CN114139401B - Overload capacity estimation method and device for oil immersed transformer - Google Patents
Overload capacity estimation method and device for oil immersed transformer Download PDFInfo
- Publication number
- CN114139401B CN114139401B CN202111499876.1A CN202111499876A CN114139401B CN 114139401 B CN114139401 B CN 114139401B CN 202111499876 A CN202111499876 A CN 202111499876A CN 114139401 B CN114139401 B CN 114139401B
- Authority
- CN
- China
- Prior art keywords
- temperature
- hot spot
- winding hot
- winding
- oil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Housings And Mounting Of Transformers (AREA)
- Protection Of Transformers (AREA)
Abstract
The application discloses an overload capacity estimation method and device of an oil immersed transformer, and particularly relates to a method and device for constructing a plurality of temperature calculation models; calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models; calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses; and calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value. Under the condition of obtaining sustainable operation time, operation and maintenance personnel can maintain or repair the oil immersed transformer according to the operation time, so that safe and stable operation of the power system is ensured.
Description
Technical Field
The present disclosure relates to the field of power equipment, and more particularly, to a method and apparatus for estimating overload capacity of an oil-immersed transformer.
Background
Along with the development of the Chinese power grid entering the stage of comprehensively implementing the strategy engineering of 'western electric east delivery, south-north interaction and national networking', the power system is developed towards the directions of large capacity, extra-high voltage and trans-regional, and the Chinese power grid is undoubtedly the most advanced and complex power grid in the world. The large power transmission and transformation equipment in the power system, particularly the power transformer, bears the task of voltage conversion in the system, is very important and expensive power equipment in the power system, and needs very long maintenance time once an accident occurs, so that serious influence is caused, and the safe and reliable operation of the power transmission and transformation equipment is directly related to the safety and stability of the whole power grid.
With the acceleration of power grid construction, the single capacity of the transformer is continuously increased, and the voltage level is also continuously improved. In general, the larger the capacity and the higher the voltage level of the transformer, the higher the failure rate and the larger the loss and the influence range due to the failure. Therefore, higher demands are placed on the safe operation and power supply reliability of the power system. The state monitoring of the power transformer is enhanced, the early latent fault of the power transformer can be timely and accurately judged, and treatment measures can be adopted early according to the monitoring result so as to ensure the safe and stable operation of the power system.
Disclosure of Invention
In view of this, the present application provides an overload capacity estimation method and device for an oil-immersed transformer, which are used for calculating a sustainable operation time of the oil-immersed transformer, so as to enable operation and maintenance personnel to maintain or repair the oil-immersed transformer according to the sustainable time, thereby ensuring safe and stable operation of an electric power system.
In order to achieve the above object, the following solutions have been proposed:
an overload capacity estimation method of an oil immersed transformer comprises the following steps:
constructing a plurality of temperature calculation models;
calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models;
calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses;
and calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value.
Optionally, the plurality of temperature calculation models includes a winding average temperature calculation model, a winding hot spot temperature calculation model, and an oil top layer temperature calculation model.
Optionally, the plurality of losses includes no-load losses, eddy current losses, and spurious losses.
Optionally, the step of calculating a temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses includes the steps of:
calculating the Wen Shengzhi under the overload condition according to an overload coefficient;
in the absence of the cooling device, the Wen Shengzhi is calculated from the proportion of the total cooling power of the actual cooling power station.
An overload capacity estimation device of an oil-immersed transformer, comprising:
the model construction module is used for constructing a plurality of temperature calculation models;
the loss calculation module is used for calculating various losses of the oil-immersed transformer according to the temperature calculation models;
the temperature rise calculation module is used for calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses;
and the estimation execution module is used for calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value.
Optionally, the plurality of temperature calculation models includes a winding average temperature calculation model, a winding hot spot temperature calculation model, and an oil top layer temperature calculation model.
