JP6463908B2 - Transformer cooling system and transformer cooling method for underground substation - Google Patents

Description

  The present invention relates to a cooling facility for a substation facility, and more particularly to a transformer cooling system and a transformer cooling method for an underground substation.

  In general, substations installed in urban areas are often installed in the underground part of buildings and are called underground substations. This underground substation is an important facility for power transmission and distribution in urban areas, and the largest is a 500 kV class facility. Such underground substations tend to close up as a social problem such as causing disruption of the urban area due to the supply of electric power to the major institutions in the urban area. Therefore, improving the reliability of underground substations is a major proposition.

  Because of the circumstances described above, not only high reliability is required for equipment (for example, transformers) that make up substations, but also high reliability is required for auxiliary equipment (for example, transformer cooling systems). Sex is required. For example, a transformer cooling system that forms an underground substation is required to have high reliability because the stop of the cooling system is directly connected to the stop of the transformer (self-damage due to heat).

  In addition to being installed in urban areas where electricity demand is high, underground substations are installed on the basement floor of buildings, so heat generated in large quantities by transformers is difficult to dissipate. It is necessary to forcibly release heat from the underground floor to the outside (above ground), and the cooling facilities of underground substations tend to be larger and more complex than substations installed outdoors.

  A general underground substation cooling facility system exchanges heat generated in a transformer in the process of chilled water becoming hot water in a primary cooler installed in the transformer, and then heat from the primary cooler (primary cooling). The cooling water after the heat exchange in the cooler is sent to the secondary cooler by the circulating water pump, and the heat is exchanged in the process where the hot water becomes cold water by the secondary cooler. As an example of cooling equipment for substation equipment that employs the above-described structure, for example, a cooling system described in Japanese Patent Application Laid-Open No. 2001-91189 is known (for example, see Patent Document 1).

  In the transformer cooling system for an underground substation described in the cited reference 1, a wet cooler such as a cooling tower or a dry cooler is used as a secondary cooler. A cooling tower that can also be used as a dry cooler, that is, a cooler that can be used as both a dry cooler and a wet cooler, may be used as a secondary cooler.

  When a cooling tower is used as a wet cooler, the circulating water after absorbing the heat of the transformer, which is the object to be cooled, is introduced into the cooling tower, and the cooling fan (cooling air) inside the cooling tower is inside the cooling tower. ) And watering pump (spray water). Examples of the cooling tower include an open-type cooling tower having high versatility and a closed-type cooling tower that can suppress the contamination of circulating water.

JP 2001-91189 A

  In the transformer cooling system for an underground substation described in the above cited reference 1, a cooling tower is used as a cooling facility for the transformer, and any of an open cooling tower and a closed cooling tower is adopted. Even a large amount of water is required. More specifically, since the open type cooling tower is cooled by using latent heat of evaporation when the circulating water is directly opened to the atmosphere and evaporated, a large amount of water is used inside the cooling tower. In addition, the closed cooling tower sprays sprayed water directly on the heat exchange section through which the circulating water is passed and cools it using this latent heat of vaporization. Used for.

  In the case of underground substations that use cooling towers as the cooling equipment for transformers, although depending on the scale of the facility, the water charge required to operate the cooling equipment is tens of millions to several years per year for large facilities. In order to reach 100 million yen, there is a need to reduce the water charge, that is, to save water.

  In addition, considering the occurrence of large-scale disasters such as earthquakes directly below the Tokyo metropolitan area, which have been warned recently, there is a high possibility that water supply will be cut off at the time of disasters such as earthquakes directly below the Tokyo metropolitan area. It is expected that it will take a considerable number of days to recover. Therefore, transformer cooling systems for underground substations that require a large amount of water have the risk of stopping cooling facilities and eventually stopping underground substations, and it is necessary to reduce the risk of stopping such cooling facilities as much as possible. Yes. From such a background, it is desirable that the transformer cooling system of the underground substation is a transformer cooling system capable of continuously cooling the transformer without using water as much as possible.

  On the other hand, if a dry-type cooler that does not use a cooling tower is used as a cooling facility for the transformer, the above problem seems to be solved. However, since the dry cooler does not use water as compared with the wet cooler, the large latent heat possessed by water cannot be used. The cooling capacity of the wet cooler is proportional to the temperature difference between the cooling water temperature and the wet bulb temperature, while the cooling capacity of the dry cooler is proportional to the temperature difference between the cooling water temperature and the dry bulb temperature, which is It becomes smaller than the case of the vessel. For these reasons, the dry cooler is inefficient in heat exchange, and in order to exchange heat with the same amount of heat, a larger heat transfer area is required than in the wet cooler, and there is a problem that the apparatus is enlarged. Therefore, in general, the capacity of the transformer is large and the cooling capacity of the cooling facility is large, and in an urban area where the installation area is small, it is not a simple matter to replace the cooler with a dry-type cooler. It is necessary that the cooling equipment can be installed inside.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a transformer cooling system and a transformer cooling method for an underground substation having a cooling facility that uses water as much as possible and saves space. To do.

In order to solve the above-described problems, a transformer cooling system for an underground substation according to an embodiment of the present invention is provided on a path through which circulating water circulates, and is installed in the underground substation by exchanging heat with the circulating water. The primary cooling means for removing heat generated from the transformer to be removed from the transformer and the primary cooling means are installed on a path where the circulating water circulates at a position away from the primary cooling means and passes through the primary cooling means. Secondary cooling means for cooling the hot water as the later circulating water, and the secondary cooling means is capable of performing a dry operation by blowing air without using water for cooling at a high temperature and high load. Dry cooling means, the circulating water passing between the dry cooling means and the primary cooling means, and cooling for high temperature and high load that can exchange heat after the dry cooling means and before the primary cooling means before with the use of water And a least one wet cooling means wet operable by supplying air by a separate blower and the blower dry cooling means, wherein the dry cooling means and the wet cooling means is formed independently, the dry cooling The means is normally cooled, and the wet cooling means is configured to be preliminarily cooled in addition to the dry cooling means only when the cooling capacity is further increased .

In order to solve the above-described problem, a transformer cooling method for an underground substation according to an embodiment of the present invention is provided on a path through which circulating water circulates, and is installed in the underground substation by exchanging heat with the circulating water. The primary cooling means for removing heat generated from the transformer to be removed from the transformer and the primary cooling means are installed on a path where the circulating water circulates at a position away from the primary cooling means and passes through the primary cooling means. Secondary cooling means for cooling the hot water as the later circulating water, and the secondary cooling means is capable of performing a dry operation by blowing air without using water for cooling at a high temperature and high load. Dry cooling means, the circulating water passing between the dry cooling means and the primary cooling means, and cooling for high temperature and high load after the dry cooling means and heat exchange before and after the primary cooling means wherein with the use of water The blower of Formula cooling means and at least one wet cooling means wet operable by supplying air by a separate blower, wherein the dry cooling means and the wet cooling means is formed independently, the dry cooling means Of the underground substation , wherein the wet cooling means is configured to be preliminarily cooled in addition to the dry cooling means only when the cooling capacity is further increased . A transformer cooling method for an underground substation using a transformer cooling system, based on the temperature of the circulating water measured, during normal operation that is at the high temperature and high load or not at the high temperature and high load If the determination result is during the normal operation, the step of setting the dry cooling means to the operating state and the wet cooling means to the stop state, and the determination result is the high level Every time when a high load, the the dry cooling means and the operating state, characterized by comprising the steps of the wet cooling means and the operating state.

  According to the present invention, it is possible to greatly reduce the amount of water used in the cooling facility for cooling the object to be cooled.

