temperature as the input of the tracing power supply controller, and calculate the output of the tracing power supply controller to control the tracing power supply.

[0018] Preferably, obtaining the required value of the terminal temperature of each loop includes:

[0019] The temperature requirement setter determines the required value T of the terminal temperature of each loop according to the oil and gas heat preservation process requirements ri (i = 1, 2, … n), where n is the number of loops.

[0020] Preferably, the temperature requirement setter solves the required value of the terminal temperature of each loop according to different pipeline lengths and process requirements, and the calculation method includes:

[0021]

[0022] Wherein, is the temperature demand coefficient per unit length of loop i; l i is the length of the tracing cable of loop i.

[0023] Preferably, using the temperature control error as the input of the corresponding loop start-stop controller, and calculating the on-off control quantity of each loop on-off relay, specifically includes:

[0024] Take the difference between each terminal temperature T i (i = 1, 2 …, n) and its set value T ri (i = 1, 2, … n) to obtain each temperature control error e T-r-1 (i = 1, 2, … n); use e T-r-1 as the input of the corresponding loop start-stop controller, and calculate the on-off control quantity Cv of each loop relay i (i = 1, 2, … n), and the calculation method includes:

[0025]

[0026] Wherein, er-T-i-max is the upper limit of allowable temperature deviation.

[0027] Preferably, the tracing power controller includes a control decision maker, and the output expression of the control decision maker includes:

[0028]

[0029] where l i , L io , r io are respectively the length, inductance per unit length, and resistance per unit length of the tracing cable for loop i; is the real-time calculated value of the current demand for loop i.

[0030] Preferably, the real-time calculated value of the current demand for loop i is calculated by the following method:

[0031]

[0032] where is the current demand coefficient determined by the temperature control error of loop i; I i (u, LR i (l i , L io , r io ) is the basic current calculated value required for the temperature control of loop i; u is the measured value of the output voltage of the electric tracing power supply system; LR i (l i , L io , r io ) are impedance parameters;

[0033] When selecting the on-off relay for the loop, it should satisfy:

[0034] Preferably, the calculation formula of the impedance parameter includes:

[0035] LR i (l i , L io , r io ) = (r io + jωL io )l i

[0036] where: ω is the alternating current frequency output by the electric tracing power supply system.

[0037] Preferably, the expression of the basic current calculated value required for the temperature control of loop i represented by the transfer function includes:

[0038]

[0039] Where: s is the Laplace operator;

[0040] I i (s) is the transfer function of the basic current required for the temperature control of loop i;

[0041] u(s) is the transfer function of the output voltage of the electric tracing power supply system;

[0042] LR i (s) is the transfer function of the impedance parameter;

[0043] Performing the inverse Laplace transform on I i (s) gives I i (u, LR i (l i , L io , r io ))

[0044] An energy-saving control system for an electric tracing system provided by the present invention includes a temperature control requirement setter, an end temperature acquisition system, a loop start-stop controller, a tracing power supply controller, and a loop on-off relay. Among them, the end temperature acquisition system and the temperature control requirement setter are output in parallel and the difference is used as the input of the loop start-stop controller; the output of the loop start-stop controller is used as the input of the loop on-off relay and the tracing power supply controller, which can ensure the temperature required for offshore oil and gas industrial production while saving electric energy.

[0045] An energy-saving control method for an electric tracing system provided by the present invention includes obtaining the required value and the end temperature of the end temperature of each loop, and taking the difference between the end temperature and the required value to obtain a temperature control error; using the temperature control error as the input of the corresponding loop start-stop controller, calculating the on-off control quantity of each loop on-off relay; using the on-off control quantity as the input of the loop on-off relay to realize the on-off of the power supply of the loop; using the on-off control quantity, the end temperature, and the ambient temperature as the input of the control decision maker of the tracing power supply, and calculating the output of the control decision maker to control the tracing power supply. This method is simple and clear, can effectively reduce the start-stop times, reduce the amplitude of the start-stop impact current of the tracing system power supply, and ensure the temperature required for offshore oil and gas industrial production while saving electric energy. Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0047] Figure 1It is a schematic structural diagram of the energy-saving control system of the electric tracing system of the present invention;

[0048] Figure 2 It is a flowchart of the energy-saving control method of the electric tracing system of the present invention. Specific embodiments

[0049] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope protected by the present invention.

[0050] Figure 1 It is a schematic structural diagram of this embodiment. As Figure 1 shown, the present invention provides an energy-saving control system for an electric tracing system, including a temperature control requirement setter, an end temperature acquisition system, a loop start-stop controller, a tracing power supply controller, and a loop on-off relay.

[0051] Among them, the end temperature acquisition system and the temperature control requirement setter are output in parallel and the difference is used as the input of the loop start-stop controller; the output of the loop start-stop controller is used as the input of the loop on-off relay and the tracing power supply controller.