Optionally, the plurality of losses includes no-load losses, eddy current losses, and spurious losses.
Optionally, the temperature rise calculation module includes:
a first calculation unit for calculating the Wen Shengzhi according to an overload coefficient in the overload condition;
and a second calculating unit, configured to calculate the Wen Shengzhi according to the proportion of the total cooling power of the actual cooling power station in the case that the cooling device is absent.
From the above technical solution, the application discloses a method and a device for estimating overload capacity of an oil immersed transformer, specifically, constructing a plurality of temperature calculation models; calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models; calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses; and calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value. Under the condition of obtaining sustainable operation time, operation and maintenance personnel can maintain or repair the oil immersed transformer according to the operation time, so that safe and stable operation of the power system is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of an overload capacity estimation method of an oil-immersed transformer according to an embodiment of the present application;
fig. 2 is a block diagram of an overload capacity estimation device of an oil-immersed transformer according to an embodiment of the present application;
fig. 3 is a block diagram of another overload capacity estimation device of an oil-immersed transformer according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
According to the characteristics of the load, such as size and duration, GBT1094.7 classifies the oil immersed transformer load into three categories, namely normal periodic load, long-term emergency load and short-term emergency load. The normal periodic load can be equivalent to the operation condition of the rated load in a certain period of time, so that the operation of the oil immersed transformer is not influenced, and the overload capacity of the oil immersed transformer is not required to be evaluated under the condition of the normal periodic load.
The long-term emergency load refers to long-term overload operation of the transformer caused by special conditions, the duration is long, the influence on the operation performance of the transformer is serious, and as the duration of the long-term emergency load is started by stopping operation of one transformer until the temperature of a hot spot caused by overload operation of the other transformers rises to a steady state, the overload capacity of the oil immersed transformer is only estimated from the perspective of Xu Guozai times for the load type.
Short-term emergency load refers to short-term overload operation of the transformer caused by special conditions, and the load is caused by temporary faults and has short duration, but hot spot temperature is easy to increase, so that the operation performance of the transformer is seriously influenced. The overload capability of the oil immersed transformer was evaluated from both Xu Guozai times and allowable overload time for short term emergency load types.
The allowable overload times can be calculated according to the overload times corresponding to the hot spot temperature and the steady state value of the oil top layer temperature reaching the allowable value. The accurate calculation of the winding hot spot temperature requires the use of the temperature of the inlet and outlet oil of the winding cooling gallery, taking into account the type of cooling medium, the cooling pattern, the winding gallery temperature rise, the correction of resistance and viscosity, and the changes in ambient temperature and load during a cycle.
The winding hot spot and the oil temperature are solved from the equation with energy stored at a small time interval Δt, and the system of this algorithm constitutes a transient forward finite difference method. The formula is applied by letting the temperature at the next time interval t1+Δt or t2 be calculated from the temperature solved for the initial time t1, this time being successively increased by Δt, the last calculated temperature being used to calculate the temperature at the next time point. At each point in time, the loss is calculated from the load and the loss is corrected by the resistance corrected for temperature variations. This algorithm also contains a correction for the fluid viscosity by temperature changes. In this way, the required accuracy will be achieved by selecting a small time increment Δt to calculate the hotspot temperature.
Based on the above requirements, the present application provides the following embodiments:
example 1
Fig. 1 is a flowchart of an overload capacity estimation method of an oil-immersed transformer according to an embodiment of the present application.
As shown in fig. 1, the overload capacity estimation method provided in this embodiment is used for calculating the sustainable operation time of the oil-immersed transformer, and specifically includes the following steps:
s1, constructing a plurality of temperature calculation models.
The plurality of temperature calculation models are related to the operation state and the operation parameters of the oil immersed transformer, and are respectively a winding average temperature calculation model, an oil duct and oil tank bottom temperature difference calculation model, a winding hot spot temperature calculation model, an oil average temperature calculation model, an oil top layer and oil tank bottom temperature difference calculation model, a viscosity calculation model and the like.