The system block diagram which showed roughly the transformer cooling system of the underground substation which concerns on the 1st Embodiment of this invention, and its cooling system. The processing flowchart which shows the operation control procedure in the transformer cooling system of the underground substation which concerns on embodiment of this invention. The more detailed process flow figure of the cooler recommendation operation state judging step (Step S5) in the operation control procedure in the transformer cooling system of the underground substation concerning the embodiment of the present invention (when the operation stage is four stages). Explanatory drawing (graph) which shows the relationship between a cooling air temperature and the load factor in the wet bulb temperature over 27 degreeC, and thermal performance. The more detailed process flow figure of the cooler recommendation operation state judging step (Step S5) in the operation control procedure in the transformer cooling system of the underground substation concerning the embodiment of the present invention (when the operation stage is three stages). The system block diagram (1st Example) which showed schematically the transformer cooling system of the underground substation which concerns on the 2nd Embodiment of this invention, and its cooling system. The system block diagram (2nd Example) which showed schematically the transformer cooling system of the underground substation which concerns on the 2nd Embodiment of this invention, and its cooling system. The system block diagram which showed roughly the transformer cooling system of the underground substation which concerns on the 3rd Embodiment of this invention, and its cooling system. The system block diagram (1st Example) which showed schematically the transformer cooling system of the underground substation which concerns on the 4th Embodiment of this invention, and its cooling system. The system block diagram (2nd Example) which showed schematically the transformer cooling system of the underground substation which concerns on the 4th Embodiment of this invention, and its cooling system.

  Hereinafter, an underground substation transformer cooling system (hereinafter referred to as an “underground substation transformer cooling system”) and a transformer cooling method according to an embodiment of the present invention will be described with reference to the drawings.

  The underground substation transformer cooling system according to the embodiment of the present invention is different in cooling equipment from the conventional underground substation transformer cooling system. First, the cooling equipment of the underground substation transformer cooling system according to the embodiment of the present invention will be outlined.

  Underground substation substation cooling system cooling capacity of the cooling facility is designed so that 100% of the calorific value of all main units (cooled bodies) such as transformers in each bank can be cooled even in summer. It is common. However, the load factor of a transformer or the like in an underground substation is usually 60% or less, and generally about 80% at the maximum. In addition, since the design is based on the highest outdoor temperature in summer (for example, dry bulb temperature 40 ° C., wet bulb temperature 27 ° C. as an example), the total annual operation time (365 days × 24 hours = 8760 hours), the outside air temperature reaches the maximum temperature for a very short time (about 30 hours, about 0.3%).

  Therefore, it is considered that the load at the underground substation is almost never operated at 100% of the design value, and that the time when the outside air temperature exceeds the design value is negligible (about 0.3%). For example, as a substantial operation, even if the cooling capacity of the cooling equipment of the substation transformer cooling system is about 60% of the design value, the operation of the underground substation can be substantially covered.

  In view of the above circumstances, the cooling facility for the substation transformer cooling system according to the embodiment of the present invention is operated in a situation where the outside air temperature is low and the load on the underground substation is low (the load factor is approximately 60% or less) (hereinafter, Switching between “normal operation” and operation in the summer when the outside air temperature is high and the load on the underground substation is high (load factor is generally over 60%) (hereinafter referred to as “high load operation”). It is configured as a free cooling facility. In addition, water can be saved significantly by adopting a configuration that does not use water during normal operation, which occupies most of the year (limits the use of water during high-load operation).

  On the other hand, in the configuration other than the cooling facility, there is no substantial difference between the underground substation transformer cooling system and the conventional underground substation transformer cooling system according to the embodiment of the present invention, and the cooling system is also circulated. Since there is a common point in circulating water, there is no substantial difference in the operation other than cooling equipment. Therefore, in each embodiment to be described later, the cooling facility of the underground substation transformer cooling system will be mainly described. In general, underground substations in urban areas have a three-bank configuration. From the viewpoint of simplifying the description, a cooling system and a cooling system for one bank will be described.

[First Embodiment]
FIG. 1 shows an underground substation transformer cooling system (hereinafter referred to as “first underground substation transformer cooling system”) which is an example of an underground substation transformer cooling system according to the first embodiment of the present invention. This is a system schematic diagram schematically showing a cooling system 30 centering on a cooling facility of 10A (one bank is shown in FIG. 1).

  In FIG. 1, from the viewpoint of simplifying the drawing, the illustration of the control device that controls the operation of each device of the circulating water pump 31 and the secondary cooling means 22A (although it actually exists) is omitted. ing. Further, the illustration of the control device is also omitted in FIGS.

  The cooling system 30 in the first underground substation transformer cooling system 10 </ b> A is a system in which circulating water (cooling water) cooled by the cooling facility is circulated by the circulating water pump 31. That is, in the first underground substation transformer cooling system 10A, the circulating water flows cyclically through a flow path configured by connecting the primary cooling means 21, the circulating water pump 31, and the secondary cooling means 22A. ing.

  The primary cooling means 21 (heat exchanger) has a function of radiating heat generated by the transformer (cooled body) 1 to the circulating water. The primary cooling means 21 (heat exchanger) removes heat generated by the transformer 1 from the transformer 1 by exchanging heat with circulating water having a temperature lower than that of the transformer 1.

  The secondary cooling means 22A is provided at a position away from the primary cooling means 21, and has a function of cooling the circulating water (hot water) after passing through the primary cooling means 21. The secondary cooling means 22A cools the circulating water that has become hot water by the heat generated by the transformer 1 by radiating the heat of the circulating water (heat exchange). The circulating water that has become cold water is circulated again from the secondary cooling means 22A to the primary cooling means 21 (heat exchanger) on the transformer 1 side.

  The cooling system 30 is provided with a makeup water tank 32 that stores makeup water and a thermometer 35 that measures the temperature of the circulating water.

  The makeup water tank 32 appropriately supplies the stored makeup water to the cooling system 30 and the wet cooler 43.

  The thermometer 35 is installed, for example, on the side (inlet side) where the circulating water flows into the primary cooling means 21, and measures the temperature of the circulating water flowing into the primary cooling means 21. The temperature information (circulated water temperature TE) acquired by the thermometer 35 is used for operation control of the secondary cooling means 22A.

  Subsequently, the secondary cooling means 22A in the first underground substation transformer cooling system 10A will be described.

  The secondary cooling means 22A includes at least one dry cooler 41 as a dry cooling means and at least one wet cooler 43 such as a cooling tower as a wet cooling means, and is configured to cool the circulating water. . In the secondary cooling means 22A, the dry-type cooler 41 is regularly (mainly) used as a means for heat exchange with the circulating water passing through the primary cooling means 21 to further increase the cooling capacity during high loads in summer. Wet cooler 43 as means for exchanging heat with circulating water passing between dry cooler 41 and primary cooling means 21 using water for cooling only when necessary (during high temperature and high load) Is used preliminarily.

  The dry cooler 41 includes a heat transfer section 411 through which circulating water (hot water) flows. Inside the dry cooler 41, the air 3 introduced from the outside is air-cooled by ventilating the heat transfer section 411. Therefore, in the dry cooler 41, heat exchange is performed between the circulating water and the air 3 through the heat transfer section 411, and the circulating water is radiated and cooled by the air 3, while the air 3 receives heat from the circulating water. Absorb (heat absorption) and warm. The air 3 warmed by ventilating the heat transfer section 411 is exhausted to the outside of the dry cooler 41.

  The wet cooler 43 includes, for example, a sealed type including a heat transfer unit 431 through which circulating water flows and a water spray unit 433 that sprays the internal stored water pumped up by the water spray pump 432 to the heat transfer unit 431 as spray water. Consists of cooling towers. In addition, although the following description is an example in case the wet cooler 43 is a type in which dry operation (operation state in which the blower is on (start) and the watering pump is off (stop)) is possible, the wet cooler 43 is wet. The cooler 43 may be a type incapable of dry operation.

