System and method for monitoring and controlling MVDC cooling system

Abstract

A system for monitoring and controlling an MVDC cooling system is disclosed. A system for monitoring and controlling an MVDC cooling system, according to the present invention, comprises: a control unit that controls the cooling system; a temperature sensor that generates temperature information of cooling water flowing in a valve unit; a flow rate sensor that generates flow rate information of the cooling water flowing in the valve unit; pressure sensors that generate pressure information of the valve unit, a main pump, and an expansion tank; and a water level sensor that generates water level information of the expansion tank.

Description

Monitoring and control system and method for MVDC cooling system

[0001] The present invention relates to a monitoring and control system and method for an MVDC cooling system.

[0002] MVDC (Midium Voltage Direct Current) technology is a DC transmission and substation technology with a voltage level of 1.5kV to 100kV and a large power transmission capacity for intermediate connection between HVDC technology applied to transmission systems and LVDC technology of low-voltage users in the configuration of DC power grids.

[0003] With the increase in DC-based renewable energy sources and the advancement of power conversion technology, the construction of MVDC converters has been promoted for energy efficiency, and accordingly, diagnostic and monitoring technologies have been required for their stable operation.

[0004] DC-based voltage and current sensors for MVDC applications have different structures and operating principles from AC types, requiring new technological development. In particular, as domestic development of the typical MVDC voltage level of 42 kV has not been pursued, commercialization technology development and securing of original technology are necessary.

[0005] In addition, passive partial discharge, leakage current, and vibration sensors for diagnosing core AC substation devices (circuit breakers, transformers, switches, arresters, etc.) and motors have been commercialized and are being applied in the field, but there is no development of diagnostic sensors for core electrical devices for MVDC protection (DC circuit breakers, DC switches, power converters, etc.) and core cooling device devices (motors, pumps, etc.).

[0006] In particular, the cooling system of the MVDC converter is an essential element for the stable operation of the system, so a system and method for monitoring and controlling it are essential.

[0007] The technical problem to be solved by the present invention is to provide a monitoring and control system and method for an MVDC cooling system that efficiently monitors each component of the MVDC cooling system and performs necessary control.

[0008] In order to solve the above technical problem, a monitoring and control system of an MVDC cooling system according to an embodiment of the present invention comprises: a valve unit respectively disposed at the inlet and outlet of the MVDC converter; a main pump disposed on a cooling water circulation path; and an expansion tank installed on a branched path so as to join the circulation path; and a cooling unit; and a control unit for controlling the cooling system; a temperature sensor for generating temperature information of cooling water flowing in the valve unit; a flow rate sensor for generating flow rate information of cooling water flowing in the valve unit; a pressure sensor for generating pressure information of the valve unit, the main pump, and the expansion tank; and a water level sensor for generating water level information of the expansion tank; wherein the control unit can analyze information generated by the temperature sensor, the flow rate sensor, the pressure sensor, and the water level sensor to generate control information regarding the cooling system or a related system.

[0009] In one embodiment of the present invention, the control unit compares temperature, flow rate, and pressure information measured in the valve unit with preset temperature, flow rate, and pressure values, respectively, and generates control information when the sensed temperature, flow rate, and pressure values ​​are out of the operating condition range of the cooling system, wherein the control information is stop request information for an MVDC converter module that is out of the operating condition range, or the control unit compares water level and pressure information measured in the expansion tank with preset water level and pressure values, respectively, and generates control information when the sensed water level and pressure information values ​​are greater than the preset values, wherein the control information is request information for opening a pressure reducing valve included in the expansion tank and reducing or stopping an MVDC load, or the control unit calculates differential pressure information using pressure information at the inlet and outlet of the main pump, compares it with preset differential pressure values, and generates control information when the sensed temperature, flow rate, and pressure values ​​are out of the operating condition range of the cooling system, wherein the control information may be main pump stop request information and make-up water pump operation request information.