The winding average temperature calculation model is as follows:
the winding average temperature at the next moment:
Q GEN,W heat generated by winding W.min
Q LOST,W Heat dissipated by winding W.min
M W Cp w Heat capacity of winding, W.min/. Degree.C
θ W,1 Average winding temperature at initial time, DEG C
Heat generated by the windings:
k overload factor
P W DC resistance loss, W under rated condition
P E Eddy current loss at rated condition, W
K W Correction coefficient of average temperature of winding to resistance, value between 0.8 and 1
Δt is the time interval, min
Heat dissipated by the windings in ONAN, ONAF, and OFAF cooling modes:
θ W,1 average winding temperature at initial time, DEG C
θ W,R Average winding temperature in rated condition °c
θ DAO,1 Average oil duct temperature at initial time, DEG C
θ DAO,R Average temperature of oil duct under rated working condition (DEG C)
μ W,1 Viscosity, cP, at the initial moment corresponding to the average temperature of the winding
μ W,R Viscosity, cP, corresponding to the average temperature of the winding at nominal conditions
P W DC resistance loss, W under rated condition
P E Eddy current loss at rated condition, W
K 1， ，K 2 Distribution coefficient, K 1， A value of between 0.7 and 0.9, K 2 Is of a value between 0.1 and 0.2
Δt is the time interval, min
Heat dissipated by the windings in the ODAF cooling mode:
θ W,1 average winding temperature at initial time, DEG C
θ W,R Average winding temperature in rated condition °c
θ DAO，1 Average oil duct temperature at initial time, DEG C
θ DAO，R Average temperature of oil duct under rated working condition (DEG C)
P W DC resistance loss, W under rated condition
P E Eddy current loss at rated condition, W
Δt is the time interval, min
The calculation model of the temperature difference between the oil duct and the bottom of the oil tank is as follows:
θ BO temperature of the bottom of the oil tank at DEG C
Q LOST,W Heat dissipated by the windings
P W DC resistance loss, W under rated condition
P E Eddy current loss at rated condition, W
Δt is the time interval, min
θ TDO，R The top layer temperature of the oil duct is in DEG C under the rated working condition
θ BO，R Under rated working condition, the bottom temperature of the oil tank is in DEG C
K W Empirical coefficient of 0.88-1.05
The winding hot spot temperature calculation model is as follows:
hot spot temperature at next moment:
Q GEN,HS heat generated by winding hot spot temperature W.min
Q LOST,HS Heat dissipated by winding hot spot temperature W.min
M W Cp w Heat capacity of winding, W.min/. Degree.C
θ H，1 Winding hot spot temperature at initial moment, DEG C
Heat generated by hot spot temperature:
k overload factor
P HS Under rated working condition, the direct current resistance loss, W, of the winding at the hot spot temperature
K HS Correction coefficient of winding hot spot temperature to resistance, value between 0.75 and 1
P EHS Under rated working condition, eddy current loss, W, at winding hot spot temperature
Δt is the time interval, min
Heat dissipated by the windings in ONAN, ONAF, and OFAF cooling modes:
θ H，1 winding hot spot temperature at initial moment, DEG C
θ H,R Temperature of winding hot spot under rated working condition, DEG C
θ WO Temperature adjacent to winding hot spot temperature, DEG C
θ WO,R At a temperature adjacent to the rated operating mode and the winding hot spot temperature, DEG C
μ HS,l Viscosity, cP at the initial moment corresponding to the winding hot spot temperature
μ HS,R Viscosity, cP, corresponding to winding hot spot temperature at nominal operating conditions
P HS Under rated working condition, the direct current resistance loss, W, of the winding at the hot spot temperature
P EHS Under rated working condition, eddy current loss, W, at winding hot spot temperature
K 1， ，K 2 Distribution coefficient, K 1， A value of between 0.7 and 0.9, K 2 Is of a value between 0.1 and 0.2
Δt is the time interval, min
Heat dissipated by the windings in the ODAF cooling mode:
θ H，1 winding hot spot temperature at initial time，℃