[0052] Among them, the temperature control requirement setter in this embodiment is a calculator for solving the required end temperature values of each loop according to different pipeline lengths and process requirements. The end temperature acquisition system mainly consists of three parts, specifically including: a temperature sensor at the end, a temperature transmitter, and corresponding signal lines. The loop start-stop controller in this embodiment is implemented by single-chip microcomputer programming. The tracing power supply controller consists of a control decision maker and an electric tracing power supply system.

[0053] Specifically, the loop start-stop controller includes multiple bangbang controllers. Based on the BangBang energy-saving control system, it ensures the requirements of oil and gas industrial production while achieving power saving.

[0054] Figure 2 It is a flowchart of the energy-saving control method of the electric tracing system. As Figure 2 shown, the energy-saving control method of the electric tracing system adopts the above-mentioned energy-saving control system of the electric tracing system, and includes the following steps:

[0055] S101: Obtain the required value and the end temperature of the end temperature of each loop;

[0056] Specifically, in this embodiment, the temperature requirement setter determines the required value T of the end temperature of each loop according to the oil and gas heat preservation process requirements ri(i = 1, 2, …, n), where n is the number of circuits.

[0057] Among them, the temperature requirement setter solves the required values of the end temperatures of each circuit according to different pipeline lengths and process requirements. The calculation methods include:

[0058]

[0059] Among them, is the temperature demand coefficient per unit length of circuit i; l i is the length of the tracing cable for circuit i.

[0060] S102: Subtract the end temperature from the required value to obtain the temperature control error;

[0061] Specifically, in this embodiment, the end temperatures T i (i = 1, 2, …, n) of each circuit collected at the end are subtracted from the corresponding T ri (i = 1, 2, …, n) calculated by the temperature requirement setter to obtain the temperature control error e T-r-1 (i = 1, 2, …, n) of each circuit.

[0062] S103: Take the temperature control error as the input of the corresponding circuit start-stop controller, and calculate the on-off control quantity of the on-off relay for each circuit;

[0063] Specifically, in this embodiment, the end temperatures T i (i = 1, 2, …, n) are subtracted from their set values T ri (i = 1, 2, …, n) to obtain the temperature control errors e T-r-1 (i = 1, 2, …, n); e T-r-1 is taken as the input of the corresponding circuit BangBang controller, and the on-off control quantity Cv i (i = 1, 2, …, n) of the relay for each circuit is calculated. The calculation methods include:

[0064]

[0065] Among them, e r-T-i-max is the upper limit of the allowable temperature deviation.

[0066] S104: Take the on-off control quantity as the input of the circuit on-off relay to realize the power on and off of the circuit;

[0067] That is, the output Cv i of the corresponding BangBang controller is taken as the input of the control quantity of the circuit breaker for the corresponding circuit, so as to realize the power on and off of the circuit.

[0068] S105: Use the on / off control quantity, the end temperature, and the ambient temperature as the inputs of the tracing power supply controller, and calculate the output of the tracing power supply controller to control the tracing power supply.

[0069] Specifically, the outputs Cv of all BangBang controllers i (i = 1, 2, … n), the end temperatures T of each loop collected by the end temperature i (i = 1, 2, …, n) and the ambient temperature are used as the inputs of the control decision maker of the electric tracing power supply, and the output Cv of the control decision maker of the electric tracing power supply is calculated to control the power supply of the electric tracing system.

[0070] Each loop's BangBang controller here is implemented through a hysteresis loop as follows:

[0071]

[0072] where e r-T-i-max is the upper limit of the allowable temperature deviation.

[0073] The control decision maker of the tracing power supply here is selected as a multi-dimensional weighted decision-making mode, and the expression of this control is as follows:

[0074]

[0075] where, l i , L io , r io are respectively the length of the tracing cable, the inductance per unit length, and the resistance per unit length of loop i; is the real-time calculated value of the tracing current demand of loop i.

[0076] Specifically, the real-time calculated value of the tracing current demand of loop i in this embodiment is calculated as follows:

[0077]

[0078] where, is the current demand coefficient determined by the temperature control error of loop i; I i (u, LR i (l i , L io , r io ) is the basic current calculated value required for the temperature control of loop i; u is the measured value of the output voltage of the electric tracing power supply system; LR i (l i , L io , r io ) are impedance parameters.

[0079] The loop on / off relay should meet the following requirements when selected:

[0080] In this embodiment, specifically, the calculation formula of the impedance parameter includes: LR i (l i , L io , r io ) = (r io + jωL io )l i

[0081] Where: ω is the alternating current frequency output by the electric tracing power supply system.