In the secondary cooling means 22A, a wet cooler 43 is connected in series after the dry cooler 41,
(1) The blower of the dry cooler 41 is only off (stopped) water flow,
The fan of the wet cooler 43 is turned off (stopped) only, the watering pump is turned off (stopped),
(2) The blower of the dry cooler 41 is on (started),
The fan of the wet cooler 43 is turned off (stopped) only, the watering pump is turned off (stopped),
(3) The blower of the dry cooler 41 is on (started up),
The fan of the wet cooler 43 is on (start), the watering pump is off (stop), and (4) the fan of the dry cooler 41 is on (start),
The fan of the wet cooler 43 is on (start), the watering pump is on (start),
The cooling stage (operating state) is switched to the four stages.

  The switching of the cooling stage in the secondary cooling means 22A is performed according to the temperature of the circulating water flowing through the primary cooling means 21, that is, the circulating water temperature TE acquired by the thermometer 35. As it becomes higher, the numbers in parentheses (1) → (2) → (3) → (4) are switched from the small to the large cooling stage. On the other hand, when the circulating water temperature TE becomes low, the numbers in parentheses (4) → (3) → (2) → (1) are switched from the large to the small cooling stage.

  As described above, the secondary cooling unit 22A appropriately switches the operation state of the dry cooler 41 and the wet cooler 43 according to the temperature of the circulating water (circulating water temperature TE), so that an appropriate cooling stage is selected. Circulating water flowing through the primary cooling means 21 is continuously cooled.

  FIG. 2 shows an operation showing an operation control procedure (cooling stage switching procedure) of the first underground substation transformer cooling system 10A as an example of an operation control procedure in the transformer cooling system of the underground substation according to the embodiment of the present invention. FIG. FIG. 3 is a more detailed process flow diagram of the cooler recommended operation state determination step (step S5) in the operation control procedure (cooling stage switching procedure: FIG. 2).

  Note that T1, T2, and T3 shown in FIG. 3 are threshold values (set temperatures) for determining whether to move the operating state of the cooler from the stopped state (off) to the operating state (on), and each of them is a dry cooler. 41 (FIG. 1) blower start determination threshold value, wet cooler 43 (FIG. 1) blower start determination threshold value, and wet cooler 43 water spray pump start determination threshold value. The relationship between the threshold values T1, T2, and T3 is T1 <T2 <T3. Further, α, β, and γ shown in FIG. 3 are OFF determination setting values (arbitrary real numbers that are equal to or greater than 0) that are set for OFF determination that shifts the operating state of the cooler from the operating state to the stopped state. .

  The operation control procedure (steps S1 to S8) illustrated in FIG. 2 is executed by the control device, and the circulating water pump operation transition process (steps S1 and S2), the cooling water temperature control process (steps S3 to S8), and It comprises.

  The processing step of the operation control procedure is started when the cooling of the transformer as the object to be cooled starts. In the circulating water pump operation transition step (steps S1 and S2), the circulating water pump is shifted to the operating state.

  That is, it is determined whether or not the circulating water pump is operated (step S1), and when the circulating water pump has not yet started operation (NO in step S1), the circulating water pump 31 is activated. The operation is started (step S2), and the circulating water pump operation transition process (steps S1 and S2) is completed.

  On the other hand, when the circulating water pump 31 is already in operation (YES in step S1), the circulating water pump operation transition process (steps S1 and S2) is completed. When the circulating water pump operation transition process is completed, the processing flow of the operation control procedure proceeds to the next processing step (step S3).

  In the cooling water temperature control process (step S3 to step S8), the thermometer 35 (FIG. 1) acquires the circulating water temperature TE (step S3), and the secondary cooling means 22A (FIG. 1) is obtained according to the acquired circulating water temperature TE. 1), that is, the operating states of the dry cooler 41 (FIG. 1) and the wet cooler 43 (FIG. 1) are switched (steps S4 to S7).

  After the circulating water temperature TE is acquired (step S3), first, the current operation state of the dry cooler 41 and the wet cooler 43 is confirmed (step S4). The current operation state of the dry cooler 41 and the wet cooler 43 is monitored and grasped by the control device. When the confirmation of the current operation state of the dry cooler 41 and the wet cooler 43 is completed, a cooler recommended operation state determination step is subsequently performed (step S5).

  In the cooler recommended operation state determination step, it is determined which cooling stage (operation stage) the dry cooler 41 and the wet cooler 43 should be performed (recommended operation state) from the obtained circulating water temperature TE (detailed determination). The flow will be described later). More specifically, it is determined which of the four cooling stages (operational stages) (1) to (4) should be recommended. Here, for convenience of explanation, the four cooling stages (operation stages) (1) to (4) described above are hereinafter referred to as “first operation stage”, “second operation stage”, and “third stage”, respectively. And “fourth operation stage”.

  In the cooler recommended operation state determination step (step S5), when it is determined which operation stage the dry-type cooler 41 and the wet-type cooler 43 should be in, the confirmation result of step S4, that is, the current dry-type cooling is performed. The operation state of the cooler 41 and the wet cooler 43 is compared with the determination result of step S5, that is, the recommended operation state of the dry cooler 41 and the wet cooler 43 (any one of the first to fourth operation stages). (Step S6).

  Here, when the operation state matches (in the case of YES in step S6), it is confirmed whether or not the transformer 1 is stopped (step S8), and when it is stopped (in the case of YES in step S8). On the other hand, when the operation control procedure is finished (END), while being in operation (NO in step S8), the processing flow of the cooling water temperature control process returns to step S3, and the processing steps after step S3 are executed. Is done.

  On the other hand, when the operation state does not match (NO in step S6), the operation stage of the dry cooler 41 and the wet cooler 43 is switched to the operation stage determined in step S5 by the control device. That is, the operation state of the dry cooler 41 and the wet cooler 43 is switched (step S7). When the switching of the operation state is completed, the processing flow of the cooling water temperature control process proceeds to step S8, and the processing steps after step S8 are executed.

  Then, with reference to FIG. 3, the more detailed process content (step S501-step S514: FIG. 3) of a cooler recommended operation state determination step (step S5: FIG. 2) is demonstrated.

  The cooler recommended operation state determination step (steps S501 to S514) is a processing step for determining an operation stage to be recommended, in general terms, and maintains the current operation stage in the cooling water temperature control step (FIG. 2). This is a step of providing information for determining whether or not (should be switched).

  In the cooler recommended operation state determination step (ENTER), first, when the current operation stage of the dry cooler 41 (FIG. 1) and the wet cooler 43 (FIG. 1) is the first operation stage (in step S501). In the case of YES), the circulating water temperature TE is compared with a temperature (threshold value) T1 set as a temperature for turning on the blower of the dry cooler 41 (step S502).

  Here, when the circulating water temperature TE is less than T1, that is, when TE ≧ T1 is not satisfied (NO in step S502), the operation stage of the dry cooler 41 and the wet cooler 43 should be the first operation stage. Is determined (first operation stage is recommended) (step S503). On the other hand, when the circulating water temperature TE is equal to or higher than T1, that is, when TE ≧ T1 is satisfied (YES in step S502), it is determined that the operation stage of the dry cooler 41 and the wet cooler 43 should be the second operation stage. (Recommended second operation stage) (step S504). When the recommended operation stage is determined (steps S503 and S504), the cooler recommended operation state determination step is completed (RETURN). In addition, after completion of the cooler recommended operation state determination step, step S6 shown in FIG. 2 is executed.

  Subsequently, if the current operation stage of the dry cooler 41 (FIG. 1) and the wet cooler 43 (FIG. 1) is the second operation stage (NO in step S501 → YES in step S505), circulation The water temperature TE is compared with the temperature (threshold value) T1-α set as the temperature at which the blower of the dry cooler is turned off (step S506).