[0010] In order to solve the above technical problem, a monitoring and control method of an MVDC cooling system according to an embodiment of the present invention comprises: a cooling system including a valve unit respectively disposed at the inlet and outlet of the MVDC converter; a main pump disposed on a cooling water circulation path; an expansion tank installed on a branched path so as to join the circulation path; and a cooling unit; and a step of monitoring and controlling a failure; and a step of monitoring and controlling an operating condition; wherein the step of monitoring and controlling a failure comprises: a step of generating temperature, flow rate, pressure, and water level information; a step of analyzing the information to generate control information; And a step of transmitting the control information to each component or related system; wherein the control information is generated when the temperature, flow rate, and pressure information measured in the valve unit are compared with preset temperature, flow rate, and pressure values, respectively, and the sensed temperature, flow rate, and pressure values ​​are out of the operating condition range of the cooling system, and at this time, the control information is stop request information for the MVDC converter module that is out of the operating condition range, or the control information is generated when the water level and pressure information measured in the expansion tank are compared with preset water level and pressure values, respectively, and the sensed water level and pressure information values ​​are greater than the preset values, and at this time, the control information is request information for opening a pressure reducing valve included in the expansion tank and reducing or stopping an MVDC load, or the control information is generated when the differential pressure information is calculated using the pressure information of the inlet and outlet of the main pump and the differential pressure information is compared with the preset differential pressure value, and the control information is generated when the operating condition range of the cooling system is out of the operating condition range, and at this time, the control information may be main pump stop request information and make-up water pump operation request information.

[0011] In one embodiment of the present invention, the step of monitoring and controlling the operating condition may include: a step of generating temperature information of a valve unit outlet; a step of comparing the temperature information with a preset value to determine a temperature change; a step of reducing or increasing the main pump output and the fan output included in the cooling unit, respectively, according to a control variable value according to a first criterion when the temperature decreases or increases; a step of regenerating the temperature information of the valve unit outlet; and a step of comparing the regenerated temperature information with a preset temperature value to determine a difference, and generating a second criterion different from the first criterion so that the control variable value is adjusted when the difference is greater than the preset value.

[0012] The present invention has the effect of efficiently monitoring each component of an MVDC cooling system and performing necessary control to stably operate the MVDC system.

[0013] FIG. 1 schematically illustrates a monitoring and control system for an MVDC cooling system according to one embodiment of the present invention.

[0014] FIG. 2 specifically illustrates a part of the configuration of a monitoring and control system for an MVDC cooling system according to one embodiment of the present invention.

[0015] FIG. 3 schematically illustrates a monitoring and control method for an MVDC cooling system according to one embodiment of the present invention.

[0016] FIG. 4 is a different embodiment of a part of a monitoring and control method for an MVDC cooling system according to one embodiment of the present invention.

[0017] FIG. 5 is an example of a monitoring and control method for an MVDC cooling system according to one embodiment of the present invention.

[0018]

[0019] The Korean national research and development projects that supported this invention are as follows.

[0020] [Project ID]1415186646

[0021] [Assignment Number]20225500000120

[0022] [Ministry Name] Ministry of Trade, Industry and Energy

[0023] [Name of project management (specialized) organization] Korea Institute of Energy Technology Evaluation and Planning

[0024] [Research Project Name] Next-Generation AC / DC Hybrid Power Distribution Network Technology Development Project

[0025] [Research Project Name] Development of Measurement, Diagnosis, and Reliability Evaluation Technology for Extra-High Voltage Direct Current Distribution

[0026] [Contribution rate] 1 / 1

[0027] [Name of the project performing organization] Amitech Co., Ltd.

[0028] Research Period: September 1, 2022 - August 31, 2027

[0029] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0030] In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description is omitted.

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0032]

[0033] Figure 1 schematically illustrates a monitoring and control system (10) of an MVDC cooling system according to one embodiment of the present invention.

[0034] Referring to FIG. 1, a monitoring and control system (10) of an MVDC cooling system according to one embodiment of the present invention includes a control unit (100) and a cooling system (200).

[0035] The control unit (100) is connected to the cooling system (200).

[0036] The control unit (100) can control and monitor the cooling system (200), supply power to the cooling system, and transmit and receive information with the upper system of the MVDC system.

[0037] Specifically, the control unit (100) can supply and cut off power, control, and transmit signals to cooling system components.

[0038] For example, the control unit (100) can control the cooling water temperature by controlling the fan for the cooling unit (390) of the cooling system (200) and control the operation of the pump.

[0039] For example, the control unit (100) may receive information on the temperature and flow rate of the coolant at the inlet and outlet of the converter, receive information on the level and pressure of the expansion tank (360), receive information on the converter inlet pressure, receive information on the pump inlet and outlet pressure, and receive information on the operating status of the fan of the pump and cooling unit (390) to process the related information.

[0040] The cooling system (200) is connected to the control unit (100) and transmits and receives information.

[0041] The cooling system (200) performs cooling treatment so that it can operate within the desired temperature range, taking into account the heat generation of the MVDC converter station.

[0042] FIG. 2 specifically illustrates a part of the configuration of a monitoring and control system of an MVDC cooling system according to one embodiment of the present invention.

