CN109672225B - Automatic control strategy for adjusting and eliminating overload of 220kV transformer - Google Patents

Abstract

The invention relates to an automatic control strategy for adjusting and eliminating 220kV transformer overload, which comprises the following steps: in the transformer T_iWhen the load is overloaded by delta L, the loads of loads 1,2, 3 and 4 of the main switches QF1, QF2, QF3 and QF4 at low voltage are transferred to another transformer T through the middle-low voltage side adjustment_jAnd at this time the transformer T_jLoads load1 and load2 of main switches QF1 and QF2 with capacity margin M of low voltage are transferred to transformer T through medium and low voltage side adjustment_jAnd at this time the transformer T_jCapacity margin of M₁(ii) a Loads load3 and load4 of low-voltage main switches QF3 and QF4 are transferred to the transformer T through medium-low voltage side adjustment_nAnd then T is present_nCapacity margin of M₂. The invention has reasonable design, fully considers the possible load transfer condition which can occur when the 220kV transformer is overloaded in actual operation, and can automatically, quickly and quantitatively generate the strategy information for eliminating the transferred load of the medium and low voltage sides of the overloaded 220kV transformer.

Description

Automatic control strategy for adjusting and eliminating overload of 220kV transformer

Technical Field

The invention belongs to the technical field of transformers, and particularly relates to an automatic control strategy for adjusting and eliminating overload of a 220kV transformer.

Background

When the 220kV transformer is overloaded, a dispatcher should take relevant operations in time, and eliminate the equipment overload by adjusting the middle and low voltage sides of the transformer, otherwise, the transformer is damaged, and the accident influence is enlarged.

At present, a dispatcher generally carries out manual ordering operation according to operation experience, the automation and intelligence level of the mode is low, and no related system or application can automatically provide a mode adjustment strategy in the aspect, so that an automatic assistant decision-making method for quickly eliminating transformer overload is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides an automatic control strategy for adjusting and eliminating the overload of a 220kV transformer, can reduce or eliminate the damage to equipment caused by the overload, improves the automation and intelligence level of work of dispatching personnel, and further improves the capability of controlling the operation of a power grid.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

an automatic control strategy for adjusting and eliminating overload of a 220kV transformer comprises the following steps:

step 1, in transformer T_iWhen the load is overloaded by delta L, the loads of loads 1,2, 3 and 4 of the main switches QF1, QF2, QF3 and QF4 at low voltage are transferred to another transformer T through the middle-low voltage side adjustment_jAnd at this time the transformer T_jThe capacity margin is M;

step 2, low pressure receivingLoads load1 and load2 of the main switches QF1 and QF2 are transferred to the transformer T through medium-low voltage side adjustment_jAnd at this time the transformer T_jCapacity margin of M₁(ii) a Loads load3 and load4 of low-voltage main switches QF3 and QF4 are transferred to the transformer T through medium-low voltage side adjustment_nAnd then T is present_nCapacity margin of M₂。

Further, the specific implementation method of step 1 includes the following steps:

firstly, setting: load is greater than or equal to 0 and less than or equal to 1 and less than or equal to load is greater than or equal to 2 and less than or equal to load is equal to 3 and less than or equal to 4, and the secondary transformer T is calculated_iSide transfer of load to T at medium and low pressure_jAll possible values of (a): load1, load2, load3, load4, load1+ load2, load1+ load3, load1+ load4, load2+ load3, load2+ load4, load3+ load4, load1+ load2+ load3, load1+ load2+ load4, load1+ load3+ load4, load2+ load3+ load4 and load1+ load2+ load3+ load4, wherein the 15 values respectively correspond to a low-pressure side-shifting load mode; the 15 values are sorted from small to large as follows: l is more than or equal to 0₁≤L₂≤L₃≤…≤L₁₄≤L₁₅And further form a 16-value interval of [ L ]₀,L₁),[L₁,L₂)…[L₁₄,L₁₅),[L₁₅,L₁₆) Wherein L is₀＝0、L₁₆＝∞；

Secondly, according to the calculation result of the steps, if M is located in [ L ]₀,L₁) Interval of values, transformer T_jThe capacity margin M of the system can not meet any load shedding mode;

performing the calculation result of the first step, if M is located at [ L ]_i,L_i+1) Value interval, i ∈ 1,2 … 15, further consider [ L₀,L₁),[L₁,L₂)…[L_i-1,L_i) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ L ]_k,L_k+1) The value interval, k ∈ 0,1,2 … i-1, is then expressed as L_k+1Adjusting the in-station mode by the corresponding load transfer method, and starting a load flow calculation module for verification; if delta L is larger than or equal to L_iThen press L_iCorresponding load transfer method for adjusting in-station sideAnd starting a load flow calculation module for verification.

Further, the power flow calculation is calculation for determining steady-state operation state parameters of all parts of the power system according to a given power grid structure and parameters and operation conditions of a generator and a load element; the operating conditions include power at each power and load point in the system, junction point voltage, voltage at the balance point, and phase angle.

Further, the specific implementation method of step 2 includes the following steps:

firstly, setting: load is greater than or equal to 0 and less than or equal to 1 and less than or equal to 2, load is greater than or equal to 0 and less than or equal to 3 and less than or equal to 4, and the secondary transformer T is calculated_iTransferring load to transformer T from medium and low voltage side_jFirst set of 3 values: load1, load2, load1+ load2, the first group of 3 values respectively corresponding to a slave T_iSide transfer of load to T at medium and low pressure_jThe manner of (a); recalculate the slave T_iSide transfer of load to T at medium and low pressure_nSecond set of 3 values: load3, load4, load3+ load4, the second group of 3 values respectively corresponding to a slave T_iSide transfer of load to T at medium and low pressure_nThe manner of (a); the two groups of numerical values are respectively sorted from small to big: l is more than or equal to 0₁≤L₂≤L₃，0≤H₁≤H₂≤H₃The two groups are respectively formed into 3 numerical intervals: [ L ]₀,L₁),[L₁,L₂),[L₂,L₃),[L₃,L₄)；[H₀,H₁),[H₁,H₂),[H₂,H₃),[H₃,H₄) Wherein L is₀＝H₀＝0、L₄＝H₄Infinity; creating an empty set S₁{}、S₂{}、S₃{}；

The calculation result of the method is shown in the following steps: if M₁Is located in [ L₀,L₁) Interval of values, T_jCapacity margin M of₁Any load shedding mode cannot be met; if M₁Is located in [ L_i,L_i+1) Value interval, i ∈ (1,2 … 3), and L₁,…L_iWrite set S₁Is S₁{L₁,…L_i}；

The calculation result of the method is shown in the step: if M₂Is located in [ H ]₀,H₁) Interval of values, T_nCapacity margin M of₂Any load shedding mode cannot be met; if M₂Is located in [ H ]_k,H_k+1) Value interval, k ∈ (1,2 … 3), H₁,…H_kWrite set S₂Is S₂{H₁,…H_k}；

Step S is achieved according to the calculation results of the step two and the step three₁And S₂Element writing S of a set₃And then S is₁Any one of the elements with S₂The sum of any of the elements is also written into S₃The method comprises the following steps: if S₃The collection is still empty, which indicates that no real feasible mode for transferring the load at the middle and low pressure side exists in the station; if S₃Now a non-empty set S₃{G₁,,…G_fForm of (i), where f e (i, k, i + k + i) k), set S₃Each element in (1) corresponds to a slave T_iMedium and low pressure side load transfer to T_j、T_nA combination of the process of (1) and (B)₃All elements in the formula are sorted from small to large, and G is more than or equal to 0₁≤G₂≤…≤G_fFurther, f number value intervals are formed, [ G ]₀,G₁),[G₁,G₂)…[G_f-1,G_f) Wherein G is₀＝0；

Fifth, according to the calculation result of step four, consider [ G ]₀,G₁),[G₁,G₂)…[G_f-1,G_f) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ G ]_p,G_p+1) Value interval, k ∈ (0,1,2 … f-1), as G_p+1Adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification; if DeltaL is greater than or equal to G_fPress a G_fAnd adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification.

The invention has the advantages and positive effects that:

1. the invention eliminates the transformer overload through the middle and low voltage side adjustment of the 220kV transformer, takes the universal connection mode of the 220kV transformer as a model, is suitable for various common 220kV transformer connection modes, comprehensively considers the possible load transfer condition possibly occurring when the 220kV transformer is overloaded in actual operation, and can automatically, quickly and quantitatively generate the strategy information for eliminating the middle and low voltage side transfer load of the 220kV transformer overload.

2. The invention establishes the analysis model based on the universal 220kV transformer wiring form, so the applicability is very wide, and various overload faults of the 220kV transformer can be analyzed and processed.

3. According to the method, the capacity margin of the relevant transformer is considered when the strategy is adjusted based on the real-time topology generation mode in the station, the transferred load is quantized, and the correctness and the feasibility of the auxiliary strategy are ensured.

Drawings

Fig. 1 is a general wiring schematic diagram of a 220kV transformer.

Detailed Description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention considers the transformer T_iIn case of Δ L overload, the low voltage is loaded by the loads of the main switches QF1, QF2, QF3 and QF4, respectively load1, load2, load3 and load4, as shown in fig. 1, if the transformer T is overloaded, the load is equal to Δ L, and the load is equal to Δ L, or less than Δ L, or equal to Δ L, or less than Δ L, and the loads of the main switches QF, i, and the loads of the main switches QF, i, and the loads of the main switches QF, i, and the main switches QF, i, respectively, i, of the loads of the main switches QF1, and the loads of the main switches QF, and the loads of the main switches QF 8925, respectively load1, and the loads of the main switches QF, and the main switches QF, respectively load2, and the loads of the main switches QF, and the main switches QF, respectively, and the main switches QF, respectively load2, and the main switches QF_iAnd taking the corresponding load as 0 for processing without the corresponding switch. To eliminate T_iOverload, preparing to adopt a bus-tie or section switch with a hot standby state at the middle-low voltage side, and pulling T open_iAnd adjusting the strategy according to the load shedding mode of the master switch. Through in-station topology identification, when T_iWhen the load on a certain side cannot be adjusted to any other transformer in the station through the middle-low voltage side adjustment, the corresponding load is set to be 0 for processing. The treatment is divided into the following two cases;

1. the loads of load1, load2, load3 and load4 can be transferred to another transformer T by the medium-low voltage side adjustment_jAnd then T is present_jThe capacity margin is M. Without loss of generality, 0 ≦ load1 ≦ load2 ≦ load3 ≦ load 4.

(1) Calculate from T_iSide transfer of load to T at medium and low pressure_jAll ofPossible values are: load1, load2, load3, load4, load1+ load2, load1+ load3, load1+ load4, load2+ load3, load2+ load4, load3+ load4, load1+ load2+ load3, load1+ load2+ load4, load1+ load3+ load4, load2+ load3+ load4, load1+ load2+ load3+ load4, wherein the 15 values respectively correspond to a mode of middle-low pressure side shifting load. The 15 values are ordered from small to large and written as: l is more than or equal to 0₁≤L₂≤L₃≤…≤L₁₄≤L₁₅(wherein L_iRespectively corresponding to one of 15 numerical values), thereby forming a 16-numerical value interval of [ L ]₀,L₁),[L₁,L₂)…[L₁₄,L₁₅),[L₁₅,L₁₆) Wherein L is₀＝0、L₁₆＝∞。

(2) According to the calculation result of the step (1), if M is located at [ L ]₀,L₁) Interval of values, T_jThe capacity margin M of the system can not meet any load shedding mode;

(3) according to the calculation result of the step (1), if M is located at [ L ]_i,L_i+1) Value interval, i ∈ (1,2 … 15), further consider [ L ∈ L₀,L₁),[L₁,L₂)…[L_i-1,L_i) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ L ]_k,L_k+1) Value interval, k ∈ (0,1,2 … i-1), as L_k+1Adjusting the in-station mode by the corresponding load transfer method, and starting a load flow calculation module for verification; if delta L is larger than or equal to L_iPress L against_iAnd adjusting the in-station mode by using the corresponding load transfer method, and starting a load flow calculation module for verification.

The load flow calculation module is a common module in the power grid dispatching system. The tidal current calculation is a calculation for determining steady-state operation state parameters of each part of the power system according to the given power grid structure, parameters and operation conditions of elements such as a generator and a load. Typically given operating conditions there are power at each source and load point in the system, junction point voltage, voltage and phase angle at the balance point, etc.

2. Loads 1 and 2 can be transferred to the transformer T through medium-low voltage side adjustment_jAnd then T is present_jCapacity margin of M₁(ii) a Loads 3 and 4 are transferred to transformer T by medium-low voltage side regulation_nAnd then T is present_nCapacity margin of M₂. Without loss of generality, load is 1 and 2 are 0 and 3 and 4 are 0 and 3.

(1) Calculate from T_iSide transfer of load to T at medium and low pressure_jAll possible values of (a) are: load1, load2, load1+ load2, the 3 values of the first group corresponding to a respective one of the variables from T_iSide transfer of load to T at medium and low pressure_jThe manner of (a); recalculate the slave T_iSide transfer of load to T at medium and low pressure_nAll possible values of (a) are: load3, load4, load3+ load4, the 3 values of the second group corresponding to a respective one of the variables from T_iSide transfer of load to T at medium and low pressure_nThe method (1). The two groups of numerical values are respectively ordered from small to big and written as: l is more than or equal to 0₁≤L₂≤L₃(wherein L_iRespectively corresponding to one of the first group of values), 0 is less than or equal to H₁≤H₂≤H₃(wherein H is_iRespectively corresponding to one of the second set of values). The two groups can respectively form 3 value intervals [ L₀,L₁),[L₁,L₂),[L₂,L₃),[L₃,L₄)；[H₀,H₁),[H₁,H₂),[H₂,H₃),[H₃,H₄) Wherein L is₀＝H₀＝0、L₄＝H₄Infinity. In addition, an empty set S is created₁{}、S₂{}、S₃{}。

(2) According to the calculation result of the step (1): if M₁Is located in [ L₀,L₁) Interval of values, T_jCapacity margin M of₁Any load shedding mode cannot be met; if M₁Is located in [ L_i,L_i+1) Value interval, i ∈ (1,2 … 3), and L₁,…L_iWrite set S₁Is S₁{L₁,…L_i}。

(3) According to the calculation result of the step (1): if M₂Is located in [ H ]₀,H₁) Interval of values, T_nCapacity margin M of₂Any load shedding mode cannot be met; if M₂Is located in [ H ]_k,H_k+1) Value interval, k ∈ (1,2 … 3), H₁,…H_kWrite set S₂Is S₂{H₁,…H_k}。

(4) According to the calculation results of the steps (2) and (3), converting S₁And S₂Element writing S of a set₃And then S is₁Any one of the elements with S₂The sum of any of the elements is also written into S₃The method comprises the following steps: if S₃The collection is still empty, which indicates that no real feasible mode for transferring the load at the middle and low pressure side exists in the station; if S₃Now a non-empty set S₃{G₁,,…G_fForm of (i), where f e (i, k, i + k + i) k), set S₃Each element in (1) corresponds to a slave T_iMedium and low pressure side load transfer to T_j、T_nA combination of the process of (1) and (B)₃All elements in the formula are sorted from small to large, which is not a general assumption, and G is more than or equal to 0₁≤G₂≤…≤G_fFurther, f number value intervals are formed, [ G ]₀,G₁),[G₁,G₂)…[G_f-1,G_f) Wherein G is₀＝0。

(5) Based on the calculation result of step (4), [ G ] is examined₀,G₁),[G₁,G₂)…[G_f-1,G_f) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ G ]_p,G_p+1) Value interval, k ∈ (0,1,2 … f-1), as G_p+1Adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification; if DeltaL is greater than or equal to G_fPress a G_fAnd adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification.

It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.

Claims (3)

1. An automatic control strategy for adjusting and eliminating overload of a 220kV transformer is characterized in that: the method comprises the following steps:

step 1, in transformer T_iWhen the load is overloaded by delta L, the loads of loads 1,2, 3 and 4 of the main switches QF1, QF2, QF3 and QF4 at low voltage are transferred to another transformer T through the middle-low voltage side adjustment_jAnd at this time the transformer T_jThe capacity margin is M;

step 2, transferring loads load1 and load2 of low-voltage slave master switches QF1 and QF2 to the transformer T through medium-low voltage side adjustment_jAnd at this time the transformer T_jCapacity margin of M₁(ii) a Loads load3 and load4 of low-voltage main switches QF3 and QF4 are transferred to the transformer T through medium-low voltage side adjustment_nAnd then T is present_nCapacity margin of M₂；

The specific implementation method of the step 1 comprises the following steps:

firstly, setting: load is greater than or equal to 0 and less than or equal to 1 and less than or equal to load is greater than or equal to 2 and less than or equal to load is equal to 3 and less than or equal to 4, and the secondary transformer T is calculated_iSide transfer of load to T at medium and low pressure_jAll possible values of (a): load1, load2, load3, load4, load1+ load2, load1+ load3, load1+ load4, load2+ load3, load2+ load4, load3+ load4, load1+ load2+ load3, load1+ load2+ load4, load1+ load3+ load4, load2+ load3+ load4 and load1+ load2+ load3+ load4, wherein the 15 values respectively correspond to a low-pressure side-shifting load mode; the 15 values are sorted from small to large as follows: l is more than or equal to 0₁≤L₂≤L₃≤…≤L₁₄≤L₁₅And further form a 16-value interval of [ L ]₀,L₁),[L₁,L₂)…[L₁₄,L₁₅),[L₁₅,L₁₆) Wherein L is₀＝0、L₁₆＝∞；

Secondly, according to the calculation result of the steps, if M is located in [ L ]₀,L₁) Interval of values, transformer T_jThe capacity margin M of (A) cannot satisfy any inverse load sideFormula (I);

performing the calculation result of the first step, if M is located at [ L ]_i,L_i+1) Value interval, i ∈ 1,2 … 15, further consider [ L₀,L₁),[L₁,L₂)…[L_i-1,L_i) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ L ]_k,L_k+1) The value interval, k ∈ 0,1,2 … i-1, is then expressed as L_k+1Adjusting the in-station mode by the corresponding load transfer method, and starting a load flow calculation module for verification; if delta L is larger than or equal to L_iThen press L_iAnd adjusting the in-station mode by using the corresponding load transfer method, and starting a load flow calculation module for verification.

2. The automatic control strategy for regulating and eliminating the overload of the 220kV transformer according to claim 1, wherein: the tidal current calculation is to determine the calculation of steady-state operation state parameters of each part of the power system according to the given power grid structure and parameters and the operation conditions of the generator and the load element; the operating conditions include power at each power and load point in the system, junction point voltage, voltage at the balance point, and phase angle.

3. The automatic control strategy for regulating and eliminating the overload of the 220kV transformer according to claim 1, wherein: the specific implementation method of the step 2 comprises the following steps:

firstly, setting: load is greater than or equal to 0 and less than or equal to 1 and less than or equal to 2, load is greater than or equal to 0 and less than or equal to 3 and less than or equal to 4, and the secondary transformer T is calculated_iTransferring load to transformer T from medium and low voltage side_jFirst set of 3 values: load1, load2, load1+ load2, the first group of 3 values respectively corresponding to a slave T_iSide transfer of load to T at medium and low pressure_jThe manner of (a); recalculate the slave T_iSide transfer of load to T at medium and low pressure_nSecond set of 3 values: load3, load4, load3+ load4, the second group of 3 values respectively corresponding to a slave T_iSide transfer of load to T at medium and low pressure_nThe manner of (a); the two groups of numerical values are respectively sorted from small to big: l is more than or equal to 0₁≤L₂≤L₃，0≤H₁≤H₂≤H₃The two groups are respectively formed into 3 numerical intervals: [ L ]₀,L₁),[L₁,L₂),[L₂,L₃),[L₃,L₄)；[H₀,H₁),[H₁,H₂),[H₂,H₃),[H₃,H₄) Wherein L is₀＝H₀＝0、L₄＝H₄Infinity; creating an empty set S₁{}、S₂{}、S₃{}；

The calculation result of the method is shown in the following steps: if M₁Is located in [ L₀,L₁) Interval of values, T_jCapacity margin M of₁Any load shedding mode cannot be met; if M₁Is located in [ L_i,L_i+1) Value interval, i ∈ (1,2 … 3), and L₁,…L_iWrite set S₁Is S₁{L₁,…L_i}；

The calculation result of the method is shown in the step: if M₂Is located in [ H ]₀,H₁) Interval of values, T_nCapacity margin M of₂Any load shedding mode cannot be met; if M₂Is located in [ H ]_k,H_k+1) Value interval, k ∈ (1,2 … 3), H₁,…H_kWrite set S₂Is S₂{H₁,…H_k}；

Step S is achieved according to the calculation results of the step two and the step three₁And S₂Element writing S of a set₃And then S is₁Any one of the elements with S₂The sum of any of the elements is also written into S₃The method comprises the following steps: if S₃The collection is still empty, which indicates that no real feasible mode for transferring the load at the middle and low pressure side exists in the station; if S₃Now a non-empty set S₃{G₁,,…G_fForm of (i), where f e (i, k, i + k + i) k), set S₃Each element in (1) corresponds to a slave T_iMedium and low pressure side load transfer to T_j、T_nA combination of the process of (1) and (B)₃All elements in the formula are sorted from small to large, and G is more than or equal to 0₁≤G₂≤…≤G_fAnd then formForming an f number value interval, [ G ]₀,G₁),[G₁,G₂)…[G_f-1,G_f) Wherein G is₀＝0；

Fifth, according to the calculation result of step four, consider [ G ]₀,G₁),[G₁,G₂)…[G_f-1,G_f) Interval of values and T_iRelationship of the amount of overload Δ L: if delta L is located at [ G ]_p,G_p+1) Value interval, k ∈ (0,1,2 … f-1), as G_p+1Adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification; if DeltaL is greater than or equal to G_fPress a G_fAnd adjusting the in-station mode by the corresponding load transfer combination method, and starting a load flow calculation module for verification.

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