  Here, when the circulating water temperature TE is equal to or lower than T1-α, that is, when TE ≦ T1-α is satisfied (YES in step S506), the operation stages of the dry cooler 41 and the wet cooler 43 are the first operation stages. The first operation stage is recommended (step S503), and the cooler recommended operation state determination step is completed (RETURN).

  On the other hand, the circulating water temperature TE is higher than T1-α and is lower than a temperature (threshold value) T2 set as a temperature at which the blower of the wet cooler 43 is turned on, that is, TE ≦ T1-α is not satisfied, and TE If ≧ T2 is not satisfied (NO in step S506 → NO in step S507), it is determined that the operation stage of the dry cooler 41 and the wet cooler 43 should be the second operation stage (the second operation stage is (Recommended) (step S504), and the cooler recommended operation state determination step is completed (RETURN).

  Further, when the circulating water temperature TE is equal to or higher than T2 exceeding T1-α, that is, TE ≦ T1-α is not satisfied and TE ≧ T2 is satisfied (NO in step S506 → YES in step S507), dry cooling is performed. It is determined that the operation stage of the vessel 41 and the wet cooler 43 should be the third operation stage (the third operation stage is recommended) (step S508). When the recommended operation stage is determined (step S508), the cooler recommended operation state determination step is completed (RETURN).

  Subsequently, when the current operation stage of the dry cooler 41 (FIG. 1) and the wet cooler 43 (FIG. 1) is the third operation stage (NO in step S501 → NO in step S505 → YES in step S509). ), The circulating water temperature TE is compared with a temperature (threshold value) T3 set as a temperature at which the watering pump of the wet cooler 43 is turned on (step S510). Here, when the circulating water temperature TE is less than T3, that is, when TE ≧ T3 is not satisfied (NO in step S510), the circulating water temperature TE is further set as a temperature at which the fan of the wet cooler is turned off. It is compared with the set temperature (threshold value) T2-β (step S511).

  As a result of the comparison, when the circulating water temperature TE is equal to or lower than T2-β, that is, when TE ≦ T2-β is satisfied (NO in step S510 → YES in step S511), the dry cooler 41 and the wet cooler It is determined that the operation stage 43 should be the second operation stage (the second operation stage is recommended) (step S504), and the cooler recommended operation state determination step is completed (RETURN). On the other hand, when circulating water temperature TE exceeds T2-β, that is, when TE ≦ T2-β is not satisfied (NO in step S510 → NO in step S511), dry cooler 41 and wet cooler 43 Is determined to be the third operation stage (the third operation stage is recommended) (step S508), and the cooler recommended operation state determination step is completed (RETURN).

  As a result of comparing the circulating water temperature TE with T3, if the circulating water temperature TE is equal to or higher than T3 (YES in step S510), the operation stages of the dry cooler 41 and the wet cooler 43 are set to the fourth. (4th operation stage is recommended) (step S512), and the cooler recommended operation state determination step is completed (RETURN).

  Subsequently, when the current operation stage of the dry cooler 41 (FIG. 1) and the wet cooler 43 (FIG. 1) is the fourth operation stage (NO in step S501 → NO in step S505 → NO in step S509) ), The circulating water temperature TE is compared with a temperature (threshold value) T3-γ set as a temperature at which the watering pump of the wet cooler 43 is turned off (step S513). Here, when the circulating water temperature TE is equal to or lower than T3-γ, that is, when TE ≦ T3-γ is satisfied (YES in step S513), the operation stages of the dry cooler 41 and the wet cooler 43 are the third operation stages. The third operation stage is recommended (step S508), and the cooler recommended operation state determination step is completed (RETURN).

  On the other hand, when the circulating water temperature TE is higher than T3-γ, that is, when TE ≦ T3-γ is not satisfied (NO in step S513), the operation stages of the dry cooler 41 and the wet cooler 43 are set to the fourth. (4th operation stage is recommended) (step S512), and the cooler recommended operation state determination step is completed (RETURN).

  Next, the cooling capacity of the cooling equipment (mainly secondary cooling means) and the cooling capacity of the wet cooling means in the underground substation transformer cooling system according to the embodiment of the present invention, and the underground substation according to the embodiment of the present invention The usefulness of the transformer cooling system will be explained.

  In the substation transformer cooling system according to the embodiment of the present invention, the operation state of the secondary cooling means is dry operation at normal load (dry cooling means on, wet cooling means off), and wet operation at high loads. (The dry cooling means is on and the wet cooling means is on). For example, in the first underground substation transformer cooling system 10A (FIG. 1), during normal load, the dry cooler 41 is turned on and the wet cooler 43 is turned off. On the other hand, when the load is high, the wet cooler 43 is turned on in addition to the dry cooler 41.

  Further, in the substation transformer cooling system according to the embodiment of the present invention, the outside air temperature in the hottest summer season is set as the design temperature, and the cooling capacity (cooling capacity) of the dry cooling means as the secondary cooling means and the wet cooling means. ) Is determined. The cooling capacity of the dry cooling means and the cooling capacity of the wet cooling means are determined so that the total cooling capacity is equal to or greater than the amount of heat generated during 100% load operation of the transformer 1 (FIG. 1).

  The design temperature of the dry cooler 41 is based on the dry bulb temperature in the hottest midsummer of the place where the underground substation is installed. For example, in Tokyo and the like, the design temperature is a dry bulb temperature of 40 ° C.

  The design temperature of the wet cooler 43 is based on the wet bulb temperature at the hottest midsummer time of the place where the underground substation is installed. For example, the highest wet bulb temperature is adopted in a predetermined period such as the past 30 years. Can be determined. For example, in Tokyo and the like, a wet bulb temperature of 27 ° C. is set as the design temperature.

  Further, the cooling capacity of the secondary cooling means 22A, that is, the total cooling capacity of the cooling capacity of the dry-type cooler 41 and the cooling capacity of the wet-type cooler 43 is equal to or greater than the amount of heat generated during 100% load operation of the transformer 1. To be determined. In addition, the cooling capacity of the dry cooler 41 is set to a cooling capacity that allows 100% load operation of the transformer 1 only by operating the dry cooler 41 under the condition of a dry bulb temperature of 26 ° C., which is lower than the design temperature.

Subsequently, when the first underground substation transformer cooling system 10A (FIG. 1) that is an example of the underground substation transformer cooling system according to the embodiment of the present invention exceeds the cooling air temperature (inlet air temperature), To what extent the load factor can be handled only by dry operation, the utility of the underground substation transformer cooling system according to the embodiment of the present invention will be described.
In the description, one model is set for the dry cooler 41 and the transformer (cooled body). In other words, the location of the underground substation is Tokyo, and the heat exchanger rated logarithm average temperature difference of the dry cooler 41 and the iron loss ratio of the transformer (cooled body) 1 are set as follows.

<Dry cooler 41>
Cooling air temperature (inlet air temperature) Tai: 26 ° C (Tokyo's highest wet bulb temperature)
Outlet air temperature Tao: Tao = Tai + 13 = 26 + 13 = 39 ° C.
Circulating water (cooling water) inlet temperature Twi: 48 ° C
Circulating water (cooling water) outlet temperature Two: 58 ° C
Heat exchanger rated logarithm average temperature difference = {(58-39)-(48-26)} / ln {(58-39) / (48-26)}
= 20.46 ° C

<Transformer 1>
Capacity: 300MVA (gas insulated transformer)
Rated iron loss (no load loss): 120kW
Rated copper loss (load loss): 1710 kW
Rated loss: 1830kW
Iron loss ratio: 120/1830 = 0.0656

  Using the fact that the heat transfer performance of the dry cooler 41 is proportional to the logarithm average temperature difference, when the cooling air temperature (wet bulb temperature 26 ° C.) is exceeded, what is the load factor of the transformer 1 under the above setting conditions It will be described whether it is possible to cope with only the dry cooler 41 (dry operation) of the set conditions until

  FIG. 4 is an explanatory diagram (graph) showing the relationship between the cooling air temperature (inlet air temperature) and the load factor and heat transfer performance when the dry bulb temperature exceeds 26 ° C., derived from the equations (1) to (6). It is. In addition, the code | symbol L1 is a graph which shows a load factor, the code | symbol L2 is a graph which shows heat-transfer performance, and the numerical value of 26 degreeC is set to 1 in any graph of L1 and L2.