[0043] Referring to FIG. 2, the monitoring and control system of the MVDC cooling system according to one embodiment of the present invention may further include a valve unit (310), a conveying unit (320), a main pump (330), a degassing tank (340), an ion removal tank (350), an expansion tank (360), a supplementary water tank (370), a supplementary water pump (380), a cooling unit (390), a temperature sensor (410), a flow sensor (420), a pressure sensor (430), and a water level sensor (440). Here, the valve unit (310), the conveying unit (320), the main pump (330), the degassing tank (340), the ion removal tank (350), the expansion tank (360), the supplementary water tank (370), the supplementary water pump (380), and the cooling unit (390) may be included in the cooling system (200).

[0044] The valve unit (310) can be installed at the inlet and outlet of the MVDC converter.

[0045] The valve unit (310) can be connected to the transfer unit (320). The transfer unit (320) is composed of a piping system and forms a passage for transferring heat and material.

[0046] The main pump (330) is placed on the path from the valve section (310) to the cooling section (390).

[0047] The main pump (330) provides power to water or glycol flowing along the circulation path within the cooling system to circulate it.

[0048] The main pump (330) may further include a check valve to prevent water hammering caused by a sudden decrease in flow rate when stopped, and a butterfly valve installed at the inlet and outlet of the pump to minimize cooling water consumption during maintenance.

[0049] The main pump (330) may include an electric motor with a soft starter function.

[0050] The degassing tank (340) is placed on the path from the valve unit (310) to the main pump (330).

[0051] The degassing tank (340) can discharge bubbles generated by a decrease in gas saturation due to pressure and temperature differences generated in the valve section (310) of the MVDC converter to the outside. In addition, oxygen and hydrogen gases generated by the influence of electricity applied to the valve section (310) can also be removed.

[0052] The ion removal tank (350) is placed on a branched path.

[0053] The ion removal tank (350) may include an ion exchange resin. The ion exchange resin can remove ions contained in the cooling water. Anions and cations present in the cooling water can be bound to the ion exchange resin and captured.

[0054] The expansion tank (360) is placed on a branched path.

[0055] The expansion tank (360) can compensate for thermal expansion or contraction according to the temperature of the coolant. The expansion tank (360) can include a pressure relief valve.

[0056] The expansion tank (360) maintains a constant pressure in the cooling system and can detect leaks within the cooling system.

[0057] The expansion tank (360) may further include a safety valve to prevent momentary pressure increases from being discharged outside the cooling system.

[0058] The supplementary water tank (370) is placed on the branched path.

[0059]

[0060] *The supplementary water tank (370) can store supplementary water. The supplementary water contains premixed pure water / propylene glycol.

[0061] The make-up water tank (370) is connected to a make-up water pump (380) to provide make-up water. The make-up water pump (380) supplies make-up water so that it can join the cooling water circulation path.

[0062] The cooling unit (390) is placed on the circulation path.

[0063] The cooling unit (390) can lower the temperature that has been raised by heat exchange and the amount of heat generated in the valve unit (310) of the MVDC converter to the desired normal range.

[0064] Temperature sensors (410) are respectively placed at the inlet and outlet of each valve section (310). The schematic locations of the temperature sensors (410) are indicated in the shape of ★ in Fig. 2.

[0065] The temperature sensor (410) can generate cooling water inlet and outlet temperature information for each channel and provide it to the control unit (100).

[0066] The control unit (100) can compare the cooling water inlet and outlet temperatures of each channel with preset values ​​and perform necessary control for each channel, inlet, and outlet.

[0067] The flow sensor (420) is placed at the inlet and outlet of each valve unit (310). The schematic location of the flow sensor (420) is indicated in the shape of ■ in Fig. 2.

[0068]

[0069] *The temperature sensor (410) can generate information on the cooling water flow rate for each channel and provide it to the control unit (100).

[0070] The control unit (100) can compare the cooling water flow rate of each channel with a preset value and perform necessary control for each channel.

[0071] Pressure sensors (430) can be installed at the inlet and outlet of each tank and pump. The schematic location of the pressure sensors (430) is indicated by a ● shape in Fig. 2.

[0072] The pressure sensor (430) can generate pressure information within each tank and the pressure at the pump inlet and outlet and provide the information to the control unit (100).

[0073] The control unit (100) can compare the pressure information with a preset value and perform necessary control on the tank or pump.

[0074] The water level sensor (440) can be installed in the expansion tank (360).

[0075] The water level sensor (440) can generate information about the water level of the fluid stored in the expansion tank (360) and provide it to the control unit (100).

[0076] The control unit (100) can compare information about the water level with a preset value and perform necessary control on the expansion tank (360).

