CN118572770A - Method, device and apparatus for evaluating transient power angle stability of power system - Google Patents

Abstract

The present disclosure provides a method, device and equipment for evaluating the transient power angle stability of an electric power system, wherein the method comprises: establishing an equivalent circuit of an initial integrated system based on the electric power system to be evaluated and a pumped storage unit of a preset type connected to the electric power system to be evaluated; determining an equivalent circuit of a current integrated system corresponding to the current working condition based on the equivalent circuit of the initial integrated system and using the preset type and current working condition of the pumped storage unit; in response to a fault in the current integrated system under the current working condition, respectively obtaining parameter values of a first state parameter of the current integrated system before the fault and parameter values of a second state parameter at different stages of fault handling; in response to determining that the transient power angle of the electric power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculating the stability margin of the electric power system to be evaluated. Evaluation using the method disclosed in the present disclosure is simple and effective.

Description

Method, device and apparatus for evaluating transient power angle stability of power system

Technical Field

The present disclosure relates to the technical field of power system stability analysis, and in particular to a method, device, electronic device, non-transient computer-readable storage medium, and computer program product for evaluating transient power angle stability of a power system.

Background Art

As we all know, pumped storage (hereinafter referred to as pumped storage) is a stable and reliable large-capacity energy storage technology and is currently the main means of energy storage. As the proportion of new energy stations connected to the power grid gradually increases, a large number of pumped storage units are connected to the power system to smooth the volatility of new energy power generation and improve the peak-shaving capacity of the power system.

However, with the access of a high proportion of pumped storage units, the equivalent subtransient reactance and potential of the original synchronous generators in the power system are affected, the power characteristics of the power system change, and the stability of the power system (especially the transient power angle stability) may deteriorate under certain possible fault conditions. Therefore, it is necessary to conduct research on the transient power angle stability analysis of the power system under the access of a high proportion of pumped storage units.

In the current related technologies, the solutions for "transient power angle stability analysis of power systems with high proportion of pumped storage units connected" mainly involve time domain simulation methods, phase trajectory methods and energy function methods. However, the above-mentioned existing technology solutions have at least the problems of heavy computational burden, lack of physical explanation of the solution results, inability to give quantitative results, and difficulty in popularization and application.

Summary of the invention

The present disclosure provides a method, an apparatus, an electronic device, a non-transient computer-readable storage medium, and a computer program product for evaluating the transient power angle stability of an electric power system, so as to solve the defects in the prior art.

The present disclosure provides a method for evaluating transient power angle stability of an electric power system, comprising:

Based on the power system to be evaluated and the pumped storage units of preset types connected to the power system to be evaluated, an equivalent circuit of the initial comprehensive system is established; wherein the power system to be evaluated includes multiple synchronous generator sets, multiple new energy power generation stations and a direct current transmission system; the preset types of the pumped storage units include fixed speed type and variable speed type;

Based on the equivalent circuit of the initial integrated system, using the preset type and current operating condition of the pumped storage unit, determining the equivalent circuit of the current integrated system corresponding to the current operating condition;

In response to a fault occurring in the current integrated system under the current working condition, respectively obtaining parameter values of a first state parameter of the current integrated system before the fault and parameter values of a second state parameter at different stages of fault handling;

In response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, the stability margin of the power system to be evaluated is calculated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

The present disclosure also provides a device for evaluating the transient power angle stability of an electric power system, comprising:

The initial equivalent circuit construction module is configured to: establish an equivalent circuit of an initial comprehensive system based on a power system to be evaluated and a pumped storage unit of a preset type connected to the power system to be evaluated; wherein the power system to be evaluated includes a plurality of synchronous generator sets, a plurality of new energy power generation stations and a direct current transmission system; and the preset types of the pumped storage units include a fixed speed type and a variable speed type;

The current equivalent circuit construction module is configured to: determine the equivalent circuit of the current integrated system corresponding to the current operating condition based on the equivalent circuit of the initial integrated system and using the preset type and current operating condition of the pumped storage unit;

The system parameter acquisition module is configured to: in response to a fault occurring in the current integrated system under the current working condition, respectively acquire parameter values of a first state parameter of the current integrated system before the fault and parameter values of a second state parameter at different stages of fault handling;

The stability analysis module is configured to: in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculate the stability margin of the power system to be evaluated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

The present disclosure also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for evaluating the transient power angle stability of an electric power system as described in any one of the above is implemented.

The present disclosure also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for evaluating the transient power angle stability of an electric power system as described in any one of the above is implemented.

The present disclosure also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above methods for evaluating the transient power angle stability of an electric power system.

As described above, the method provided by the present disclosure for evaluating the transient power angle stability of the power system is based on the dynamic characteristics analysis of the pumped storage unit, and the pumped storage unit is incorporated into the equal area criterion analysis framework to study the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated. Specifically, the present disclosure analyzes the dynamic characteristics of the fixed-speed and variable-speed pumped storage units under the current working conditions, and then obtains their equivalent circuits; and connects them with the equivalent circuits of the remaining components of the power system to be evaluated, so as to obtain the equivalent circuit of the current integrated system and the corresponding electromagnetic power expression (which will be described in subsequent embodiments). Furthermore, by analyzing the changes in the electromagnetic power expression before and after the power fault to be evaluated, the power angle acceleration and the maximum power angle deceleration area of the power to be evaluated can be calculated, and then the power angle margin of the power system to be evaluated can be obtained, which is used as an indicator to measure the transient power angle stability of the power to be evaluated, and is used to quantitatively calculate the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated.