θ H,R Temperature of winding hot spot under rated working condition, DEG C
θ WO Temperature adjacent to winding hot spot temperature, DEG C
θ WO,R At a temperature adjacent to the rated operating mode and the winding hot spot temperature, DEG C
P HS Under rated working condition, the direct current resistance loss, W, of the winding at the hot spot temperature
P EHS Under rated working condition, eddy current loss, W, at winding hot spot temperature
The oil average temperature calculation model is as follows:
oil average temperature at next moment:
Q LOST,W heat dissipated by winding W.min
Q S Heat generated by stray loss W.min
Q C Heat generated by no-load loss W.min
Q LOST,O Heat dissipated by transformer oil W.min
Total heat capacity of sigma MCp oil tank, iron core and transformer oil, W.min/. Degree.C
θ AO,1 Oil average temperature at initial time, DEG C
Heat generated by no-load loss:
Q C ＝P C，R Δt (11)
P C，R no-load loss, W
Δt is the time interval, min
Heat generated by stray losses:
k overload factor
P S Stray loss, W
K W Correction coefficient of average temperature of winding to resistance
Δt is the time interval, min
Heat dissipated by transformer oil:
θ AO，1 oil average temperature at initial time, DEG C
θ AO，R Average temperature of oil under rated conditions, DEG C
θ A，l Ambient temperature at initial time, C
θ A，R At ambient temperature, C, of the duty cycle
P T Total loss, W
Δt is the time interval, min
y index factor, ONAN:0.7 to 0.9; OFAF:0.75 to 0.95; ODAF:0.85 to 1
Total heat capacity of oil tank, core and transformer oil:
∑MCp＝M TANK Cp TANK +M CORE Cp CORE +M OIL Cp OIL (14)
M TANK weight of oil tank, kg
M CORE Weight of iron core, kg
M OIL Weight of transformer oil kg
Cp TANK Specific heat capacity of oil tank, W.min/kg DEG C
Cp CORE Specific heat capacity of iron core, W.min/kg DEG C
Cp OIL Specific heat capacity of transformer oil, W.min/kg DEG C
The temperature difference calculation model between the top oil layer and the bottom of the oil tank is as follows:
θ TO oil top layer temperature, DEG C
θ BO Temperature of the bottom of the oil tank, DEG C
Q LOST,O Heat dissipated by transformer oil W.min
P T Total loss, W
Δt is the time interval, min
θ TO,R Rated operating mode oil top layer temperature, DEG C
θ BO Temperature of bottom of oil tank under rated working condition, DEG C
K W Empirical coefficient of 0.88-1.05
Temperature of the bottom of the tank:
oil top layer temperature:
the viscosity calculation model is as follows:
μ＝De G /(θ+273) (18)
d mineral oil 0.0013573
G mineral oil 2797.3
A certain temperature for calculating the viscosity of the transformer oil at a certain temperature, a DEG C
S2, calculating various losses according to the temperature calculation model.
On the basis of the temperature calculation models, the various losses of the oil-immersed transformer are calculated, wherein the various losses are no-load losses, eddy current losses and stray losses, and the calculation method of the corresponding losses is described in detail in the steps and is not repeated here.
S3, calculating a temperature rise value by adopting a forward difference method and various losses.
The temperature rise value of the oil immersed transformer under the overload condition or the condition of the cooling equipment missing is obtained by calculating based on the multiple losses and based on a forward difference method.
Forward differencing: the accurate calculation of the temperature of the hot spot of the winding needs to use the oil temperature of the inlet and the outlet of the cooling oil duct of the winding, wherein the resistance value and the viscosity of the winding need to be corrected on the premise of considering the type of the cooling medium and the cooling mode, the resistance value changes along with the change of the temperature, the resistance loss changes along with the change of the viscosity along with the current temperature, and the change of the environment temperature and the load in one period needs to be considered, namely the input value.