[0077]

[0078] Hereinafter, a monitoring and control method for an MVDC cooling system according to an embodiment of the present invention will be described with the MVDC cooling system as the main body.

[0079] Each step of the present invention does not necessarily have to be performed sequentially, and the order of each step may be changed or multiple steps may be performed simultaneously.

[0080]

[0081] FIG. 3 schematically illustrates a monitoring and control method for an MVDC cooling system according to one embodiment of the present invention.

[0082] The S500 step is a step to monitor and control failures in the MVDC cooling system, and the S600 step is a step to monitor and control the cooling system operating conditions.

[0083] In step S510, at least one of the temperature sensor (410), the flow sensor (420), the pressure sensor (430), and the water level sensor (440) generates sensing information.

[0084] In step S520, the control unit (100) analyzes the sensing information to determine whether to generate control information.

[0085] In step S530, the control unit (100) transmits control information to each component.

[0086]

[0087] Figure 4 illustrates different embodiments of steps S510 to S530 in different components and situations.

[0088] Referring to FIG. 4a, in step S510, the temperature sensor (410), the flow sensor (420), and the pressure sensor (430) generate cooling water temperature, flow rate, and pressure information at the inlet and outlet of the MVDC converter, respectively. Although not shown in FIG. 2, the pressure sensor (430) is assumed to be installed.

[0089] The generated temperature, flow rate and pressure information can be provided to the control unit (100).

[0090] In step S520, the control unit (100) compares the provided temperature, flow rate, and pressure information with preset temperature, flow rate, and pressure values ​​to determine whether to generate control information.

[0091] The control unit (100) may generate control information when the sensed temperature, flow rate, and pressure values ​​are outside the operating condition range of the cooling system, and may not generate control information in other cases.

[0092] The control information may be information regarding a stop request for an MVDC converter module that is out of its operating condition range.

[0093] In step S530, the control unit (100) can transmit stop request information for the MVDC converter module to the MVDC converter module that is out of the operating condition range.

[0094] Referring to FIG. 4b, in step S510, the pressure sensor (430) and the water level sensor (440) generate water level and pressure information of the expansion tank (360).

[0095] The generated water level and pressure information can be provided to the control unit (100).

[0096] In step S520, the control unit (100) compares the provided water level and pressure information with preset water level and pressure information values ​​to determine whether to generate control information.

[0097] The control unit (100) may generate control information when the sensed water level and pressure information values ​​are greater than preset values, and may not generate control information in other cases.

[0098] The control information may be a request to open a pressure reducing valve and reduce or stop the MVDC load.

[0099] In step S530, the control unit (100) can transmit request information for opening the pressure reducing valve and reducing or stopping the MVDC load to the expansion tank (360) and related systems.

[0100] Referring to FIG. 4c, in step S510, the pressure sensor (430) generates pressure information at the inlet and outlet of the main pump (330). Although not shown in FIG. 2, it is assumed that the pressure sensor (430) is installed at the required location.

[0101] The generated pressure information can be provided to the control unit (100).

[0102] In step S520, the control unit (100) calculates differential pressure information between the inlet and outlet using the provided pressure information and compares it with a preset differential pressure value to determine whether to generate control information.

[0103] The control unit (100) may generate control information when the differential pressure value is outside the operating condition range of the cooling system, and may not generate control information in other cases.

[0104] The control information may be information regarding a request to stop the main pump (330) and start the supplementary water pump (380).

[0105] In step S530, the control unit (100) can transmit information requesting the M main pump (330) to stop and the supplementary water pump (380) to start the main pump (330) and the supplementary water pump (380).

[0106] FIG. 5 is an example of a monitoring and control method for an MVDC cooling system according to one embodiment of the present invention.

[0107] Referring to FIG. 5, in step S610, the temperature sensor (410) generates cooling water temperature information at the outlet of the MVDC converter and provides it to the control unit (100).

[0108] At step S620, the controller compares the received temperature information with a preset value to determine the temperature change. If the temperature is lower than the preset value, it is considered a decrease and proceeds to step S630. If the temperature is higher than the preset value, it is considered a increase and proceeds to step S640.

[0109] In step S630, the control unit (100) reduces the output of the main pump (330) and the fan output of the cooling unit (390) according to the control variable value according to the first criterion.

[0110] In step S640, the control unit (100) increases the output of the main pump (330) and the fan output of the cooling unit (390) according to the control variable value according to the first criterion.

[0111] At step S650, the temperature sensor (410) again generates cooling water temperature information at the outlet of the MVDC converter and provides it to the control unit (100).