[0082] The calculated value I of the basic current required for the temperature control of loop i i (u, LR i (l i , L io , r io ) represented by the transfer function includes:

[0083]

[0084] Where: s is the Laplace operator;

[0085] I i (s) is the transfer function of the basic current required for the temperature control of loop i;

[0086] u(s) is the transfer function of the output voltage of the electric tracing power supply system;

[0087] LR i (s) is the transfer function of the impedance parameter;

[0088] Performing the inverse Laplace transform on I i (s) gives I i (u, LR i (l i , L io , r io ).

[0089] This method is simple and clear, can effectively reduce the number of starts and stops, reduce the amplitude of the starting and stopping impact current of the tracing system power supply, and save electric energy while ensuring the temperature required for offshore oil and gas industrial production.

[0090] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An energy-saving control system for an electric tracing system, characterized in that, It includes a temperature control requirement setter, an end temperature acquisition system, a loop start-stop controller, a tracing power supply controller, and a loop on-off relay, where: The end temperature acquisition system and the temperature control requirement setter are output in parallel and the difference is taken as the input of the loop start-stop controller; The output of the loop start-stop controller is used as the input of the loop on-off relay and the tracing power supply controller.

2. The energy-saving control system of an electric tracing system according to claim 1, characterized in that: The loop start-stop controller includes a plurality of bangbang controllers.

3. An energy-saving control method for an electric tracing system, characterized in that, An energy-saving control system for the electric tracing system according to claim 1 or 2 includes the following steps: Obtain the required value and the end temperature of the end temperature of each loop; Take the difference between the end temperature and the required value to obtain a temperature control error; Use the temperature control error as the input of the corresponding loop start-stop controller, and calculate the on-off control quantity of each loop on-off relay; Use the on-off control quantity as the input of the loop on-off relay to realize the power on-off of the loop; Use the on-off control quantity, the end temperature, and the ambient temperature as the input of the tracing power supply controller, and calculate the output of the tracing power supply controller to control the tracing power supply.

4. The energy-saving control method of the electric tracing system according to claim 3, characterized in that: The obtaining of the required value of the end temperature of each loop includes: The temperature requirement setter determines the required value T of the end temperature of each circuit according to the requirements of the oil and gas heat preservation process ri (i = 1, 2, … n), where n is the number of circuits.

5. The energy-saving control method of the electric tracing heating system according to claim 4, characterized in that: The temperature requirement setter solves the required value of the end temperature of each loop according to different pipeline lengths and process requirements. The calculation method includes: Among them, is the temperature demand coefficient per unit length of loop i; l i is the length of the tracing cable for loop i.

6. The energy-saving control method of the electric tracing system according to claim 3, wherein: Use the temperature control error as the input of the corresponding loop start-stop controller, and calculate the on-off control quantity of each loop on-off relay. Specifically, it includes: Subtract the respective end temperatures T i (i = 1, 2…, n) from their set values T ri (i = 1, 2,…n) to obtain the respective temperature control errors e T-r-1 (i = 1, 2,…n); Take e T-r-1 as the input of the start / stop controller for the corresponding circuit, and calculate the on / off control quantity Cv of each circuit relay i (i = 1, 2, … n), and the calculation method includes: where, e r-T-i-max is the upper limit of the allowable temperature deviation.

7. The energy-saving control method of the electric tracing system according to claim 6, characterized in that: The tracing power supply controller includes a control decision maker, and the output expression of the control decision maker includes: Among them, l i , L io , r io are respectively the length of the tracing cable of loop i, the inductance per unit length, and the resistance per unit length; is the real-time calculated value of the current demand of loop i.

8. The energy-saving control method of the electric tracing system according to claim 7, characterized in that: The real-time calculated value of the current demand of circuit i The calculation method includes: Among them, is the current demand coefficient determined by the temperature control error of loop i; I i (u, LR i (l i , L io , r io ) is the calculated value of the basic current required for the temperature control of loop i; u is the measured value of the output voltage of the electric tracing power supply system; LR i (l i , L io , r io ) are impedance parameters; The circuit on-off relay should meet the following requirements when selected:

9. The energy-saving control method of the electric tracing system according to claim 8, characterized in that: The calculation formula of the impedance parameter includes: LR i (l i ,L io ,r io )=(r io +jωL io )l i Where: ω is the alternating current frequency output by the electric tracing power supply system.

10. The energy-saving control method of the electric tracing system according to claim 9, characterized in that, The expression of the calculated value of the basic current required for the temperature control of loop i represented by a transfer function includes: Where: s is the Laplace operator; I i (s) is the transfer function of the basic current required for the temperature control of loop i; u(s) is the transfer function of the output voltage of the electric tracing power supply system; LR i (s) is the transfer function of the impedance parameter; Performing the inverse Laplace transform on I i (s) gives I i (u, LR i (l i , L io , r io ).

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