  The heat transfer performance decreases as the temperature rises above 26 ° C., but in the graph L1 shown in FIG. 4, the American Society of Heating, Refrigerating and Air Conditioning (ASHRAE) in Tokyo where the underground substation is installed. Heating, Refrigerating and Air-Conditioning Engineers), which is the design standard for cooling, has a yearly excess risk factor of 0.4%, average matched dry bulb temperature (0.4% MCDB) of 33.2 ° C, and the load factor is about 80%. is there. Although the load factor differs somewhat at each substation, it is generally said that the load is 60-80%. Therefore, even in dry bulb temperature of 33.2 ° C, it is loaded by dry operation (operation only by dry cooler 41). Since it is possible to deal with the amount of heat generated at a rate of 80%, the cooling of the transformer 1 can be continued most of the time without operating the wet cooler 43 (wet operation) throughout the year.

  If the wet operation is substantially 0 (zero), the replenishment moisture used in the wet cooler 43 can be reduced to almost 0 (zero), that is, 100% can be saved. It should be noted that the wet cooler 43 starts the wet cooler 43 even when the air temperature condition is high (100%) and extremely high (40 ° C.), for example, when the load factor exceeds 80%. Thus, the transformer can be cooled within the design temperature. That is, the wet cooler 43 can be installed in the position of a preliminary (emergency) cooling means in preparation for an extremely rare case of high temperature and high load. Even if it is necessary to operate the wet cooler 43, its use is limited to an extremely short time in an emergency, so that blow-down water is not generated and sewage treatment is not required. Therefore, not only the water supply fee for makeup water but also the sewerage fee can be greatly reduced.

  Further, in the graph L2 shown in FIG. 4, for example, the heat transfer performance when designed under the condition of 0.4% MCDB (= dry bulb temperature 33.2 ° C.) that is the cooling design reference temperature of ASHRAE in Tokyo is dry. With respect to the heat transfer performance 1 at a sphere temperature of 26 ° C., it is 0.65, which is about 2/3. Therefore, when designed under the 0.4% MCDB condition, which is the cooling design reference temperature of ASHRAE, the heat transfer area required to dissipate the same amount of heat as compared with the design under the dry bulb temperature of 26 ° C. is about 1.5 times. Therefore, when designed under the condition of a dry bulb temperature of 26 ° C, the same amount of heat should be dissipated in about 2/3 of the equipment area when designed under the condition of ASHRAE cooling 0.4% MCDB (dry bulb temperature 33.2 ° C). Can do.

  Further, as is apparent from FIG. 4, when designed under the condition of 40 ° C., the heat quantity at 40 ° C. is about 1/3 of that at 26 ° C. That is, the installation area of the dry cooler 41 designed under the 26 ° C. condition is about 1/3 of the installation area when designed under the 40 ° C. condition. This is an extremely large installation area reduction effect.

  Thus, the underground substation according to the embodiment of the present invention that can cope with the dry operation without performing the wet operation on the heat generated at the load factor of 80% under the 0.4% MCDB condition that is the cooling design reference temperature of ASHRAE. Because the substation transformer cooling system can substantially reduce the amount of water used, not only can the yearly water bills (water and sewage bills) be significantly reduced, but also water breaks off when a large-scale disaster occurs. Even if it occurs, it can be said that it is extremely useful in that the cooling of the transformer 1 can be continued.

  According to the first underground substation transformer cooling system 10A and the first underground substation transformer cooling method, the operation of the wet cooler 43 can be limited to a very short time (the outside air temperature and the transformer). Depending on the load, it is possible to reduce the operating time to zero), so that it is possible to save water significantly (up to 100%) compared to the conventional case. Therefore, it is possible to significantly reduce (up to 100%) the cost of water (water supply and sewerage) required when operating the first underground substation transformer cooling system 10A.

  In this description, the operation time of the wet cooler 43 has been discussed. However, the wet cooler 43 can be operated dry (the blower is on and the watering pump is off), and the amount of heat that exceeds the cooling heat amount of the dry cooler 41. Is small, the wet cooler 43 can be cooled by a dry operation, and the amount of water used can be further reduced by the cooling by the dry operation.

  In the first underground substation transformer cooling system 10A, since the water required for operating the secondary cooling means 22A is almost zero, even if a water outage occurs due to the occurrence of a large-scale disaster, Cooling of the vessel 1 can be continued. In the first underground substation transformer cooling system 10A, it is necessary to operate the wet cooler 43 at a high load that may occur in the unlikely event that the load factor exceeds 60%, but a large-scale disaster occurs. In such a situation that water breakage occurs, the load factor is assumed to be lower than normal. Therefore, as long as the dry cooler 41 is operated without operating the wet cooler 43, Sufficient cooling capacity capable of continuing cooling of the transformer 1 can be ensured.

  Further, in the first underground substation transformer cooling system 10A, since the operation required time of the wet cooler 43 can be limited to a limited time throughout the year, the scale (water scale) adhesion on the wet cooler 43 almost occurs. Therefore, maintainability such as cleaning becomes simple. Furthermore, since the wet cooler 43 is not operated for a long period of time (regularly), it is not necessary to take preventive measures for legionellosis, and the labor and cost required for the preventive measures for legionellosis can be reduced.

  Furthermore, in the first underground substation transformer cooling system 10A, the facility area of the secondary cooling means 22A can be significantly reduced as compared with the case of only the dry cooler 41 (as an example, it can be reduced to about 2/3). ). Therefore, even in underground substations in urban areas where it is generally difficult to secure a large installation space, if the same installation space as the current situation can be secured, the cooling of the first underground substation transformer can be performed not only at the time of new installation but also at the time of renovation. The system 10A can also be applied.

  In the first underground substation transformer cooling system 10A, the wet cooler 43 is not limited to the type of type that always performs wet operation, and may be any type that allows wet operation. For example, a cooling tower that can be operated in a dry mode (wet chiller that can be operated in a dry manner while being based on a wet operation) or a dry chiller that can be operated in a dry mode while being based on a dry operation (for example, described later) 8 and 9 can be introduced as the wet cooler 43 of the secondary cooling means 22A.

  Further, in the first embodiment of the present invention, the case where the wet type cooler 43 is a closed type is illustrated and described in FIG. 1, but an open type wet type cooler is used instead of the closed type wet type cooler 43. Even if 47 (FIG. 8) is applied, the first underground substation transformer cooling system 10A can be operated in substantially the same manner. In the case of applying the open type wet cooler 47, assuming that both the blower and the watering pump are started (on) or stopped (off), it is assumed that there are three operation stages. The basic logic of the determination is the same for the case where is in three stages.

  In the case where the operation stage is three stages, in the processing flow of the cooler recommended operation state determination step (step S501 to step S514) shown in FIG. Steps related to the threshold T3 (steps S509, S510, S512, and S513) may be omitted, and the processing step subsequent to NO in step S505 may be replaced with step S509 instead of step S509. More specifically, it is as shown in FIG.

[Second Embodiment]
FIG. 6 is an example of an underground substation transformer cooling system (hereinafter, “second underground substation transformer cooling system”) that is an example of an underground substation transformer cooling system according to the second embodiment of the present invention. FIG. 6 is a system schematic diagram (first embodiment) schematically showing a cooling system 30 centering on a cooling facility of 10B (one bank is shown in FIG. 6).