[0112] In step S660, the control unit (100) determines whether the control result temperature is close to the preset value based on the control variable value according to the first criterion. If the difference is greater than the criterion value, the control unit (100) can generate and store a second criterion that adjusts the control variable values. For example, if the decrease after control is small compared to the increase in temperature, the increase in pump output and fan output can be increased. For example, if the increase after control is large compared to the decrease in temperature, the decrease in pump output and fan output can be reduced. In other words, if the pump output and fan output are excessively reduced, the decrease can be reduced in the future to control closer to the normal operating temperature.

[0113] Once the control variable values ​​have been adjusted, you can return to the beginning and repeat monitoring and control.

[0114]

[0115] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. In this application, terms such as "comprise" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Claims

1. In a system for monitoring and controlling an MVDC cooling system, The above cooling system, Valve units respectively positioned at the inlet and outlet of the above MVDC converter; A main pump arranged in the cooling water circulation path; and An expansion tank installed on a branched path to join the above-mentioned circulation path; and including a cooling unit; A control unit for controlling the above cooling system; A temperature sensor that generates temperature information of the coolant flowing in the above valve section; A flow sensor that generates information on the flow rate of coolant flowing in the above valve section; A pressure sensor that generates pressure information of the above valve unit, main pump and expansion tank; and A water level sensor that generates water level information of the above expansion tank; A monitoring and control system for an MVDC cooling system, characterized in that the control unit analyzes information generated by the temperature sensor, flow sensor, pressure sensor, and water level sensor to generate control information regarding the cooling system or related system.

2. In paragraph 1, The above control unit compares the temperature, flow rate and pressure information measured in the above valve unit with the preset temperature, flow rate and pressure values, respectively, and generates control information when the sensed temperature, flow rate and pressure values ​​are outside the operating condition range of the cooling system, wherein the control information is stop request information for the MVDC converter module that is outside the operating condition range. Or, the control unit compares the water level and pressure information measured in the expansion tank with preset water level and pressure values, respectively, and generates control information when the sensed water level and pressure information values ​​are greater than the preset values, wherein the control information is request information for opening a pressure reducing valve included in the expansion tank and reducing or stopping the MVDC load. Or, the control unit calculates differential pressure information using pressure information at the inlet and outlet of the main pump, compares it with a preset differential pressure value, and generates control information when the operating condition range of the cooling system is exceeded, wherein the control information is a monitoring and control system of an MVDC cooling system, characterized in that the control information is information requesting the main pump to stop and the make-up water pump to start.

3. A method for monitoring and controlling an MVDC cooling system, The above cooling system, Valve units respectively positioned at the inlet and outlet of the above MVDC converter; Main pump placed in the cooling water circulation path; An expansion tank installed on a branched path to join the above-mentioned circulation path; and including a cooling unit; Steps for monitoring and controlling faults; and A step for monitoring and controlling driving conditions; including: The steps for monitoring and controlling the above failure are: Steps to generate temperature, flow rate, pressure and level information; A step of analyzing the above information to generate control information; and A step of transmitting the above control information to each component or related system; The above control information is generated when the temperature, flow rate and pressure information measured in the valve section are compared with the preset temperature, flow rate and pressure values, respectively, and the sensed temperature, flow rate and pressure values ​​are outside the operating condition range of the cooling system. In this case, the control information is stop request information for the MVDC converter module that is outside the operating condition range. Or, the control information is generated when the sensed water level and pressure information measured in the expansion tank are compared with preset water level and pressure values, respectively, and the sensed water level and pressure information values ​​are greater than the preset values, and at this time, the control information is request information for opening the pressure reducing valve included in the expansion tank and reducing or stopping the MVDC load. Or, the control information is generated by calculating differential pressure information using pressure information at the inlet and outlet of the main pump and comparing it with a preset differential pressure value when the operating condition range of the cooling system is exceeded, and at this time, the control information is a monitoring and control method for an MVDC cooling system, characterized in that it is information requesting the main pump to stop and the make-up water pump to start.

4. In paragraph 3, The step of monitoring and controlling the above driving conditions is: Step of generating temperature information at the valve outlet; A step of comparing the above temperature information with a preset value to determine a temperature change; A step of reducing or increasing the main pump output and the fan output included in the cooling unit, respectively, according to the control variable value according to the first criterion when the above temperature decreases or increases; A step of regenerating temperature information at the valve outlet; and A method for monitoring and controlling an MVDC cooling system, characterized by comprising the steps of: comparing the re-generated temperature information with a preset temperature value to determine a difference, and generating a second reference different from the first reference so that the control variable value is adjusted if the difference is greater than the preset value.

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