In summary, the method for evaluating the transient power angle stability of the power system provided by the above embodiment of the present disclosure can fully consider the influence of different types of pumped storage units and different operating conditions on the transient power angle stability of the system. And because the adopted "equal area criterion" has the advantages of simple calculation and clear mechanism, the method of the embodiment of the present disclosure not only has a small calculation burden, the physical interpretation of the solution result is clear and quantitative, but also has a wide range of application and is easy to implement.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the present disclosure or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a flow chart of a method for evaluating transient power angle stability of a power system provided by an embodiment of the present disclosure;

2 is a schematic diagram of an equivalent circuit of a first power external characteristic of the fixed-speed pumped-storage unit provided in an embodiment of the present disclosure when operating in a power generation condition or a pumping condition;

3 is a schematic diagram of an equivalent circuit of a first power external characteristic of the fixed-speed pumped storage unit provided in an embodiment of the present disclosure operating in a phase-adjusting condition;

4 is a schematic diagram of an equivalent circuit of the first power external characteristic of the variable speed pumped storage unit provided in an embodiment of the present disclosure operating under different working conditions;

FIG5 is a schematic diagram of a paradigm system structure of the power system to be evaluated provided in an embodiment of the present disclosure;

FIG6 is a schematic diagram of an external characteristic equivalent circuit of the wind farm generator set provided by an embodiment of the present disclosure;

FIG7 is a schematic diagram of an external characteristic equivalent circuit of a DC power transmission system provided by an embodiment of the present disclosure;

FIG8 is an equivalent circuit of the initial integrated system provided by an embodiment of the present disclosure;

9 is a schematic diagram of the change of the electromagnetic power curve of the power system to be evaluated before and after a fault when the pumped storage unit provided in an embodiment of the present disclosure is working under power generation conditions;

FIG10 is a schematic diagram of the structure of a device for evaluating transient power angle stability of a power system provided by an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of the structure of an electronic device provided by the present disclosure.

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the technical solutions in the present disclosure will be clearly and completely described below in conjunction with the drawings in the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

Summary of the invention concept:

After research, the inventors of the present disclosure have found that pumped storage units can be divided into two types: fixed-speed pumped storage and variable-speed pumped storage. Both types of pumped storage can operate under three working conditions: power generation, pumping, and phase adjustment. For fixed-speed pumped storage units, their structure and operating characteristics are the same as those of synchronous motors, so they can be equivalent to synchronous generators, synchronous motors, and synchronous phase regulators under three working conditions. Therefore, the power angle characteristics of fixed-speed pumped storage are the same as those of traditional synchronous machines, and its access will directly affect the equivalent model of the synchronous machine in the system; in comparison, the variable-speed pumped storage unit is equivalent to an asynchronous motor, which can be equivalent to an asynchronous generator, an asynchronous motor, and an asynchronous phase regulator under three working conditions. Therefore, its power angle characteristics are different from those of traditional synchronous machines, but it can indirectly affect the electromagnetic power of the synchronous machine by affecting the power balance of the power system.

Based on this, the inventors of the present disclosure have found through further research that the reason for the problems of the prior art is that the core of the time domain simulation method is to obtain the solution of the power system dynamics equation based on the numerical solution method. Although relatively accurate numerical results can be obtained, the "numerical solution-based" method also leads to a large computational burden and a lack of physical explanation of the solution results. The phase trajectory method mainly reflects the evolution process of system stability more intuitively by describing the relative changes between the power angle and the angular velocity, so it is impossible to give a quantitative result. The energy function law is based on Lyapunov theory, which quantitatively judges the stability of the system by calculating the energy and critical energy value at the moment of fault, but the construction of the energy function is often very difficult, which makes it difficult to popularize and apply.

Furthermore, the inventors of the present disclosure have also found through research that the "equal area criterion" is widely used in the transient power angle stability analysis of the equivalent single synchronous machine-infinite power system due to its advantages of simple calculation and clear mechanism. However, there is no precedent for applying it to the stability analysis of the power system with pumped storage units connected.

In view of this, the inventors of the present disclosure consider using the "equal area criterion" to evaluate the transient power angle stability of different types of pumped storage units after they are connected to the power system based on the structure and operating characteristics of the pumped storage unit. Specifically, the inventors of the present disclosure provide a solution for evaluating the transient power angle stability of the power system as described in the following embodiment.

Example:

The following describes the scheme for evaluating the transient power angle stability of a power system disclosed in the present invention in conjunction with the accompanying drawings.

FIG1 is a flow chart of a method for evaluating the transient power angle stability of a power system provided by an exemplary embodiment of the present disclosure. This embodiment can be applied to an electronic device (e.g., a server or a cloud computing platform). As shown in FIG1, the method for evaluating the transient power angle stability of a power system includes the following steps:

S110 , establishing an equivalent circuit of an initial integrated system based on the power system to be evaluated and a pumped storage unit of a preset type connected to the power system to be evaluated.

Among them, the power system to be evaluated includes multiple synchronous generator sets, multiple new energy power generation stations and a direct current transmission system; the preset types of the pumped storage units include fixed speed type and variable speed type.

It should be noted that before executing step S110, the structure and components of the power system to be evaluated, the type of the preset type of pumped storage unit and the connection relationship with the power system to be evaluated and other related information can generally be obtained in advance; using this information, the equivalent circuit of the initial integrated system can be established. The specific implementation will be described below and will not be repeated here.

S120. Based on the equivalent circuit of the initial integrated system, and utilizing the preset type and current operating condition of the pumped storage unit, determine the equivalent circuit of the current integrated system corresponding to the current operating condition.

The current operating condition set refers to the operating condition at the current moment or can also be understood as the real-time operating condition.

S130. In response to a fault occurring in the current integrated system under the current operating condition, respectively obtaining parameter values of first state parameters of the current integrated system before the fault and parameter values of second state parameters at different stages of fault handling.

The present disclosure does not limit the type of "fault". For example, it may include but is not limited to DC output system locking.

The present disclosure does not limit the "different stages of fault handling". For example, when the fault is a DC output system lockout, the different stages of fault handling may include a capacitor removal stage and a system power-off stage. Accordingly, the equivalent circuit of the current integrated system may change accordingly to match the different stages of fault handling.

The present disclosure does not limit the method of "obtaining" the "parameter value of the first state parameter and the parameter value of the second state parameter". For example, they can be collected from the current integrated system, or, if it is not convenient to collect, they can be calculated or estimated in a reasonable way.

S140. In response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculate the stability margin of the power system to be evaluated.

The stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

The judgment on the stability of the power system to be evaluated is implemented based on the "equal area criterion", and the specific implementation details will be described below and will not be repeated here.

As described above, the method provided by the present disclosure for evaluating the transient power angle stability of the power system is based on the dynamic characteristics analysis of the pumped storage unit, and the pumped storage unit is incorporated into the equal area criterion analysis framework to study the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated. Specifically, the present disclosure analyzes the dynamic characteristics of the fixed-speed and variable-speed pumped storage units under the current working conditions, and then obtains their equivalent circuits; and connects them with the equivalent circuits of the remaining components of the power system to be evaluated, so as to obtain the equivalent circuit of the current integrated system and the corresponding electromagnetic power expression (which will be described in subsequent embodiments). Furthermore, by analyzing the changes in the electromagnetic power expression before and after the power fault to be evaluated, the power angle acceleration and the maximum power angle deceleration area of the power to be evaluated can be calculated, and then the power angle margin of the power system to be evaluated can be obtained, which is used as an indicator to measure the transient power angle stability of the power to be evaluated, and is used to quantitatively calculate the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated.

In summary, the method for evaluating the transient power angle stability of the power system provided by the above embodiment of the present disclosure can fully consider the influence of different types of pumped storage units and different operating conditions on the transient power angle stability of the system. And because the adopted "equal area criterion" has the advantages of simple calculation and clear mechanism, the method of the embodiment of the present disclosure not only has a small calculation burden, the physical interpretation of the solution result is clear and quantitative, but also has a wide range of application and is easy to implement.

Based on the embodiment of FIG1 , as an optional implementation, when the preset type is a constant speed type, the multiple operating conditions include a power generation condition, a pumping condition, and a phase adjustment condition. When the preset type is a variable speed type, the multiple operating conditions include a power generation condition, a pumping condition, and a phase adjustment condition.

Based on the embodiment of FIG. 1 and the above-mentioned embodiments, as an optional embodiment, step S110 “based on the power system to be evaluated and the pumped storage unit of a preset type connected to the power system to be evaluated” can be implemented as follows:

Step 1) using the dynamic characteristics of the preset type of pumped storage unit under various working conditions, establish a first power external characteristic equivalent circuit corresponding to each working condition.

I. When the pumped storage unit is of fixed speed type, it can be equivalent to a synchronous generator, a synchronous motor and a synchronous phase regulator when operating in power generation, pumping and phase adjustment conditions.

Therefore, the dynamic characteristics of the fixed-speed pumped storage unit when operating under different working conditions can be described by the second-order differential equations described in the following calculation formulas (1) to (2):

P _e = E _Q U _D sinδ/x _d (2)

Among them, δ represents the actual power angle of the rotor of the pumped storage unit; ω represents the actual angular velocity of the rotor of the pumped storage unit; _ωb represents the angular velocity reference; _ωn represents the grid-connected angular velocity; J represents the inertia coefficient, _Pm represents the output mechanical power of the prime mover, _Pe represents the electromagnetic power; _EQ represents the subtransient potential of the synchronous machine; _xd represents the subtransient reactance of the synchronous machine.

Based on the above dynamic characteristics, when the fixed-speed pumped storage unit operates in the power generation condition, the value of the electromagnetic power is positive and the sub-transient reactance value is positive; when it operates in the pumping condition, the value of the electromagnetic power is negative and the sub-transient reactance value is negative. Therefore, as an optional example, the first power external characteristic equivalent circuit of the fixed-speed pumped storage unit when operating in the power generation condition or the pumping condition can be represented by the equivalent circuit shown in Figure 2, and the difference between the two conditions lies in the positive and negative value of the sub-transient reactance. As another optional example, when the fixed-speed pumped storage unit operates in the phase adjustment condition, the output active power of the pumped storage unit is 0, and only reactive power is emitted or absorbed. Therefore, the first power external characteristic equivalent circuit of the fixed-speed pumped storage unit operating in the phase adjustment condition can be approximately represented by the equivalent reactance _xp shown in Figure 3, and when it injects inductive reactive power into the power system to be evaluated, its value is negative; when it injects capacitive reactive power into the power system to be evaluated, its value is positive.

II. For the case where the pumped storage unit is of variable speed type, when it operates in power generation condition, pumping condition and phase adjustment condition respectively, it can be equivalent to an asynchronous generator, asynchronous motor and asynchronous phase regulator accordingly.

Since the control time scale of the control system of an asynchronous motor, whether it is a generator, motor or phase regulator, is much smaller than the rotor inertia time scale of a synchronous generator, it can be ignored when performing transient stability analysis.

Based on this, when the variable speed pumped storage unit operates in different working conditions, the corresponding first power external characteristic equivalent circuit can be represented by the parallel impedance model shown in Figure 4. Among them, r _p1 represents the equivalent resistance of active and reactive power; x _p1 represents the equivalent reactance of active and reactive power. When it operates in the power generation condition, r _p1 <0, x _p1 ＝0; when it operates in the pumping condition, r _p1 >0, x _p1 ＝0; when it operates in the phase adjustment condition and injects inductive reactive power into the system, r _p1 ＝0, x _p1 <0; when it operates in the phase adjustment condition and injects capacitive reactive power into the system, r _p1 ＝0, x _p1 >0.

Step 2) For multiple synchronous generator sets in the power system to be evaluated, single-machine equivalence is performed and nodes are eliminated using a preset network node elimination rule to obtain an equivalent synchronous generator set.

Step 3) aggregate multiple renewable energy power generation stations in the power system to be evaluated, and perform node elimination using a preset network node elimination rule to obtain an aggregated renewable energy power generation station.

In step 2) and step 3), the present disclosure does not limit the "preset network node elimination rule", for example, it may include but is not limited to the Kron Reduction method.

It should be noted that, through step 2) and step 3), the power system structure to be evaluated can be simplified into a paradigm system structure.

As an optional example, referring to FIG5 , the paradigm system structure may include a receiving system 1, a receiving system 2, a high-voltage direct current transmission system (HVDC), a high-voltage alternating current transmission system (HVAC), capacitors, transformers T1 to T3, a synchronous generator SG, a wind farm station, and a pumped storage unit PS. Referring to FIG5 , the "pumped storage unit access part" can be used to access the "first power external characteristic equivalent circuit" when constructing a system equivalent circuit in the future.

Step 4) using preset equivalent circuit construction rules to determine the second external characteristic equivalent circuit corresponding to the aggregated renewable energy power generation station and the third external characteristic equivalent circuit corresponding to the direct current transmission system.

As an optional example, assume that the aggregated renewable energy power generation station is the "wind farm station" in the example of Figure 5. Then, in the framework of synchronous machine transient stability analysis, the control bandwidth of the wind farm station generator set controller is much smaller than its generator set rotor, so its dynamic characteristics can be ignored. Under this premise, the external characteristics of the wind farm station generator set can be approximately equivalent to a power source, injecting different active and reactive powers into the power system to be evaluated at different stages of the power system fault to be evaluated.

Therefore, the negative variable impedance model shown in the following calculation formula (3) can be used to equate its power contribution to the power system to be evaluated.

Among them, r _W represents the equivalent resistance of the wind turbine generator set power characteristics; x _W represents the equivalent reactance of the wind turbine generator set power characteristics; P _W represents the active output of the wind turbine generator set; Q _W represents the reactive output of the wind turbine generator set.

In this example, based on the above analysis, the external characteristic equivalent circuit of the wind farm generator set may be as shown in FIG6 .

As another optional example, based on similar reasons to the previous example, ignoring the dynamic characteristics of the DC system, the DC system can be approximately equivalent to a constant power load, which can also be represented by an impedance model, as shown in the following equation (4):

Among them, r _D represents the equivalent resistance of the power characteristic of the DC transmission system; x _D represents the equivalent reactance of the power characteristic of the DC transmission system; P _D represents the active power transmitted by DC; Q _D represents the reactive power transmitted by DC.

In this example, based on the above analysis, the external characteristic equivalent circuit of the DC transmission system can be shown as shown in FIG7 .

Step 5) using the first power external characteristic equivalent circuit, the second external characteristic equivalent circuit, the third external characteristic equivalent circuit and the equivalent synchronous generator set to establish an equivalent circuit of the initial integrated system.

Among them, as an optional example, referring to the exemplary system structure of Figure 5, the first power external characteristic equivalent circuit, the second external characteristic equivalent circuit, the third external characteristic equivalent circuit and the equivalent synchronous generator set are adaptively matched and connected to obtain the equivalent circuit of the initial integrated system as shown in Figure 8.

Referring to the example of Figure 8, based on the preset type of the pumped storage unit, 6 operating conditions (i.e., Model 1 to 6) can be matched and adaptively adjusted to 6 equivalent circuits (i.e., 6 equivalent circuits of the current integrated system corresponding to the current operating conditions); how to implement the adjustment will be described below and will not be repeated here.

Based on the above embodiments and implementation methods, as an optional implementation method, step S120 "determining the equivalent circuit of the current integrated system corresponding to the current operating condition by using the preset type and current operating condition of the pumped storage unit based on the equivalent circuit of the initial integrated system" may include the following situations:

Operating condition Model1, in response to the preset type of the pumped storage unit being a constant speed type and the current operating condition being a power generation condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is merged with the circuit of the equivalent synchronous generator set to obtain the equivalent circuit of the current integrated system corresponding to the current operating condition.

Operating condition Model2, in response to the preset type of the pumped storage unit being a constant speed type and the current operating condition being a pumping condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is merged with the circuit of the equivalent synchronous generator set to obtain the equivalent circuit of the current integrated system corresponding to the current operating condition.

Operating condition Model3, in response to the preset type of the pumped storage unit being a constant speed type, and the current operating condition being a phase-adjusting condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is adjusted to a parallel reactance to obtain the equivalent circuit of the current integrated system corresponding to the current operating condition.

Operating condition Model 4, in response to the preset type of the pumped storage unit being a variable speed type and the current operating condition being a power generation condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is adjusted to a parallel resistor to obtain the equivalent circuit of the current integrated system corresponding to the current operating condition.

Working condition Model5, in response to the preset type of the pumped storage unit being a variable speed type and the current working condition being a pumping working condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is adjusted to a parallel resistor to obtain the equivalent circuit of the current integrated system corresponding to the current working condition.

Operating condition Model6, in response to the preset type of the pumped storage unit being a variable speed type, and the current operating condition being a phase-adjusting condition, the equivalent circuit corresponding to the pumped storage unit in the equivalent circuit of the initial integrated system is adjusted to a parallel reactance to obtain the equivalent circuit of the current integrated system corresponding to the current operating condition.

Based on the above embodiments and implementation modes, as an optional implementation mode, the first state parameter and the second parameter include:

The subtransient potential of the equivalent synchronous generator set in the equivalent circuit of the current integrated system, the equivalent voltage of the power characteristic of the direct current transmission system, the complementary angle of the self-impedance angle, the complementary angle of the mutual impedance angle, the actual power angle of the rotor of the pumped storage unit, the sum of the subtransient reactance of the generator and the reactance of the export transformer, the equivalent resistance of the power characteristic of the aggregated new energy power generation station, the equivalent reactance of the power characteristic of the direct current transmission system, the equivalent resistance of the power characteristic of the direct current transmission system, the line reactance, the reactance of the shunt capacitor, the active output of the aggregated new energy power generation station, the active power of the direct current transmission system, the reactive power of the direct current transmission system, the reactive power _Qc of the shunt capacitor, the equivalent output reactance of the equivalent synchronous generator set and the pumped storage unit after the equivalent circuit is combined under the current operating conditions, and the active power and reactive power absorbed or emitted by the pumped storage unit under the current operating conditions.

Based on the above embodiments and implementation methods, as an optional implementation method, step S140 "calculating the stability margin of the power system to be evaluated in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system" may include the following steps:

Step i): based on the parameter value of the first state parameter and the equivalent circuit of the current integrated system, a first electromagnetic power curve of the current integrated system before a fault is determined using a preset electromagnetic power calculation rule.

Wherein, without considering the connection of the pumped storage unit to the power system to be evaluated, the equivalent electromagnetic power _PeS of the power system to be evaluated can be determined by the following calculation formulas (5) to (7):

Wherein, Z _SS and Z _SS-1 both represent the self-impedance of the current integrated system; Z _SR and Z _SR-1 both represent the mutual impedance of the current integrated system; the meanings of the remaining symbols in formulas (5) to (7) are as follows: the subtransient potential Eq of the equivalent synchronous generator set in the equivalent circuit of the current integrated system, the equivalent voltage U _D of the power characteristic of the DC transmission system, the complementary angle α _SS of the self-impedance angle, the complementary angle α _SR of the mutual impedance angle, the actual power angle δ of the rotor of the pumped storage unit, the sum of the subtransient reactance of the generator and the reactance of the export transformer x _Td-TS , the power characteristic equivalent resistance r _W of the aggregated renewable energy power station, the power characteristic equivalent reactance x _D of the DC transmission system, the power characteristic equivalent resistance r _D of the DC transmission system, the line reactance x _L , the reactance x _c of the shunt capacitor, the active output P _W of the aggregated renewable energy power station, the active power P _D of the DC transmission system, the reactive power Q _D of the DC transmission system, and the reactive power Qc of the shunt capacitor.

In the example of step i), when considering the connection of different types of pumped storage units, the self-impedance and mutual impedance of the equivalent circuit of the power system to be evaluated will change, thereby forming the equivalent circuit of the current integrated system; and thus the above calculation formulas (6) to (7) need to be modified adaptively to match the specific working conditions.

Specifically, according to the type of pumped storage unit and the current operating conditions, the modification rules of the impedance expression are as follows:

When the working condition is Mode 1:

At this time, the subtransient reactance value of the equivalent circuit of the fixed-speed pumped storage unit is greater than 0. By merging it with the equivalent synchronous generator set, jx _Td-Ts in the calculation formulas (6) and (7) is replaced by jx _Td-Ps1 .

Wherein, jx _Td-Ps1 represents the equivalent output reactance after the equivalent circuit of the equivalent synchronous generator set and the pumped storage unit is combined under the current operating condition.

When the working condition is Mode 2:

At this time, the subtransient reactance value of the equivalent circuit of the fixed-speed pumped storage unit is less than 0. By merging it with the equivalent synchronous generator unit, jx _Td-Ts in the calculation formulas (6) and (7) is replaced by jx _Td-Ps2 .

Wherein, jx _Td-Ps2 represents the equivalent output reactance after the equivalent circuit of the equivalent synchronous generator set and the pumped storage unit is combined under the current operating condition.

When the working condition is Mode 3:

At this time, the equivalent circuit of the fixed-speed pumped storage unit is a parallel reactance. Since the size of the parallel reactance is determined by the reactive power generated by the phase regulator, the reactive term in equations (6) and (7) is modified from Q _D -Q _C to Q _D -Q _C -Q _P. Q _P represents the reactive power absorbed or generated by the fixed-speed pumped storage unit under the phase-shifting condition.

When the working condition is Mode 4:

At this time, the equivalent circuit of the variable speed pumped storage unit is a parallel resistor. Since the size of the parallel resistor is determined by the active power generated by the generator, the active term in the calculation formula (6) and (7) is modified from P _{W -PD} to P _{W -PD} + _PP1 . _PP1 represents the active power generated by the variable speed pumped storage unit under the power generation condition.

When the working condition is Mode 5:

At this time, the equivalent circuit of the variable speed pumped storage unit is a parallel resistor. Since the size of the parallel resistor is determined by the active power absorbed by the motor, the active term in the calculation formula (6) and (7) is modified from P _{W -PD} to P _{W -PD -PP1} . _-PP1 represents the active power absorbed by the variable speed pumped storage unit under pumping conditions.

When the working condition is Mode 6:

At this time, the equivalent circuit of the variable speed pumped storage unit is a parallel reactance. Since the size of the parallel reactance is determined by the reactive power generated or absorbed by the phase regulator, the reactive term in the expressions of calculation formulas (6) and (7) is modified from Q _D -Q _C to Q _D -Q _C -Q _P1 . _{Q P1} represents the reactive power absorbed or generated by the variable speed pumped storage unit under the phase modulation condition.

As described above, by using the above calculation formulas (5) to (7) and the corresponding adaptive modification rules for matching specific working conditions, based on the parameter values of the first state parameters obtained within a certain period of time, the first electromagnetic power curve of the current integrated system matching the current working condition before the fault can be calculated.

Step ii) in response to different stages of fault handling, updating the equivalent circuit of the current integrated system to obtain updated equivalent circuits corresponding to different stages of fault handling.

It should be noted that, since fault conditions are complex and changeable, the handling paradigm for each fault condition is also different. When the handling method requires modification or adjustment of the equivalent circuit of the current integrated system, the equivalent circuit of the current integrated system can be updated according to the handling modification.

Step iii) based on the parameter value of the second state parameter and the updated equivalent circuit, using the preset electromagnetic power calculation rule, determine the second electromagnetic power curve of the current integrated system corresponding to different stages of fault handling.

The preset electromagnetic power calculation rules can be adaptively adjusted with reference to the example content of the aforementioned step i). Specifically, since the updated equivalent circuit is different from the "equivalent circuit of the current integrated system" before the fault, when modifying the relevant items of the calculation formulas (6) to (7) corresponding to different working conditions in executing similar step i), it is necessary to make further adjustments based on step i).

Then, based on the parameter value of the second state parameter obtained within a certain period of time (for example, covering the period from the beginning to the end of fault handling), the second electromagnetic power curve corresponding to the current integrated system at different stages of fault handling can be calculated.

Step iv) using the first electromagnetic power curve and the second electromagnetic power curve, to calculate the power angle acceleration area A _acc and the power angle maximum deceleration area A _de of the current integrated system.

As an optional example, referring to FIG. 9 , since the power angle acceleration area and the power angle maximum deceleration area are areas defined by the first electromagnetic power curve and the second electromagnetic power curve in the same coordinate system, the integral method can be used for calculation.

Step v) In response to the maximum power angle deceleration area being greater than the power angle acceleration area, determining that the transient power angle of the power system to be evaluated is stable, and calculating the difference between the maximum power angle deceleration area and the power angle acceleration area to obtain the stability margin.

As an optional example, the following calculation formula (8) may be used to determine the transient power angle stability of the power system to be evaluated:

A _dec >A _acc (8)

When the transient power angle of the power system to be evaluated is determined to be stable, the stability margin η can be determined using the following calculation formula (9):

η＝ _Adec - _Aacc (9)

Among them, A _acc represents the power angle acceleration area; A _de represents the power angle maximum deceleration area.

As described above, the method provided by the present disclosure for evaluating the transient power angle stability of the power system is based on the dynamic characteristics analysis of the pumped storage unit, and the pumped storage unit is incorporated into the equal area criterion analysis framework to study the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated. Specifically, the present disclosure analyzes the dynamic characteristics of the fixed-speed and variable-speed pumped storage units under the current working conditions, and then obtains their equivalent circuits; and connects them with the equivalent circuits of the remaining components of the power system to be evaluated, so as to obtain the equivalent circuit of the current integrated system and the corresponding electromagnetic power expression (which will be described in subsequent embodiments). Furthermore, by analyzing the changes in the electromagnetic power expression before and after the power fault to be evaluated, the power angle acceleration and the maximum power angle deceleration area of the power to be evaluated can be calculated, and then the power angle margin of the power system to be evaluated can be obtained, which is used as an indicator to measure the transient power angle stability of the power to be evaluated, and is used to quantitatively calculate the impact of the access of the pumped storage unit on the transient power angle stability of the power system to be evaluated.

In summary, the method for evaluating the transient power angle stability of the power system provided by the above embodiment of the present disclosure can fully consider the influence of different types of pumped storage units and different operating conditions on the transient power angle stability of the system. And because the adopted "equal area criterion" has the advantages of simple calculation and clear mechanism, the method of the embodiment of the present disclosure not only has a small calculation burden, the physical interpretation of the solution result is clear and quantitative, but also has a wide range of application and is easy to implement.

Verification example:

The specific implementation of the present invention is explained by a calculation example of a constant speed pumped storage unit operating under different working conditions. After equivalent transformation, the calculation example can be converted into the exemplary structure shown in Figure 5. It is assumed that the DC system is suddenly locked during normal operation of the system.

The system parameters are set as follows: the base capacity of the system is S _base = 100MW, the capacitor removal time t _c = 0.1s, the removal amount is 80%, the machine cutting time is t ₁ = 0.2s, and the machine cutting amount is 60p.u.

Before DC blocking occurs, the electromagnetic power expression of the system under normal operation when the pumped storage unit is in Mode 1 to Model 3 can be obtained according to equations (5) to (7). Subsequently, the power changes before and after the capacitor is removed after blocking are further analyzed, and the modulus values of self-impedance and mutual impedance are corrected to obtain the electromagnetic power expression of the pumped storage unit at different fault stages under different operating conditions. By analyzing the changes in the electromagnetic power curve, the acceleration and deceleration areas of the system can be obtained as a basis for stability judgment.

Taking the pumped storage unit working in power generation condition as an example, the change of its electromagnetic power curve is shown in Figure 9. Referring to Figure 9, under the normal operation state before the DC lockout occurs, the electromagnetic power curve of the system equivalent synchronous machine is At this time, the mechanical power of the prime mover is The power angle at the normal operating point is δ ₀ . Subsequently, the system undergoes DC blocking, and the electromagnetic power curve drops to The generator rotor begins to accelerate and the power angle increases. When it increases to δ _c , the capacitor is cut off and the electromagnetic power curve rises back to The rotor continues to accelerate until the moment t ₁ = 0.2s, when the system cuts off. Then, when the power angle reaches δ ₂ , the rotor begins to decelerate, and the first area in FIG9 is the acceleration area A _acc . Further, the rotor enters the deceleration process until the power angle reaches δ _cr , the rotor speed is 0, and the second area is the maximum deceleration area A _dec .

Based on the above method, according to the power curve and according to the calculation formulas (8) to (9), the acceleration and deceleration areas of the system of the constant speed pumped storage unit under three working conditions are determined. After calculation, the system is stable under the three working conditions. Therefore, the stability margin values of the three working conditions can be obtained, as shown in Table 1.

Table 1 Transient power angle stability margin of the system under different operating conditions of pumped storage units

It can be seen from the above table that when the system is DC locked, under the premise of a certain amount of machine cutting, the stability margin of the system is the highest under the pumping condition, followed by the phase adjustment condition, and the lowest under the power generation condition. This is because after the DC lock occurs, the load level of the system drops sharply, the generator outputs excess active power, and a large power imbalance is generated. However, because the active power level of the equivalent machine is relatively low under the pumping mode, the imbalance is smaller than that of other conditions. Therefore, the transient power angle stability is relatively good, and the qualitative analysis is consistent with the quantitative calculation results; thereby verifying the effectiveness of the method for evaluating the transient power angle stability of the power system provided by the embodiment of the present disclosure.

The following is a description of the device for evaluating the transient power angle stability of an electric power system provided by the present disclosure. The device for evaluating the transient power angle stability of an electric power system described below and the method for evaluating the transient power angle stability of an electric power system described above can be referenced to each other.

FIG10 is a schematic diagram of a structure of a device for evaluating the transient power angle stability of a power system provided by an exemplary embodiment of the present disclosure. As shown in FIG10 , the device for evaluating the transient power angle stability of a power system includes:

The initial equivalent circuit construction module 210 is configured to: establish an equivalent circuit of an initial comprehensive system based on the power system to be evaluated and the pumped storage units of a preset type connected to the power system to be evaluated; wherein the power system to be evaluated includes a plurality of synchronous generator sets, a plurality of new energy power generation stations and a direct current transmission system; and the preset types of the pumped storage units include a fixed speed type and a variable speed type;

The current equivalent circuit construction module 220 is configured to: determine the equivalent circuit of the current integrated system corresponding to the current operating condition based on the equivalent circuit of the initial integrated system and using the preset type and current operating condition of the pumped storage unit;

The system parameter acquisition module 230 is configured to: in response to a fault occurring in the current integrated system under the current working condition, respectively acquire parameter values of a first state parameter of the current integrated system before the fault, and parameter values of a second state parameter at different stages of fault handling;

The stability analysis module 240 is configured to: in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculate the stability margin of the power system to be evaluated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

Figure 11 illustrates a schematic diagram of the physical structure of an electronic device. As shown in Figure 11, the electronic device may include: a processor (processor) 810, a communication interface (Communications Interface) 820, a memory (memory) 830 and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call the logic instructions in the memory 830 to execute a method for evaluating the transient power angle stability of the power system, the method comprising: establishing an equivalent circuit of an initial integrated system based on the power system to be evaluated and a pumped storage unit of a preset type connected to the power system to be evaluated; wherein the power system to be evaluated includes multiple synchronous generator sets, multiple new energy power generation stations and a direct current transmission system; the preset types of the pumped storage units include fixed speed type and variable speed type; based on the equivalent circuit of the initial integrated system, using the preset type and current operating condition of the pumped storage unit, determining the equivalent circuit of the current integrated system corresponding to the current operating condition; in response to a fault occurring in the current integrated system under the current operating condition, respectively obtaining parameter values of a first state parameter of the current integrated system before the fault and parameter values of a second state parameter at different stages of fault handling; in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter values of the first state parameter, the parameter values of the second state parameter and the equivalent circuit of the current integrated system, calculating the stability margin of the power system to be evaluated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present disclosure is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

On the other hand, the present disclosure also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method provided by the above methods for evaluating the transient power angle stability of the power system, the method including: based on the power system to be evaluated and the pumped storage unit of a preset type connected to the power system to be evaluated, establishing an equivalent circuit of an initial comprehensive system; wherein the power system to be evaluated includes multiple synchronous generator sets, multiple new energy power generation stations and a direct current transmission system; the preset types of the pumped storage unit include fixed speed type and variable speed type; based on the initial comprehensive system The equivalent circuit of the pumped storage unit is determined by using the preset type and current operating condition of the pumped storage unit to determine the equivalent circuit of the current integrated system corresponding to the current operating condition; in response to a fault in the current integrated system under the current operating condition, the parameter values of the first state parameters of the current integrated system before the fault and the parameter values of the second state parameters at different stages of fault handling are respectively obtained; in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter values of the first state parameters, the parameter values of the second state parameters and the equivalent circuit of the current integrated system, the stability margin of the power system to be evaluated is calculated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

On the other hand, the present disclosure also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the method for evaluating the transient power angle stability of an electric power system provided by the above-mentioned methods, the method comprising: establishing an equivalent circuit of an initial comprehensive system based on the electric power system to be evaluated and a pumped-storage unit of a preset type connected to the electric power system to be evaluated; wherein the electric power system to be evaluated comprises a plurality of synchronous generating units, a plurality of new energy power generation stations and a direct current transmission system; the preset types of the pumped-storage units comprise a fixed speed type and a variable speed type; based on the equivalent circuit of the initial comprehensive system, using the pumped-storage unit According to the preset type and current operating condition, an equivalent circuit of the current integrated system corresponding to the current operating condition is determined; in response to a fault in the current integrated system under the current operating condition, parameter values of a first state parameter of the current integrated system before the fault and parameter values of a second state parameter at different stages of fault handling are respectively obtained; in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, a stability margin of the power system to be evaluated is calculated, wherein the stability margin is used to characterize the transient power angle stability of the power system to be evaluated.

The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative work.

Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims (10)

1. A method for assessing transient power angle stability of an electrical power system, comprising:

Establishing an equivalent circuit of an initial integrated system based on a power system to be evaluated and a preset type pumping and accumulating unit connected with the power system to be evaluated; the power system to be evaluated comprises a plurality of synchronous generator sets, a plurality of new energy power generation stations and a direct current transmission system; the preset types of the pumping and accumulating unit comprise a constant speed type and a variable speed type;

Based on the equivalent circuit of the initial comprehensive system, determining the equivalent circuit of the current comprehensive system corresponding to the current working condition by utilizing the preset type and the current working condition of the pumping and accumulating unit;

Responding to the occurrence of a fault of the current comprehensive system under the current working condition, and respectively acquiring the parameter value of a first state parameter of the current comprehensive system before the fault and the parameter value of a second state parameter of different stages of fault treatment;

And in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculating a stability margin of the power system to be evaluated, wherein the stability margin is used for representing the transient power angle stability of the power system to be evaluated.

2. The method according to claim 1, wherein the establishing an equivalent circuit of the initial integrated system based on the electric power system to be evaluated and a preset type of pumping and accumulating unit connected to the electric power system to be evaluated comprises:

Establishing a first power external characteristic equivalent circuit corresponding to each working condition by utilizing the dynamic characteristics of the preset type pumping and accumulating unit under multiple working conditions;

Performing single-machine equivalence on a plurality of synchronous generator sets in the power system to be evaluated, and performing node elimination by using a preset network node elimination rule to obtain an equivalent synchronous generator set;

Performing station aggregation on a plurality of new energy power generation stations in the power system to be evaluated, and executing node elimination by using a preset network node elimination rule to obtain an aggregated new energy power generation station;

determining a second external characteristic equivalent circuit corresponding to the new energy aggregation power generation station and a third external characteristic equivalent circuit corresponding to the direct current transmission system by utilizing a preset equivalent circuit construction rule;

and establishing an equivalent circuit of the initial comprehensive system by using the first external characteristic equivalent circuit, the second external characteristic equivalent circuit, the third external characteristic equivalent circuit and the equivalent synchronous generator set.

3. The method of claim 2, wherein the step of determining the position of the substrate comprises,

Under the condition that the preset type is constant speed, the multiple working conditions comprise a power generation working condition, a water pumping working condition and a phase modulation working condition;

under the condition that the preset type is variable speed, the multiple working conditions comprise a power generation working condition, a water pumping working condition and a phase modulation working condition.

4. The method according to claim 2, wherein the determining the equivalent circuit of the current integrated system corresponding to the current operating condition using the preset type of the pumping and accumulating unit and the current operating condition based on the equivalent circuit of the initial integrated system includes:

Responding to the preset type of the pumping and accumulating unit as a constant speed type and the current working condition as a power generation working condition, combining the equivalent circuit corresponding to the pumping and accumulating unit with the circuit of the equivalent synchronous generator unit in the equivalent circuit of the initial comprehensive system to obtain the equivalent circuit of the current comprehensive system corresponding to the current working condition;

Responding to the preset type of the pumping and accumulating unit as a constant speed type and the current working condition as a pumping working condition, merging the equivalent circuit corresponding to the pumping and accumulating unit with the circuit of the equivalent synchronous generator unit in the equivalent circuit of the initial comprehensive system to obtain the equivalent circuit of the current comprehensive system corresponding to the current working condition;

responding to the preset type of the pumping and accumulating unit as a constant speed type and the current working condition as a phase modulation working condition, and adjusting the equivalent circuit corresponding to the pumping and accumulating unit into a parallel reactance in the equivalent circuit of the initial comprehensive system to obtain the equivalent circuit of the current comprehensive system corresponding to the current working condition;

Responding to the fact that the preset type of the pumping and accumulating unit is variable speed type and the current working condition is power generation working condition, adjusting an equivalent circuit corresponding to the pumping and accumulating unit in an equivalent circuit of the initial comprehensive system to be parallel resistance to obtain an equivalent circuit of the current comprehensive system corresponding to the current working condition;

responding to the fact that the preset type of the pumping and accumulating unit is variable speed type and the current working condition is pumping working condition, adjusting an equivalent circuit corresponding to the pumping and accumulating unit in an equivalent circuit of the initial comprehensive system to be parallel resistance to obtain an equivalent circuit of the current comprehensive system corresponding to the current working condition;

And in response to the preset type of the pumping and accumulating unit being a variable speed type and the current working condition being a phase modulation working condition, adjusting an equivalent circuit corresponding to the pumping and accumulating unit in an equivalent circuit of the initial integrated system to be a parallel reactance to obtain an equivalent circuit of the current integrated system corresponding to the current working condition.

5. The method of claim 1, wherein the first state parameter, the second parameter, comprise:

The method comprises the steps of combining a secondary transient potential of an equivalent synchronous generator set in an equivalent circuit of a current comprehensive system, a power characteristic equivalent voltage of a direct current transmission system, a complementary angle of a self-impedance angle, a complementary angle of a mutual impedance angle, an actual power angle of a rotor of a pumping and accumulating unit, a sum of a secondary transient reactance of a generator and an output transformer reactance, an equivalent resistance of a power characteristic of a power station of a new energy power generation station, an equivalent reactance of a power characteristic of the direct current transmission system, an equivalent resistance of a line reactance, a reactance of a shunt capacitor, an active output of the power station of the new energy power generation station, an active power of the direct current transmission system, reactive power of a shunt capacitor, an equivalent output reactance of the equivalent synchronous generator set and the equivalent circuit of the pumping and accumulating unit under the current working condition, and absorbing or generating active power and reactive power of the pumping and accumulating unit under the current working condition.

6. The method of claim 1, wherein calculating a stability margin of the power system under evaluation in response to determining that the power system under evaluation is stable in terms of the parameter value of the first state parameter, the parameter value of the second state parameter, and the equivalent circuit of the current integrated system comprises:

Determining a first electromagnetic power curve of the current comprehensive system before a fault by utilizing a preset electromagnetic power calculation rule based on the parameter value of the first state parameter and an equivalent circuit of the current comprehensive system;

Responding to different fault treatment stages, and updating the equivalent circuit of the current integrated system to obtain updated equivalent circuits corresponding to the different fault treatment stages;

determining a second electromagnetic power curve of the current integrated system corresponding to different stages of fault handling by using the preset electromagnetic power calculation rule based on the parameter value of the second state parameter and the updated equivalent circuit;

Calculating the power angle acceleration area and the power angle maximum deceleration area of the current integrated system by using the first electromagnetic power curve and the second electromagnetic power curve;

And determining that the transient power angle of the power system to be evaluated is stable in response to the fact that the maximum power angle deceleration area is larger than the power angle acceleration area, and calculating the difference value between the maximum power angle deceleration area and the power angle acceleration area to obtain the stability margin.

7. An apparatus for assessing transient power angle stability of an electrical power system, comprising:

An initial equivalent circuit construction module configured to: establishing an equivalent circuit of an initial integrated system based on a power system to be evaluated and a preset type pumping and accumulating unit connected with the power system to be evaluated; the power system to be evaluated comprises a plurality of synchronous generator sets, a plurality of new energy power generation stations and a direct current transmission system; the preset types of the pumping and accumulating unit comprise a constant speed type and a variable speed type;

the current equivalent circuit construction module is configured to: based on the equivalent circuit of the initial comprehensive system, determining the equivalent circuit of the current comprehensive system corresponding to the current working condition by utilizing the preset type and the current working condition of the pumping and accumulating unit;

A system parameter acquisition module configured to: responding to the occurrence of a fault of the current comprehensive system under the current working condition, and respectively acquiring the parameter value of a first state parameter of the current comprehensive system before the fault and the parameter value of a second state parameter of different stages of fault treatment;

a stability analysis module configured to: and in response to determining that the transient power angle of the power system to be evaluated is stable based on the parameter value of the first state parameter, the parameter value of the second state parameter and the equivalent circuit of the current integrated system, calculating a stability margin of the power system to be evaluated, wherein the stability margin is used for representing the transient power angle stability of the power system to be evaluated.

8. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method for assessing transient power angle stability of a power system according to any one of claims 1 to 6 when the program is executed by the processor.

9. A non-transitory computer readable storage medium having stored thereon a computer program, which when executed by a processor implements a method for assessing transient power angle stability of an electrical power system according to any of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that the computer program, when executed by a processor, implements a method for assessing transient power angle stability of an electrical power system according to any one of claims 1 to 6.