The temperature of the winding hot spot and the oil are calculated with the energy stored in a small time interval, namely, the temperature of the next small time interval is calculated according to the temperature calculated in the initial time until the temperature at the moment when the calculation is needed. At each point in time, the loss is calculated from the load, and the loss is corrected by the resistance corrected for temperature changes, and the viscosity of the fluid is corrected by temperature changes. This algorithm is a forward differencing method, whose accuracy is such that the temperature calculation is achieved by selecting a small time increment.
When the oil-immersed transformer is under overload condition, calculation can be performed according to the overload coefficient and based on the above formulas (2), (7) and (13), so as to obtain corresponding temperature rise values.
In the event that the cooler portion of the oil immersed transformer is missing, the calculation of the actual cooling power is the key to the hot spot temperature and oil top layer temperature calculation method in this case. In the absence of a chiller, equation (13) will be deformed as:
this temperature rise value is thus obtained, where k1 is the ratio of the actual cooling power to the total cooling power.
And S4, calculating the sustainable operation time according to the load temperature rise limiting value and the temperature rise value.
The compliance temperature rise limit is determined here from GBT 1094.7. Relative aging rate of non-heat modified paper of oil immersed transformer:
wherein θ h Winding hot spot temperature, DEG C
Relative aging rate of thermally modified paper:
the equivalent aging coefficient consumed in a given time over a given temperature period is as follows:
the percent insulation life loss over a period of time is equal to the equivalent hours of life consumed divided by the total normal insulation life (h), multiplied by 100. The total time period typically used is 24 hours.
Since the running time under the optimal working condition is known when leaving the factory, the service life loss and the running time are subtracted, and the sustainable running time can be obtained.
As can be seen from the above technical solutions, the present embodiment provides an overload capacity estimation method for an oil-immersed transformer, specifically, a plurality of temperature calculation models are constructed; calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models; calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses; and calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value. Under the condition of obtaining sustainable operation time, operation and maintenance personnel can maintain or repair the oil immersed transformer according to the operation time, so that safe and stable operation of the power system is ensured.
Example two
Fig. 2 is a block diagram of an overload capacity estimation device of an oil-immersed transformer according to an embodiment of the present application.
As shown in fig. 2, the overload capacity estimation device provided in this embodiment is configured to operate a sustainable operation time of an oil-immersed transformer, and specifically includes a model building module 10, a loss calculating module 20, a temperature rise calculating module 30, and an estimation executing module 40.
The model construction module is used for constructing a plurality of temperature calculation models.
The plurality of temperature calculation models are related to the operation state and the operation parameters of the oil immersed transformer, and in this regard, a plurality of temperature calculation models, including a winding average temperature calculation model, an oil duct and oil tank bottom temperature difference calculation model, a winding hot spot temperature calculation model, an oil average temperature calculation model, an oil top layer and oil tank bottom temperature difference calculation model, a viscosity calculation model, and the like, can be constructed based on the model construction module. The above model has been described in detail in the previous embodiment, and will not be described here again.
The loss calculation module is used for calculating various losses according to the temperature calculation model.
That is, the module calculates multiple losses of the oil immersed transformer based on the multiple temperature calculation models, wherein the multiple losses are no-load loss, eddy current loss and stray loss respectively, and the calculation method of the corresponding losses is already described in detail in the above steps and is not repeated here.
The temperature rise calculation module is used for calculating a temperature rise value by adopting a forward difference method and various losses.
The temperature rise value of the oil immersed transformer under the overload condition or the condition of the cooling equipment missing is obtained by calculating based on the multiple losses and based on a forward difference method. The module comprises a first computing unit 31 and a second computing unit 32, as shown in fig. 3.
The first calculating unit is used for calculating according to the overload coefficient and based on the formulas (2), (7) and (13) when the oil immersed transformer is under the overload condition, so as to obtain corresponding temperature rise values.