  Although the second underground substation transformer cooling system 10B is different from the first underground substation transformer cooling system 10A in that the secondary cooling means 22B is provided instead of the secondary cooling means 22A, Other points are not substantially different. Therefore, in the present embodiment, differences from the first underground substation transformer cooling system 10A will be mainly described, and components that are not substantially different from the components of the first underground substation transformer cooling system 10A. Are denoted by the same reference numerals and description thereof is omitted.

  The cooling system 30 in the second underground substation transformer cooling system 10 </ b> B is a system in which circulating water (cooling water) cooled by the cooling facility is circulated by the circulating water pump 31. That is, the circulating water flows cyclically through a flow path configured by connecting the primary cooling means 21, the circulating water pump 31, and the secondary cooling means 22B.

  Similar to the secondary cooling means 22A, the secondary cooling means 22B has a function of cooling circulating water (hot water) after passing through the primary cooling means 21, and includes at least one dry cooler 41 and dry cooling. A wet cooler 43 such as at least one cooling tower connected in series to the subsequent stage of the cooler 41, and at least one heat exchanger 45 provided in the previous stage of the wet cooler 43.

In the secondary cooling means 22B illustrated in FIG. 6, in the secondary cooling means 22B in which the dry cooler 41 and the heat exchanger 45 are provided in parallel, the open / close states of the valves 46a to 46d are switched during operation, and the dry Circulating water is introduced into the cooler 41 or the heat exchanger 45. The circulating water after passing through the dry cooler 41 or the heat exchanger 45 is introduced into the wet cooler 43 installed in the subsequent stage.

  The heat exchanger 45 is constituted by, for example, a plate heat exchanger, and circulating water (hot water) flowing through the circulation passage of the cooling system 30 is on the primary side, and water (cold water) as a refrigerant is on the secondary side. There is water. The heat exchanger 45 exchanges heat between circulating water (hot water) flowing on the primary side and cold water flowing on the secondary side. By heat exchange in the heat exchanger 45, the circulating water flowing on the primary side is deprived of heat and the temperature decreases, while the cold water flowing on the secondary side absorbs heat and the temperature rises. The water on the secondary side warmed by the heat exchanger 45 can be used for hot water supply or the like.

  Subsequently, an underground substation transformer cooling method using the second underground substation transformer cooling system 10B (hereinafter, referred to as “second underground substation transformer cooling method”) will be described.

  Although the second underground substation transformer cooling method is substantially the same as the steps to be performed although the system used differs from the first underground substation transformer cooling method, the first underground substation transformer cooling method is the same. With the description of the substation transformer cooling method, the description of the second underground substation transformer cooling method is omitted.

  According to the second underground substation transformer cooling system 10B and the second underground substation transformer cooling method, the first underground substation transformer cooling system 10A and the first underground substation transformer cooling method In addition to producing the same effect as above, the heat dissipated when the transformer 1 is cooled can be effectively used without wasting it.

  In the second underground substation transformer cooling system 10B, the secondary cooling means 22B is not necessarily limited to the configuration shown in FIG. In the secondary cooling means 22 </ b> B, it is only necessary that the heat exchanger 45 that dissipates the heat of the circulating water is installed at least before the wet cooler 43.

  FIG. 7 is a system schematic diagram (second diagram) schematically showing a cooling system 30 centering on a cooling facility (second bank is shown in FIG. 7) of the second underground substation transformer cooling system 10B. Example).

  The secondary cooling means 22B in the second underground substation transformer cooling system 10B performs heat exchange further upstream than the dry cooler 41 installed in the preceding stage of the wet cooler 43, for example, as shown in FIG. The vessel 45 may be installed in series. In addition to the example shown in FIG. 7, the heat exchanger 45 may be installed in series downstream of the dry cooler 41 and upstream of the wet cooler 43.

  When the dry cooler 41 and the heat exchanger 45 are installed in series, there is no need to additionally install the valves 46a to 46d as in the case of installing in parallel, and the advantage that the configuration can be simplified. There is.

[Third embodiment]
FIG. 8 shows an underground substation transformer cooling system (hereinafter referred to as “third underground substation transformer cooling system”) which is an example of an underground substation transformer cooling system according to the third embodiment of the present invention. This is a system schematic diagram schematically showing a cooling system 30 centering on a 10C cooling facility (in FIG. 8, one bank is shown).

  Although the third underground substation transformer cooling system 10C is different from the first underground substation transformer cooling system 10A in that the secondary cooling means 22C is provided instead of the secondary cooling means 22A, Other points are not substantially different. Therefore, in the present embodiment, differences from the first underground substation transformer cooling system 10A will be mainly described, and components that are not substantially different from the components of the first underground substation transformer cooling system 10A. Are denoted by the same reference numerals and description thereof is omitted.

  The cooling system 30 in the third underground substation transformer cooling system 10C includes circulating water (cooling water) in a flow path formed by connecting the primary cooling means 21, the circulating water pump 31, and the secondary cooling means 22C. ) In a circulating manner, it is configured similarly to the cooling system 30 of other underground substation transformer cooling systems such as the first underground substation transformer cooling system 10A.

  On the other hand, the cooling system 30 in the third underground substation transformer cooling system 10C has circulating water flowing through the main system in addition to the circulation channel (main system) through which the circulating water circulates through the primary cooling means 21. Is further provided with a circulation channel (sub system) different from the main system that dissipates (cools) this heat by heat exchange. That is, the cooling system 30 of the third underground substation transformer cooling system 10C includes two independent circulation channels (main system and sub system).

  Similar to the secondary cooling means 22A, the secondary cooling means 22C has a function of cooling the circulating water (hot water) after passing through the primary cooling means 21, and includes at least one dry-type cooler 41 and at least one A wet-type cooler 47 and a heat exchanger 48 are provided. The wet cooler 47, for example, pumps up the internal water with a watering pump 472 and sends it to the heat exchanger 48. After passing through the heat exchanger 48, the water is sprayed with the internal watering part 473 and directly opened to the atmosphere to evaporate. It consists of an open type cooling tower that cools using the latent heat of vaporization. Moreover, the heat exchanger 48 is comprised with a plate-type heat exchanger, for example.

  In the main system of the cooling system 30, the secondary cooling means 22C cools the circulating water (warm water) after passing through the primary cooling means 21 by dissipating heat between the dry cooler 41 and the primary side of the heat exchanger 48. . In addition, the secondary cooling means 22 </ b> C dissipates the circulating water of the secondary system that has absorbed heat from the circulating water of the main system on the secondary side of the heat exchanger 48 in the secondary system of the cooling system 48 with the wet cooler 47. And return to the heat exchanger 48.

  As described above, the third underground substation transformer cooling system 10C is different from the first underground substation transformer cooling system 10A in that the secondary cooling means 22C instead of the secondary cooling means 22A, more specifically, Since the open-type wet cooler 47 and the heat exchanger 48 are provided instead of the sealed wet cooler 43, the wet cooler as a cooling facility can be further reduced in size, which is advantageous in terms of ease of maintenance and cost. .

  Further, in the third underground substation transformer cooling system 10C, the cooling system 30 is separated into the main system through which the primary cooling means 21 passes and the sub system through which the wet cooler 47 passes, so that the first As in the case of the underground substation transformer cooling system 10A, it is possible to prevent the quality of the circulating water flowing through the main system from deteriorating.

  An underground substation transformer cooling method using the third underground substation transformer cooling system 10C (hereinafter referred to as "third underground substation transformer cooling method") is performed with different systems. Since the steps are substantially the same, the description of the third underground substation transformer cooling method is omitted with the description of the first underground substation transformer cooling method. In the third underground substation transformer cooling method, since the open type wet cooler 47 is used, the processing content of the cooler recommended operation state determination step is, for example, the same as the content shown in FIG. 5 described above. Become.

  According to the third underground substation transformer cooling system 10C configured as described above, and according to the third underground substation transformer cooling method, the first underground substation transformer cooling system 10A, and the first In addition to the same effects as the underground substation transformer cooling method, the maintenance is easier and the cost can be further reduced.

  Note that the above-described third underground substation transformer cooling system 10C is different from the first underground substation transformer cooling system 10A in that an open-type wet cooler 47 and a sealed wet-type cooler 43 are used. Although it is an example provided with the heat exchanger 48, Applying also to underground substation transformer cooling systems other than 10A of 1st underground substation transformer cooling systems, such as 2nd underground substation transformer cooling system 10B, for example. Can do.

[Fourth Embodiment]
FIG. 9 shows an example of an underground substation transformer cooling system (hereinafter referred to as “fourth underground substation transformer cooling system”) as an example of an underground substation transformer cooling system according to the fourth embodiment of the present invention. This is a system schematic diagram (first embodiment) schematically showing a cooling system 30 centering on a 10D cooling facility (one bank is shown in FIG. 9).

  Although the fourth underground substation transformer cooling system 10D is different from the first underground substation transformer cooling system 10A in that the secondary cooling means 22D is provided instead of the secondary cooling means 22A, Other points are not substantially different. Therefore, in the present embodiment, differences from the first underground substation transformer cooling system 10A will be mainly described, and components that are not substantially different from the components of the first underground substation transformer cooling system 10A. Are denoted by the same reference numerals and description thereof is omitted.

  The cooling system 30 in the fourth underground substation transformer cooling system 10 </ b> D is a system in which circulating water (cooling water) cooled by the cooling facility is circulated by the circulating water pump 31. That is, the circulating water flows cyclically through a flow path configured by connecting the primary cooling means 21, the circulating water pump 31, and the secondary cooling means 22D.

  The secondary cooling means 22D is similar to the secondary cooling means 22A in that it has a function of cooling the circulating water (hot water) after passing through the primary cooling means 21, but the configuration is different. For example, in the fourth underground substation transformer cooling system 10D shown in FIG. 9, the secondary cooling means 22D can be operated even if it is at least one wet type (wet operation is possible) (hereinafter referred to as “watering type”). This is referred to as a “dry cooler”.) 51. That is, the water spray type dry cooler 51 serves as both a dry cooling unit and a wet cooling unit in the secondary cooling unit 22D.

  For example, the water spray type dry cooler 51 is in contact with the heat transfer section 511 through which the circulating water (hot water) after passing through the primary cooling means 21 passes, and the air 3 introduced from the outside contacts the heat transfer section 511. A spray section (sprinkling section) 513 for spraying makeup water (cold water) supplied from the makeup water tank 32 through the spray water pump 37 and the valve 38 within a predetermined range in front (spraying into finer water droplets); Prepare.

  The water spray type dry cooler 51 acts as a dry cooling means of the secondary cooling means 22D when the spraying at the spraying section 513 is stopped, and is performed when the spraying at the spraying section 513 is performed. It acts as a wet cooling means for the next cooling means 22D. The spray unit 513 is not necessarily limited to the case of spraying fine water droplets (spraying), and may spray water without making it mist. This also applies to the spray unit 533 described later.

  Accordingly, the water spray type dry cooler 51 as the dry cooling means is substantially the same as the wet cooler 43 (FIG. 1 and the like). Further, the water spray type dry cooler 51 as a wet cooling means cools the air 3 using the latent heat of evaporation of water sprayed in a predetermined range before the heat transfer unit 511, so that the air cooling effect of the heat transfer unit 511 is achieved. In other words, the cooling effect of the circulating water is higher than that during dry operation.

The water spray type dry cooler 51 as the secondary cooling means 22D is:
(1) The blower as a dry cooling means is only off (stopped) water flow,
Spraying part (watering part) 513 as a wet cooling means is off (stop: no spraying),
(2) The blower as a dry cooling means is on (started),
Spraying part (watering part) 513 as a wet cooling means is off (stop: no spraying),
(3) The blower as a dry cooling means is on (start),
Spraying part (watering part) 513 as a wet cooling means is on (activation: spraying),
The cooling stage (operating state) is switched to these three stages.

FIG. 10 is a system schematic diagram (second diagram) schematically showing a cooling system 30 centering on a cooling facility of the fourth underground substation transformer cooling system 10D (in FIG. 10 , one bank is shown). Example).

  In the fourth underground substation transformer cooling system 10D, for example, as shown in FIG. 10, instead of the water spray type dry cooler 51 of the secondary cooling means 22D shown in FIG. A water spray type dry cooler 53 can also be provided.

  The water spray type dry cooler 53 includes a heat transfer unit 531 and a spray unit 533, and has a configuration similar to the water spray type dry cooler 51 including a heat transfer unit 511 and a spray unit 513. The spray destination is different from the watering type dry cooler 51. In the water spray type dry cooler 53, since it sprays from the spray part 533 to the heat transfer part 531, higher heat transfer performance than the water spray type dry cooler 51 can be obtained by the evaporation effect from the heat transfer surface. Therefore, the heat transfer area can be reduced, and the apparatus can be further downsized. In addition, the operation stage of the water spray type dry cooler 53 is a three-stage operation like the operation stage of the water spray type dry cooler 51.

  Subsequently, an underground substation transformer cooling method (hereinafter referred to as “fourth underground substation transformer cooling method”) using the fourth underground substation transformer cooling system 10D will be described.

  The fourth underground substation transformer cooling system 10D is a first underground substation transformer cooling system configured by separating dry cooling means (dry cooler 41) and wet cooling means (wet cooler 43). Unlike 10A, it is different in that the dry cooling means and the wet cooling means are configured to be integrated, that is, provided with watering type dry coolers 51 and 53 that can operate as a dry type or a wet type.

  However, since the concept of transformer cooling is the same in both the first underground substation transformer cooling system 10A and the fourth underground substation transformer cooling system 10D, most of the processing steps of the operation control procedure are the fourth. The underground substation transformer cooling system 10D is also executed in the same manner as the first underground substation transformer cooling system 10A.

  However, since the operation stage that can be switched by the water spray type dry coolers 51 and 53 is three stages, the processing content of the cooler recommended operation state determination step in the fourth underground substation transformer cooling method is, for example, the above-described figure. The contents are the same as those shown in FIG. In the present embodiment, the threshold value (set temperature) T2 is handled as a temperature at which the spray units 513 and 533 of the water spray type dry coolers 51 and 53 are turned on (with spraying: wet operation).

  According to the fourth underground substation transformer cooling system 10D and the fourth underground substation transformer cooling method, the first underground substation transformer cooling system 10A and the first underground substation transformer cooling system In addition to having the same effect as the underground substation transformer cooling method using 10A, the configuration of the secondary cooling means 22D can be further simplified. Moreover, since the water spray type dry coolers 51 and 53 in the secondary cooling means 22D do not generate water that requires sewage treatment, it is possible to obtain a greater effect of reducing water bills.

  Note that the above-described fourth underground substation transformer cooling system 10D is different from the first underground substation transformer cooling system 10A in place of the dry cooler 41 and the wet cooler 43 in the form of a water spray type dry cooler. 51 or a water spray type dry cooler 53, it can also be applied to the second underground substation transformer cooling system 10B. That is, instead of the dry cooler 41 and the wet cooler 43 in the second underground substation transformer cooling system 10B, a water spray type dry cooler 51 or a water spray type dry cooler 53 can be provided.

  As described above, according to the first to fourth underground substation transformer cooling systems 10A to 10D and the first to fourth underground substation transformer cooling methods, the wet operation time can be limited to a limited time throughout the year. (Depending on the outside air temperature and the transformer load, the operation time can be reduced to zero), so water can be saved significantly (up to 100%) compared to the conventional case. Therefore, it is possible to greatly reduce water bills (water supply bills and sewer bills) required when operating the first to fourth underground substation transformer cooling systems 10A to 10D.