In the event that the cooler portion of the oil immersed transformer is missing, the calculation of the actual cooling power is the key to the hot spot temperature and oil top layer temperature calculation method in this case. In the absence of a chiller, equation (13) will be deformed as:
the second calculation unit is configured to calculate the temperature rise value based on the above, where k1 is a ratio of the actual cooling power to the total cooling power.
The estimation execution module is used for calculating the sustainable operation time according to the load temperature rise limiting value and the temperature rise value.
The compliance temperature rise limit is determined here from GBT 1094.7. Relative aging rate of non-heat modified paper of oil immersed transformer:
wherein θ h Winding hot spot temperature, DEG C
Relative aging rate of thermally modified paper:
the equivalent aging coefficient consumed in a given time over a given temperature period is as follows:
the percent insulation life loss over a period of time is equal to the equivalent hours of life consumed divided by the total normal insulation life (h), multiplied by 100. The total time period typically used is 24 hours.
Since the running time under the optimal working condition is known when leaving the factory, the service life loss and the running time are subtracted, and the sustainable running time can be obtained.
As can be seen from the above technical solutions, the present embodiment provides an overload capacity estimation device for an oil immersed transformer, which is specifically configured to construct a plurality of temperature calculation models; calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models; calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses; and calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value. Under the condition of obtaining sustainable operation time, operation and maintenance personnel can maintain or repair the oil immersed transformer according to the operation time, so that safe and stable operation of the power system is ensured.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by differences from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It will be apparent to those skilled in the art that embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the invention may take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the invention.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.
The foregoing has outlined rather broadly the more detailed description of the invention in order that the detailed description of the invention that follows may be better understood, and in order that the present principles and embodiments may be better understood; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (8)
1. The overload capacity estimation method of the oil immersed transformer is characterized by comprising the following steps of:
constructing a plurality of temperature calculation models;
calculating multiple losses of the oil-immersed transformer according to the multiple temperature calculation models;
calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses;
calculating sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value;
the temperature calculation model comprises a winding hot spot temperature calculation model, and the winding hot spot temperature calculation model is as follows:
hot spot temperature at next moment:
wherein Q is GEN，HS Heat generated for winding hot spot temperature;
Q LOST，HS heat dissipated for winding hot spot temperature;
M W Cp w is the heat capacity of the winding;
θ H，1 the winding hot spot temperature at the initial moment;
heat generated by hot spot temperature:
k is an overload coefficient;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
K HS the correction coefficient of the winding hot spot temperature to the resistance is used;
P EHS the eddy current loss is the eddy current loss at the temperature of a winding hot spot under the rated working condition;
Δt is the time interval;
heat dissipated by the windings in ONAN, ONAF, and OFAF cooling modes:
θ H，1 the winding hot spot temperature at the initial moment;
θ H，R the temperature of the winding hot spot is the rated working condition;
θ WO is a temperature adjacent to the winding hot spot temperature;
θ WO，R is a temperature adjacent to the winding hot spot temperature at rated operating conditions;
μ HS，1 the viscosity corresponding to the temperature of the winding hot spot at the initial moment;
μ HS，R corresponding to winding hot spot under rated working conditionViscosity at temperature;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
P EHS the eddy current loss is the eddy current loss at the temperature of a winding hot spot under the rated working condition;
K 1， ，K 2 for the distribution coefficient;
Δt is the time interval;
heat dissipated by the windings in the ODAF cooling mode:
θ H，1 the winding hot spot temperature at the initial moment;
θ H，R the temperature of the winding hot spot is the rated working condition;
θ WO is a temperature adjacent to the winding hot spot temperature;
θ WO，R is a temperature adjacent to the winding hot spot temperature at rated operating conditions;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
P EHS for eddy current losses at the winding hot spot temperature under nominal conditions.
2. The overload capability estimation method of claim 1, wherein the plurality of temperature calculation models includes a winding average temperature calculation model, a winding hot spot temperature calculation model, and an oil top layer temperature calculation model.
3. The overload capability estimation method of claim 1, wherein the plurality of losses includes no-load loss, eddy current loss, and spurious loss.
4. The overload capacity estimation method according to claim 1, wherein the calculation of the temperature rise value of the oil immersed transformer in the case of overload or the absence of cooling equipment using the forward difference method and the plurality of losses includes the steps of:
calculating the Wen Shengzhi under the overload condition according to an overload coefficient;
in the absence of the cooling device, the Wen Shengzhi is calculated from the actual cooling power to total cooling power ratio.
5. An overload capacity estimation device for an oil-immersed transformer, comprising:
the model construction module is used for constructing a plurality of temperature calculation models;
the loss calculation module is used for calculating various losses of the oil-immersed transformer according to the temperature calculation models;
the temperature rise calculation module is used for calculating the temperature rise value of the oil immersed transformer under the overload condition or the cooling equipment missing condition by adopting a forward difference method and the multiple losses;
the estimation execution module is used for calculating the sustainable operation time of the oil immersed transformer according to a preset load temperature rise limit value and the temperature rise value;
the temperature calculation model comprises a winding hot spot temperature calculation model, and the winding hot spot temperature calculation model is as follows:
hot spot temperature at next moment:
wherein Q is GEN，HS Heat generated for winding hot spot temperature;
Q LOST，HS heat dissipated for winding hot spot temperature;
M W Cp w is the heat capacity of the winding;
θ H，1 the winding hot spot temperature at the initial moment;
heat generated by hot spot temperature:
k is an overload coefficient;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
K HS the correction coefficient of the winding hot spot temperature to the resistance is used;
P EHS the eddy current loss is the eddy current loss at the temperature of a winding hot spot under the rated working condition;
Δt is the time interval;
heat dissipated by the windings in ONAN, ONAF, and OFAF cooling modes:
θ H，1 the winding hot spot temperature at the initial moment;
θ H，R the temperature of the winding hot spot is the rated working condition;
θ WO is a temperature adjacent to the winding hot spot temperature;
θ WO，R is a temperature adjacent to the winding hot spot temperature at rated operating conditions;
μ HS，1 the viscosity corresponding to the temperature of the winding hot spot at the initial moment;
μ HS，R viscosity corresponding to the temperature of the winding hot spot under rated working conditions;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
P EHS the eddy current loss is the eddy current loss at the temperature of a winding hot spot under the rated working condition;
K 1 ，K 2 for the distribution coefficient;
Δt is the time interval;
heat dissipated by the windings in the ODAF cooling mode:
θ H，1 the winding hot spot temperature at the initial moment;
θ H，R the temperature of the winding hot spot is the rated working condition;
θ WO is a temperature adjacent to the winding hot spot temperature;
θ WO，R is a temperature adjacent to the winding hot spot temperature at rated operating conditions;
P HS the direct current resistance loss is the direct current resistance loss at the temperature of the winding hot spot under the rated working condition;
P EHS for eddy current losses at the winding hot spot temperature under nominal conditions.
6. The overload capability estimation apparatus of claim 5, wherein the plurality of temperature calculation models includes a winding average temperature calculation model, a winding hot spot temperature calculation model, and an oil top layer temperature calculation model.
7. The overload capability estimation apparatus of claim 5 wherein the plurality of losses include no-load losses, eddy current losses, and spurious losses.