  In addition, in the first to fourth underground substation transformer cooling systems 10A to 10D, even if a water outage occurs due to the occurrence of a large-scale disaster or the like, it is necessary to operate the secondary cooling means 22A to 22D. Since the water is almost zero, the cooling of the transformer 1 can be continued. That is, it is possible to provide a transformer cooling system and a transformer cooling method for an underground substation that is resistant to disaster.

  Furthermore, in the first to fourth underground substation transformer cooling systems 10A to 10D, the time required for wet operation is negligible throughout the year (zero depending on the year). Scale (scale) adhesion hardly occurs in the watering type dry coolers 51 and 53. In addition, since it is not necessary to operate in a wet manner over a long period of time (regularly), it is not necessary to take preventive measures for legionellosis, and it is possible to reduce the effort and cost required for the preventive measures for legionellosis.

  Furthermore, in the first to fourth underground substation transformer cooling systems 10A to 10D, the installation area of the secondary cooling means 22A to 22D can be reduced to about 2/3 or less compared to the conventional case. It can be made into a space. Therefore, in general, in the underground substations in urban areas where it is difficult to secure a large installation space as the cooling facilities tend to become large-scale, if the same installation space as the current situation can be secured, not only at the time of new installation but also at the time of renovation The first to fourth underground substation transformer cooling systems 10A to 10D can also be applied.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be implemented in various forms other than the above-described examples in the implementation stage, and within the scope not departing from the gist of the invention. Various omissions, additions, replacements, and changes can be made. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 Transformer (object to be cooled)
3 Air 10A to 10D Substation transformer cooling system 21 Primary cooling means 22A to 22D Secondary cooling means 30 Cooling system 31 Circulating water pump 32 Supply water tank 35 Thermometer 37 Spray water pump 38 Valve 41 Dry type cooler 411 Heat transfer Units 43 and 47 Wet cooler 431 Heat transfer unit 432 and 472 Water spray pump 433 and 473 Water spray unit 45 Heat exchanger 46a to 46d Valve 48 Heat exchanger 51 and 53 Water spray type dry cooler 511 and 531 Heat transfer unit 513 and 533 Spray section

Claims (11)

Primary cooling means provided on a path through which the circulating water circulates, and removing heat generated from the transformer installed in the underground substation by exchanging heat with the circulating water;
A secondary cooling unit that is installed on a path where the circulating water circulates at a position away from the primary cooling unit, and cools the hot water that is the circulating water after passing through the primary cooling unit;
The secondary cooling means passes between the dry cooling means and the primary cooling means, at least one dry cooling means that can be dry-operated by blowing air without using water for cooling at high temperature and high load. By using the water for cooling at the time of high temperature and high load that can exchange heat after the dry cooling means and before the primary cooling means, and using the air blown by a blower separate from the blower of the dry cooling means At least one wet cooling means capable of being wet-operated , wherein the dry cooling means and the wet cooling means are independently formed, and the dry cooling means is regularly cooled and operated, and the wet cooling means The substation transformer cooling system is configured to be preliminarily cooled in addition to the dry cooling means only when the cooling capacity is further increased . The dry cooling means is composed of at least one dry cooler having a blower ,
The substation transformer according to claim 1, wherein the wet cooling means includes at least one wet cooler having a blower separate from the watering pump and the blower of the dry cooler. Cooling system. A first heat exchanger for exchanging heat with the circulating water is further installed between the dry cooling means and the wet cooling means,
Passing the circulating water after passing the dry cooling means to the primary side of the first heat exchanger, allowing the circulating water after passing water to flow into the primary cooling means,
The underground substation according to claim 1 or 2, wherein water cooled by the wet cooling means is circulated through the secondary side of the first heat exchanger in a circulating manner. Transformer cooling system. The transformer cooling system for an underground substation according to claim 3, wherein the wet cooling means comprises an open type cooling tower. The secondary cooling means is configured to be able to switch on and off the dry operation by the dry cooling means and on and off the wet operation by the wet cooling means according to the temperature of the circulating water,
When the temperature of the circulating water rises to a first preset temperature, the dry operation is switched from off to on,
The wet operation is switched from off to on when the temperature of the circulating water rises to a preset second temperature that is higher than the first temperature. The transformer cooling system for an underground substation according to any one of the above. The secondary cooling means is configured to be able to switch on and off the dry operation by the dry cooling means and on and off the wet operation by the wet cooling means according to the temperature of the circulating water,
When the temperature of the circulating water drops to a preset third temperature, the wet operation is switched from on to off,
The dry operation is switched from on to off when the temperature of the circulating water drops to a preset fourth temperature lower than the third temperature. The transformer cooling system for an underground substation according to any one of the above. The secondary cooling means is configured to be able to switch on and off the dry operation by the dry cooling means and on and off the wet operation by the wet cooling means according to the temperature of the circulating water,
When the temperature of the circulating water rises to a first preset temperature, the dry operation is switched from off to on,
When the temperature of the circulating water rises to a preset second temperature that is higher than the first temperature, the wet operation is switched from off to on,
The wet operation is switched from on to off when the temperature of the circulating water drops to a preset third temperature that is lower than the second temperature;
The dry operation is switched from on to off when the temperature of the circulating water falls to a fourth temperature that is lower than the third temperature that is set in advance and lower than the first temperature. The transformer cooling system for an underground substation according to any one of claims 1 to 6, wherein The underground substation according to any one of claims 1 to 7 , further comprising a second heat exchanger for exchanging heat with the circulating water before the dry cooling means. Transformer cooling system. Wherein in parallel with at least one dry cooling means, according to any one of claims 1 to 7, characterized in that the second further established a heat exchanger for exchanging heat between the circulating water Transformer cooling system for underground substation. The design temperature of the dry cooling means and the wet cooling means is set on the basis of the outdoor temperature in the hottest midsummer year of the city where the underground substation is installed,
When the cooling capacity of the dry cooling means is lower than a set design temperature, the transformer can be operated at 100% load with the dry cooling means on and the wet cooling means off. Value is set to
The cooling capacity of the wet cooling means is set to a value that allows 100% load operation of the transformer when the dry cooling means is on and the wet cooling means is on at the set design temperature. The transformer cooling system for an underground substation according to any one of claims 1 to 9 , wherein the transformer cooling system is set. Primary cooling means provided on a path through which the circulating water circulates and removing heat generated from the transformer installed in the substation by exchanging heat with the circulating water, and the primary cooling means A secondary cooling unit that is installed on a path where the circulating water circulates at a distant position and cools the hot water that is the circulating water after passing through the primary cooling unit, and the secondary cooling unit includes: At least one dry cooling means that can be dry operated by blowing without using water for cooling at high temperature and high load, and the circulating water that passes between the dry cooling means and the primary cooling means, At least one capable of performing wet operation by blowing air from a blower separate from the blower of the dry cooling means and using water for cooling at a high temperature and high load after the dry cooling means and before the primary cooling means and capable of heat exchange Pieces And a wet cooling means, said formed by each independently of the dry cooling means and the wet cooling means, the dry cooling means are cooling operation customary manner, the wet cooling means only when further increasing the cooling capacity In addition to the dry cooling means, it is configured to be preliminarily cooled and operated, and is a transformer cooling method for an underground substation using a transformer cooling system for an underground substation,
Based on the measured temperature of the circulating water, it is determined whether the high temperature / high load or the normal operation is not the high temperature / high load, and the determination result is the normal operation Turning on the dry cooling means and turning off the wet cooling means;
When the determination result is at the time of the high temperature and high load, the step of turning on the dry cooling means and turning on the wet cooling means comprises: Transformer cooling of an underground substation Method.

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