8. The overload capacity estimation device of claim 5, wherein the temperature rise calculation module includes:
a first calculation unit for calculating the Wen Shengzhi according to an overload coefficient in the overload condition;
and the second calculating unit is used for calculating Wen Shengzhi according to the proportion of the actual cooling power to the total cooling power in the absence of the cooling equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111499876.1A CN114139401B (en) | 2021-12-09 | 2021-12-09 | Overload capacity estimation method and device for oil immersed transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111499876.1A CN114139401B (en) | 2021-12-09 | 2021-12-09 | Overload capacity estimation method and device for oil immersed transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114139401A CN114139401A (en) | 2022-03-04 |
| CN114139401B true CN114139401B (en) | 2023-08-08 |
Family
ID=80385379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111499876.1A Active CN114139401B (en) | 2021-12-09 | 2021-12-09 | Overload capacity estimation method and device for oil immersed transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114139401B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103543352A (en) * | 2013-09-25 | 2014-01-29 | 国家电网公司 | Method for determining dynamic overload curves of transformers based on operating data |
| CN107843791A (en) * | 2017-11-06 | 2018-03-27 | 西安交通大学 | A kind of transformer load capability assessment method based on temperature characteristic |
| CN111564288A (en) * | 2020-05-25 | 2020-08-21 | 云南电网有限责任公司电力科学研究院 | Cooling device for overload of oil immersed transformer and control method thereof |
-
2021
- 2021-12-09 CN CN202111499876.1A patent/CN114139401B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103543352A (en) * | 2013-09-25 | 2014-01-29 | 国家电网公司 | Method for determining dynamic overload curves of transformers based on operating data |
| CN107843791A (en) * | 2017-11-06 | 2018-03-27 | 西安交通大学 | A kind of transformer load capability assessment method based on temperature characteristic |
| CN111564288A (en) * | 2020-05-25 | 2020-08-21 | 云南电网有限责任公司电力科学研究院 | Cooling device for overload of oil immersed transformer and control method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114139401A (en) | 2022-03-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6569014B2 (en) | Online evaluation method for safety margin of power system operating reserve | |
| US9450409B2 (en) | Converter station power set point analysis system and method | |
| CN110120686B (en) | New energy bearing capacity early warning method based on online inertia estimation of power system | |
| CN105207247B (en) | Control method of electric power system and device | |
| CN109462225B (en) | Insulation matching method and system for series compensation device | |
| CN109066726B (en) | Frequency safety emergency coordination optimization control method integrating multiple measures | |
| Wouters et al. | Remaining lifetime modeling of power transformers: individual assets and fleets | |
| Nogay | Prediction of internal temperature in stator winding of three‐phase induction motors with ann | |
| CN110994589B (en) | Online evaluation method and system for frequency modulation capability of power electronic access power system | |
| Awadallah et al. | Probabilistic indicators for assessing age-and loading-based criticality of transformers to cascading failure events | |
| CN114417574B (en) | Method and device for calculating severity of turn-to-turn short circuit | |
| CN114139401B (en) | Overload capacity estimation method and device for oil immersed transformer | |
| CN113837589B (en) | N-1 scheduling method and device for comprehensive energy system | |
| US20220291649A1 (en) | Method for computer-implemented determination of control parameters of a turbine | |
| Steinkohl et al. | Frequency security constrained control of power electronic‐based generation systems | |
| Jalal | Case study: Implementation of dynamic rating for transformers in a distribution network | |
| Lai et al. | Prediction of top oil temperature for oil-immersed transformer based on Kalman filter algorithm | |
| CN116054131A (en) | System minimum inertia estimation method based on general system frequency response model | |
| Zarei | Analysis of reliability improvements of transformers after application of dynamic rating | |
| JP6620445B2 (en) | Intake and discharge water temperature difference management method and intake and discharge water temperature difference management equipment | |
| Hassan et al. | Under-Frequency Load Shedding: Towards a smarter smart house with a consumer level controller | |
| Bajracharya et al. | Optimization of maintenance for power system equipment using a predictive health model | |
| Yan et al. | A thermal model based dynamic rating system for overhead transmission lines | |
| Fan et al. | Steady frequency prediction algorithm for power system with governor deadband | |
| Alizadeh et al. | Multiobjective optimal setting for UFLS relays considering voltage deviation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |