WO2014089959A1

WO2014089959A1 - Dynamic equivalence method for ac/dc hybrid large power grid based on engineering application

Info

Publication number: WO2014089959A1
Application number: PCT/CN2013/076698
Authority: WO
Inventors: 崔勇; 杨增辉
Original assignee: 上海市电力公司; 华东电力试验研究院有限公司; 国家电网公司
Priority date: 2012-12-10
Filing date: 2013-06-04
Publication date: 2014-06-19
Also published as: CN103036230A; CN103036230B

Abstract

A dynamic equivalence method for AC/DC hybrid large power grid based on engineering application belongs to the field of electric transformation and distribution. The power grid to be analyzed is divided into an external subarea power grid and an internal subarea power grid. The 500kV internal subarea power grid is fully simulated. The equivalent simplifications of the external subarea power grid and the low voltage internal subarea power grid are performed. The simplified external subarea power grid is obtained with equivalence generators by the dynamic equivalence method based on experience. The equivalent simplification of the low voltage internal subarea power grid is performed by the dynamic equivalence method based on physical equivalence, so as to obtain the final simplified internal subarea power grid. The effect of equivalence is checked after the equivalence of the external subarea power grid and the internal subarea power grid. By comparing the dynamic response characteristics in the same fault of the simplified system and that of the actual system, the validity of the whole dynamic equivalence principle and method is checked. The state parameters of the equivalence system and the number of the differential equations are reduced, and the efficiency of the analysis and calculation of the system is improved. The method can be widely applied for the fields of the analysis and calculation of the hybrid large power grid and the dispatching management of power grid.

Description

一种基于工程应用的交直流混联大电网的动态等值方法技术领域 Dynamic equivalent method for AC/DC hybrid large power grid based on engineering application

本发明属于变、配电领域，尤其涉及一种用于交直流混联大电网的动态等值方法。背景技术 The invention belongs to the field of variable and power distribution, and in particular relates to a dynamic equivalent method for AC/DC hybrid large power grid. Background technique

目前，我国电力***正在迅速发展，西电东送、南北互联、交直流联合输电以及大区域联网运行使得***日益庞大、复杂。即使进行离线机电暂态仿真时，都十分困难。因为大型电力***的动态元件数目较多，电网结构、特性、运行方式都很复杂， ***的暂态过程又是强非线性过程，所要求的计算机存储量很大，计算时间也较长，而计算机的机时、内存、数据准备等等往往不足以满足复杂的大型电力***的分析研究，还需知道整个***的全部信息 (包括***中所有元件的参数及运行状况)，从而显得困难重重。同时大量大功率电力电子设备，如：直流输电、 SVC ( Static Var Compensator, 静止无功补偿器）、 TCSC (Thyristor Controlled Series Compensation 晶闸管控制串联电容器补偿技术）设备和各种快速自动控制装置的广泛应用，使得电网的动态特性日趋复杂。 At present, China's power system is developing rapidly. The West-East Power Transmission, North-South Interconnection, AC-DC Combined Transmission, and large-area networking operations make the system increasingly large and complex. Even when performing offline electromechanical transient simulation, it is very difficult. Because the number of dynamic components of a large power system is large, the structure, characteristics, and operation mode of the power grid are complicated, and the transient process of the system is a strong nonlinear process. The required computer storage is large and the calculation time is long. The computer's machine time, memory, data preparation, etc. are often insufficient to meet the analysis and research of complex large-scale power systems. It is also difficult to know all the information of the whole system (including the parameters and operating conditions of all components in the system). At the same time, a large number of high-power power electronic equipment, such as: DC transmission, SVC (Static Var Compensator), TCSC (Thyristor Controlled Series Compensation thyristor control series capacitor compensation technology) equipment and a variety of rapid automatic control devices are widely used , making the dynamic characteristics of the grid increasingly complex.

基于基波、相量、序分析的机电暂态仿真软件在仿真 HVDC***和 FACTS 等电力电子设备均采用准稳态模型模拟，对其快速暂态特性和非线性元件引起的波形均不能反映；而电磁暂态分析软件由于其***所有元件的动态特性均采用微分方程表示使得其计算步长小、计算量大，因此，其仿真规模不大。对大规模电力***直接进行离线机电暂态分析、电磁暂态分析、在线动态安全评估及控制系统设计是非常困难的，所以有必要对其进行等值简化。 The electromechanical transient simulation software based on fundamental wave, phasor and sequence analysis uses pseudo-steady-state model simulation in the simulation of HVDC system and FACTS power electronic equipment. The fast transient characteristics and waveforms caused by nonlinear components cannot be reflected. The electromagnetic transient analysis software uses the differential equation to express the dynamic characteristics of all components of the system, so that the calculation step size is small and the calculation amount is large. Therefore, the simulation scale is not large. Direct offline electromechanical transient analysis, electromagnetic transient analysis, online dynamic safety assessment, and control system design for large-scale power systems are very difficult, so it is necessary to simplify them.

在分析研究大规模电力***动态行为时，往往也只是对其中一部分区域感兴趣，该部分区域需要详细描述以准确反映***的动态行为，通常称这一部分区域为内部*** （研究***）；而对其余部分区域，研究中只考虑其对内部***的影响，其本身不必详细描述，可进行降阶简化，该部分拟作简化的区域称为外部系统。 When analyzing the dynamic behavior of large-scale power systems, they are often only interested in some of them. This part needs to be described in detail to accurately reflect the dynamic behavior of the system. This part of the area is usually called the internal system (research system); In the rest of the area, only the impact on the internal system is considered in the study. It does not need to be described in detail, and the reduction can be simplified. The area to be simplified in this part is called the external system.

通过***简化可以突出主要矛盾，对于掌握研究***的主要特征，是十分必要的。这种保留研究***不变，而对外部***在保证其对研究***的动态响应不畸变的条件下，进行简化的过程称为动态等值。 Through system simplification, the main contradictions can be highlighted, and it is necessary to master the main features of the research system. need. This retention study system is unchanged, and the process of simplifying the external system under the condition that it guarantees that the dynamic response to the research system is not distorted is called dynamic equivalence.

历史上对大型电力***有许多经验性的动态等值方法。例如，将远离研究区域的发电机、负荷和网络用一台（或几台）等值的发电机或等值负荷表示，甚至简化为无穷大母线。相应地网络也简化，消去大量节点，原节点上的非线性负荷也移置到保留节点上去。但这些经验等值的缺点是- Historically there have been many empirical dynamic equivalent methods for large power systems. For example, generators, loads, and networks that are far from the study area are represented by one (or several) equivalent generators or equivalent loads, or even reduced to infinite bus bars. Accordingly, the network is also simplified, eliminating a large number of nodes, and the nonlinear load on the original node is also shifted to the reserved node. But the downside of these empirical equivalents is -

(1)极大地依赖于经验和主观判断； (1) greatly depends on experience and subjective judgment;

(2)方法粗糙、精度差、可能畸变原***的动态特征； (2) The method is rough, the precision is poor, and the dynamic characteristics of the original distortion system;

(3)所用的方法不***、不严格、不通用等。 (3) The method used is not systematic, not strict, not universal.

申请公布日为 2011年 12月 14日，申请公布号为 CN 102280884A的中国发明专利申请中公开了一种电网等值方法，其对待研究发电机组外部***进行简化，将远方复杂大电网和近端同母线机组分别等值为无穷大母线和动态机组。该方法适合应用于励磁***建模参数时域校核和 PSS参数优化等方面，能更好的反映外部***特性，在简化电力***仿真计算的同时，提高仿真计算精度。但其只能适用于发电机组的励磁***建模，无法应用到交直流混联大电网的动态等值计算中，亦为考虑到工程应用的问题。发明内容 The application publication date is December 14, 2011, and the Chinese invention patent application with the publication number CN 102280884A discloses a grid equivalent method, which simplifies the external system of the genset to be studied, and the remote complex large power grid and the near end The same bus unit is equivalent to infinite bus and dynamic unit. The method is suitable for the time domain calibration of excitation system modeling parameters and PSS parameter optimization. It can better reflect the external system characteristics and simplify the simulation calculation of power system while improving the accuracy of simulation calculation. However, it can only be applied to the excitation system modeling of the generator set, and can not be applied to the dynamic equivalent calculation of the AC/DC hybrid large power grid, and also considers the engineering application. Summary of the invention

本发明所要解决的技术问题是提供一种基于工程应用的交直流混联大电网的动态等值方法，其对区外电网和区内低压***进行等值简化，大大降低了等值 ***的状态量和微分方程数目，用对等值***的研究代替对原***的研究，这样既能节省人力和物力，抓住了主要矛盾，在保证必要精度的前提下可以极大地提高***分析计算效率，从而可以有效地对大规模电力***进行机电暂态仿真、电磁暂态仿真以及实时仿真的研究。 The technical problem to be solved by the present invention is to provide a dynamic equivalent method for AC/DC hybrid large power grid based on engineering application, which simplifies the equalization of the external power grid and the low voltage system in the region, and greatly reduces the state of the equivalent system. The quantity and the number of differential equations are replaced by the study of the equivalent system, which saves manpower and material resources, captures the main contradictions, and greatly improves the efficiency of system analysis and calculation under the premise of ensuring the necessary accuracy. Therefore, it is possible to effectively study the electromechanical transient simulation, electromagnetic transient simulation and real-time simulation of large-scale power systems.

本发明的技术方案是：提供一种基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态等值方法包括下列步骤- The technical solution of the present invention is: Providing a dynamic equivalent method for AC/DC hybrid large power grid based on engineering application, characterized in that the dynamic equivalence method comprises the following steps -

1-1、根据电网特性的不同、动态等值研究的对象以及等值后电网仿真研究的目标，将待分析电网划分为区外电网和区内电网两部分； 1-1. According to the different characteristics of the power grid, the object of dynamic equivalence research and the goal of post-equal power grid simulation research, the grid to be analyzed is divided into two parts: the extra-regional grid and the regional grid;

1-2 , 对区域内的 500kV 电网详细模拟，对区外电网以及区内的低电压网络进行等值简化； 1-2. Detailed simulation of the 500kV power grid in the area, and simplification of the external power grid and the low-voltage network in the area;

1-3、对区外电网采用基于经验的动态等值方法，将区外电网用等值发电机来表示，得到区外简化电网； 1-3. Using an empirically based dynamic equivalent method for the external power grid, the equivalent power generator for the external power grid To indicate that the grid is simplified outside the zone;

1-4、采用基于物理等效的动态等值方法，对区内低电压网络进行等值简化，得到最终的区内简化电网； 1-4. Using the dynamic equivalence method based on physical equivalent, the equivalent value of the low-voltage network in the area is simplified, and the simplified power grid in the final area is obtained.

1-5、在区外电网动态等值以及区内电网动态等值之后，均分别对等值效果进行校核； 1-5. After the dynamic equivalent of the power grid outside the district and the dynamic equivalent of the power grid in the district, the equivalent effects are checked separately;

1-6、通过比较简化电网与实际电网在相同故障下的动态响应曲线，校核整个动态等值原则和方法的有效性。 1-6. By comparing the dynamic response curves of the grid and the actual grid under the same fault, the validity of the whole dynamic equivalence principle and method is checked.

其所述的动态等值方法用等值简化电网代替原电网进行电磁暂态仿真和实时仿真研究，分析多回直流之间的相互影响，以及直流故障和直流落点附近交流故障下交直流***之间的相互影响。 The dynamic equivalent method described above uses the equivalent simplified grid to replace the original grid for electromagnetic transient simulation and real-time simulation research, analyzes the interaction between multiple DCs, and AC and DC systems under DC faults and AC faults near DC drop points. The interaction between each other.

其中，所述动态等值方法选择直流闭锁以及直流落点附近的交流故障作为故障集；基于这些故障扰动，进行同调机群的划分以及***的动态等值，同时也校核等值电网在这些故障扰动下是否具有跟原***相同的动态响应特性。 The dynamic equivalence method selects DC blocking and an AC fault near the DC drop point as a fault set; based on the fault disturbances, performs the division of the coherent cluster and the dynamic equivalent of the system, and also checks the equivalent grid in these faults. Whether it has the same dynamic response characteristics as the original system under disturbance.

其所述动态等值的方法保证等值前后，区内 500kV电网在直流闭锁故障以及直流落点附近交流故障等预想的故障集下具有相近的动态响应特性。 The dynamic equivalence method ensures that the 500kV grid has similar dynamic response characteristics under the expected fault set such as DC blocking fault and AC fault near DC drop point.

其所述的动态响应曲线至少包括发电机的功角变化曲线、母线电压变化曲线以及线路有功功率变化曲线。 The dynamic response curve described therein includes at least a power angle variation curve of the generator, a bus voltage variation curve, and a line active power variation curve.

具体的，在所述区外电网的等值简化步骤中，保留区内电网的所有外部受电通道；保留区外网送至区内网的全部直流线路和送端换流站；保留区外网送至区内网的特高压交流送电线路；保留区外网特高压线路以及相连的变电站和发电厂；区外网低电压网络采用等值负荷与等值发电机的组合进行模拟；区外电网对区内电网扰动的动态响应通过等值的发电机来模拟；区外网的直流送端与区外网等值发电机直接相连；其余区外网络全部简化。 Specifically, in the equivalent simplification step of the external power grid, all external power receiving channels of the power grid in the area are reserved; all the DC lines and the transmitting end converter stations of the reserved area are sent to the regional network; The UHV AC transmission line sent to the regional network; the UHV line in the reserved area and the connected substation and power plant; The low voltage network of the extranet is simulated by the combination of equivalent load and equivalent generator; The dynamic response of the external power grid to the disturbance of the power grid in the area is simulated by the equivalent generator; the DC feed end of the extranet is directly connected to the equivalent generator of the extranet; the rest of the network is simplified.

其中，所述的等值发电机均采取无穷大机组模型。 Wherein, the equivalent generators all adopt an infinite unit model.

其对所述低电压网络进行等值简化，包括对区内电网中 220kV 及以下低电压网络进行等值。 It equates the low voltage network to equivalence, including equalizing the low voltage network of 220kV and below in the regional power grid.

在所述区外电网的等值简化步骤中，采用基于物理等效的等值方法，对于直流落点附近的 220kV 电网，表示为发电机和负荷的组合；对于其它远离直流的 220kV电网等值为负荷；其过程如下：对给定故障集进行短路计算，计算母线残压，初步确定等值模型的区域划分；分别统计区域内接入 220kV及以下网络的发电机组的容量及动能，以及它们占区域内所有发电机组容量和动能的比重，结合残压数据，确定区域 220kV***等值模型；对不同的等值模型，确定模型参数，得到区内简化电网；通过调整区内等值负荷的功率值，使得区内电网简化前后的潮流计算结果一致；再校核动态等值方案的效果，对比相同扰动下等值前后重要的发电机的功角变化曲线、母线电压变化曲线以及线路有功功率变化曲线，观察两者是否接近；最后对简化电网进行适应性分析，评估动态等值方案在其他故障类型、运行方式发生变化以及网架发生变化等情况下的有效性。 In the equivalent simplification step of the out-of-zone power grid, a physical equivalent equivalent method is adopted, which is expressed as a combination of a generator and a load for a 220 kV power grid near the DC drop point; for other 220 kV grids far away from the DC For the load; the process is as follows: short-circuit calculation for a given fault set, calculate the residual voltage of the busbar, and initially determine the regional division of the equivalent model; separately calculate the capacity and kinetic energy of the generator set connected to the network of 220kV and below, and their The proportion of the capacity and kinetic energy of all generator sets in the region, combined Residual pressure data, determine the regional 220kV system equivalent model; determine the model parameters for different equivalence models, and obtain the simplified grid in the area; adjust the power value of the equivalent load in the area to make the power flow calculation results before and after the regional power grid simplification Consistent; check the effect of the dynamic equivalent scheme, compare the power angle curve of the generator before and after the equivalent disturbance, the bus voltage curve and the line active power curve, and observe whether the two are close; Perform an adaptive analysis to assess the effectiveness of dynamic equivalence schemes in other fault types, changes in operating modes, and changes in the grid.

其中，所述等值为负荷的具体步骤如下- Wherein, the specific steps of the equal value are as follows -

10-1、对原网络进行潮流计算，将该 500kV节点所接多台变压器参数按并联方式聚合为一台等值变压器，统计该节点下所有变压器 220kV侧下送功率，累加后作为总负荷接于等值变压器 220kV侧。如有第三绕组（35kV ) ，统计 35kV侧无功补偿情况，累加后接于等值变压器 35kV侧； 10-1. Perform power flow calculation on the original network. The transformer parameters connected to the 500kV node are aggregated into an equivalent transformer in parallel. The power of the 220kV side of all transformers under the node is counted, and the total load is added after the accumulation. On the 220kV side of the equivalent transformer. If there is a third winding (35kV), the reactive power compensation condition of the 35kV side is counted, and the accumulation is connected to the 35kV side of the equivalent transformer;

10-2 , 对等值后进行潮流计算，优化调整 220kV侧等值负荷功率值，保证等值前后***潮流基本一致； 10-2. Perform power flow calculation after equal value, optimize and adjust the 220kV side equivalent load power value, and ensure that the system currents are basically consistent before and after the equivalent value;

10- 3 , 对等值后***进行时域仿真，对比等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑采用负荷加发电机的动态仿真模型。 10- 3. After the equivalence, the system performs time domain simulation, compares the corresponding dynamic simulation curves before and after the equivalence, and calculates the evaluation index. If the requirements are met, the model is adopted. If the requirements are not met, further analysis is performed, and the load is considered. Dynamic simulation model of the generator.

其所述等值为发电机加负荷模型的具体步骤如下- The specific steps of the equivalent load generator model are as follows -

11- 1、发电机容量及等值负荷容量的确定 11- 1. Determination of generator capacity and equivalent load capacity

对原网络进行潮流计算，将该 500kV变电站内接于同一母线的多台变压器参数按并联方式聚合为一台等值变压器，统计该母线所有变压器 220kV 侧下送功率，可得 220kV侧出等值出力为 The power flow calculation is performed on the original network, and the parameters of the plurality of transformers connected to the same busbar in the 500kV substation are aggregated into one equivalent transformer in parallel, and the power of the 220kV side of all the transformers is counted, and the 220kV side output equivalent is obtained. Output is

如有 35kV第三绕组，统计 35kV侧无功补偿情况，累加后接于等值变压器 35kV侧； If there is a 35kV third winding, the reactive power compensation of the 35kV side is counted, and the accumulation is connected to the 35kV side of the equivalent transformer;

统计接入 220kV分区中运行的发电机总容量，所述接入 220kV分区中运行的发电机总容量不包括与 500kV电网直接相连的发电机，累加后得到等值发电机容量，记为 + Statistical access to the total capacity of the generator operating in the 220kV zone. The total capacity of the generator operating in the 220kV zone does not include the generator directly connected to the 500kV grid. After the accumulation, the equivalent generator capacity is obtained, which is recorded as +

计算等值负荷功率为： P_L + jQ_L = (P_∑ + P_G) + j(Q_∑ + Q_G)， Calculate the equivalent load power as: P _L + jQ _L = (P _∑ + P _G ) + j(Q _∑ + Q _G ),

11-2 , 等值发电机的次暂态电抗采用聚合的方式获得，即

式中， _g为该分区内发电机总数， .为第台发电机的额定容量， ^为第台发电机的次暂态电抗。 11-2, the sub-transient reactance of the equivalent generator is obtained by polymerization, that is,

Where _{g is} the total number of generators in the zone, is the rated capacity of the first generator, and ^ is the secondary transient reactance of the first generator.

将此参数转化成以系

Convert this parameter to

发电机升压变的参数根据等值前后母线短路电流保持相同的要求来确定；在等值前网络中，该 500kV母线上三相短路，统计该母线 220kV提供的短路电流 The parameters of the generator boosting change are determined according to the same requirements of the busbar short-circuit current before and after the equivalence; in the network before the equivalence, the three-phase short circuit of the 500kV bus is used, and the short-circuit current provided by the busbar 220kV is counted.

在潮流计算程序 BPA中计算短路，不考虑潮流影响，即 = 1，则有 Calculate the short circuit in the load flow calculation program BPA, regardless of the influence of the flow, ie = 1, then

^{+ X}T S_S) + ¾■■(¾) _ ⁼丄 Ύ ' 即 ^XT2(S_S) _ =丄 7__ ^ΧηιΆ·) _~ ¾■■(¾) ^{+ X} TS _S ) + 3⁄4■■(3⁄4) _ ⁼丄Ύ ' ie ^X T2(S _S ) _ = ^丄 7__ ^Χηι Ά·) _~ 3⁄4■■(3⁄4)

式中， S_B为***基准容量，默认为 100MVA, 进而计算出升压变压器等值电抗 Where, S _B is the system reference capacity, the default is 100MVA, and then the step-up transformer equivalent reactance is calculated.

对于等值发电机转动惯量，采用下式计算 For the moment of inertia of the equivalent generator, the following formula is used

H = Ί + … · ^

H = Ί + ... · ^

式中，^^^^^和^^…^分别为 220kV分区内发电机组的转动惯量和容量，为 220kV分区内发电机组容量之和； Where ^^^^^ and ^^...^ are the moment of inertia and capacity of the generator set in the 220kV zone, respectively, which is the sum of the capacity of the generator set in the 220kV zone;

11-3 , 对等值后进行潮流计算，优化调整 220kV侧等值负荷功率，满足等值前后***潮流基本一致； 11-3. After the equivalent value, the power flow calculation is performed, and the 220kV side equivalent load power is optimized and adjusted, and the system currents are basically consistent before and after the equal value;

11-4、对等值后进行短路计算，优化调整发电机升压变压器电抗，满足等值前后***短路电流基本一致； 11-4. Perform short-circuit calculation after the equivalence value, optimize and adjust the reactance of the generator step-up transformer, and satisfy the equivalent value. The short-circuit current of the system is basically the same;

11-5、对等值后***进行时域仿真，对于等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑对模型进行微调。 11-5. Perform the time domain simulation on the system after the equivalence. Calculate the evaluation index for the corresponding dynamic simulation curve before and after the equivalence. If the requirements are met, use this model. If the requirements are not met, perform further analysis and consider the model. Fine tune.

上述的对模型进行微调，包括弱化励磁***调压能力和调整原动机及调速器调频能力。 The above-mentioned fine-tuning of the model includes weakening the excitation system's voltage regulation capability and adjusting the prime mover and governor frequency modulation capability.

进一步的，在对所述的区内低电压网络进行等值简化时，对预想故障集内的相关母线或线路施加短路故障，抽取部分节点作为代表节点计算其残压，根据代表节点的残压情况，在区内中进一步划分各子区域；对于残压较低的子区域，考虑等值为发电机加负荷；对于残压较高的子区域，先等值为负荷，然后根据等值前后动态特性和直接连入 500kV ***机组的容量和动能比重情况选择是否增大直接连入 500kV***机组的容量和动能，即近似加等值机，使等值后发电机组的整体容量和动能与等值前大致相同。 Further, when the low-voltage network in the region is simplified, a short-circuit fault is applied to the relevant bus or line in the expected fault set, and a part of the node is extracted as a representative node to calculate the residual voltage, according to the residual voltage of the representative node. Situation, further sub-regions are divided in the region; for sub-regions with lower residual pressure, The equivalent value is the generator load; for the sub-area with higher residual pressure, the load is equal to the load, and then according to the dynamic characteristics before and after the equivalent and the capacity and kinetic energy ratio directly connected to the 500kV system unit, whether to increase the direct connection The capacity and kinetic energy of the 500kV system unit is approximately equal to the equal value machine, so that the overall capacity and kinetic energy of the equivalent generator set are approximately the same as before.

其为了确定所述各子区域的具体等值方案，对部分子区域采用发电机加负荷和近似加等值机两种等值方案后所获得的动态特性曲线进行比较分析；若对某子区域两种不同等值方案的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前偏差较大，发电机加负荷的动态特性曲线与等值前拟合程度较好，则对该子区域采用发电机加负荷的等值方案；若对某子区域等值前后的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前的拟合程度就己较好，则不需等值为发电机加负荷。 In order to determine the specific equivalence scheme of the sub-regions, a comparative analysis is made on the dynamic characteristic curves obtained by using the generator load and the approximate plus equalizer scheme for some sub-regions; The dynamic characteristic curves of two different equivalent schemes are compared and analyzed. All the equivalent dynamic load curves of the load have a large deviation from the pre-equal deviation. The dynamic characteristic curve of the generator load is better than the pre-equal degree. The sub-area adopts the equivalent scheme of generator load; if the dynamic characteristic curves of the sub-area before and after the equivalent value are compared and analyzed, all the equivalent values of the dynamic characteristic curve of the load and the equivalent before the equivalence are compared. Well, there is no need to wait for the generator to load.

在对所述区外电网动态等值以及区内电网动态等值之后，均分别对等值效果进行校核。 After the dynamic equivalent of the grid outside the zone and the dynamic equivalent of the grid in the zone, the equivalent effects are checked separately.

所述的对等值效果进行校核，包括进行动态稳定校核。 The checking of the equivalent effect is performed, including performing dynamic stability check.

其所述的动态稳定校核是比较区内电网和等值后的区内电网在相同的故障扰动下，发电机功角、母线电压以及线路有功功率的变化曲线是否接近，变化规律是否相似，以检验动态等值的效果。 The dynamic stability check is compared between the regional power grid and the equivalent regional power grid under the same fault disturbance, whether the generator power angle, the bus voltage and the line active power change curve are close, and the change laws are similar. To test the effect of dynamic equivalence.

在进行所述动态稳定校核时，选取具有代表性的发电机、直流落点附近的 500kV和 lOOOkV母线、 500k V和 1000kV线路等元件；在同一故障扰动下，将等值前后这些元件物理量的变化曲线绘制在一起，比较两条曲线的初始值、稳态值以及仿真时间段内的变化规律是否一致或相近；如果二者相近，表明简化电网与原电网在故障扰动下具有相同的动态响应特性，动态等值效果良好；如果二者差别较大，则需要修改等值方案，重新进行等值。 In the dynamic stability check, select representative generators, 500kV and lOOOk busbars near the DC drop point, 500k V and 1000kV lines, etc.; under the same fault disturbance, the physical quantities of these components will be equivalent before and after The curves are plotted together to compare the initial values of the two curves, the steady-state values, and the changes in the simulation period. If they are similar, it means that the simplified grid and the original grid have the same dynamic response under fault disturbance. The characteristics, dynamic equivalence effect is good; if the difference between the two is large, you need to modify the equivalence scheme and re-equalize the equivalence.

更进一步的，所述的动态等值方法采用相对均方根误差 RMS指标来衡量等值前后***在相同扰动下的动态响应是否一致；所述的相对均方根误差 RMS为等值前后动态曲线各点绝对误差的均方根与等值前曲线各点的均方根的比值，即 Further, the dynamic equivalence method uses the relative root mean square error RMS index to measure whether the dynamic response of the system before and after the equivalent is consistent under the same disturbance; the relative root mean square error RMS is an equivalent before and after dynamic curve The ratio of the root mean square of the absolute error of each point to the root mean square of each point of the contour before the equivalent, ie

计算***等值前后在同一故障下动态曲线的相对均方根误差 RMS，如果其误差在可接受的范围内，则认为其符合要求； Calculate the relative root mean square error RMS of the dynamic curve under the same fault before and after the system equivalent, if it is wrong If the difference is within the acceptable range, it is considered to meet the requirements;

在计算相对均方根误差 RMS时，只选取预想故障下线路有功功率等值前后的动态曲线进行定量分析。与现有技术比较，本发明的优点是- When calculating the relative root mean square error RMS, only the dynamic curve before and after the equivalent active power of the line under the expected fault is selected for quantitative analysis. Compared with the prior art, the advantages of the present invention are -

1. 采用基于经验的动态等值方法对区外电网进行动态等值，采用基于物理等效的动态等值方法对区内电网进行动态等值，根据不同的电网特性，对区外电网以及区内电网应采用不同的动态等值原则和方法，可大大减少； 1. Using the dynamic equivalent method based on experience to dynamically equivalence the extra-regional power grid, using the dynamic equivalent method based on physical equivalents to dynamically equivalate the regional power grid, and according to different grid characteristics, the extra-regional power grid and the district The internal power grid should adopt different dynamic equivalent principles and methods, which can be greatly reduced;

2. 对区外电网以及区内电网分别进行动态等值后，均对等值效果进行评估，直流落点附近母线电压、线路潮流与等值前基本一致，发生直流故障以及直流落点附近交流故障后，动态响应也与等值前基本一致，并且在运行方式以及网架发生变化后，仍具有适应性； 2. After the dynamic equivalent of the external power grid and the regional power grid, the equivalent effect is evaluated. The bus voltage and line current near the DC drop point are basically the same as before the equivalent value. DC faults occur and AC near DC drop occurs. After the fault, the dynamic response is basically the same as before the equivalent, and it is still adaptable after the operation mode and the grid change.

3. 采用相对均方根误差（RMS)来衡量两条曲线之间的拟合程度，可以有效地判别等值前后动态响应曲线的差异，评估动态等值效果。 3. Using the relative root mean square error (RMS) to measure the degree of fit between the two curves, it is possible to effectively discriminate the difference between the dynamic response curves before and after the equivalence and evaluate the dynamic equivalent effect.

4. 简化区内电网在大大简化***的同时，也能获得与原实际电网相近的仿真分析结果，区内简化电网可代替原实际电网进行电磁暂态仿真研究，具有很好的工程实用性。附图概述 4. Simplify the power grid in the area while greatly simplifying the system, and also obtain the simulation analysis results similar to the original actual power grid. The simplified grid in the area can replace the original actual power grid for electromagnetic transient simulation research, which has good engineering practicability. BRIEF abstract

图 1是本发明交直流混联大电网动态等值方法示意图； 1 is a schematic diagram of a dynamic equivalent method of an AC-DC hybrid large power grid according to the present invention;

图 2是本发明交直流混联大电网动态等值步骤方框示意图； 2 is a schematic block diagram of a dynamic equivalent step of an AC-DC hybrid large power grid according to the present invention;

图 3为一种故障集的实例示意图； Figure 3 is a schematic diagram of an example of a fault set;

图 4为发电机的功角变化曲线的实例示意图； Figure 4 is a schematic diagram showing an example of a power angle variation curve of a generator;

图 5为发电机功角摇摆曲线的实例示意图； Figure 5 is a schematic diagram showing an example of a generator power angle rocking curve;

图 6为母线电压变化曲线的实例示意图； Figure 6 is a schematic diagram showing an example of a bus voltage variation curve;

图 7为线路有功功率变化曲线的实例示意图。具体实施方式 Figure 7 is a schematic diagram showing an example of a line active power variation curve. detailed description

下面结合附图对本发明做进一步说明。 The invention will be further described below in conjunction with the accompanying drawings.

图 1中，本发明技术方案中交直流混联大电网动态等值方法的关键思路是对区外电网采用基于经验的动态等值方法，将区外电网用等值发电机来表示，得到区外简化电网；然后采用基于物理等效的动态等值方法，对区内低电压网络进行等值简化，得到最终的区内简化电网。 In Fig. 1, the key idea of the dynamic equivalence method of AC/DC hybrid large power grid in the technical scheme of the present invention is to adopt an empirically based dynamic equivalence method for the extra-regional power grid, and express the external grid with an equivalent generator to obtain The grid is simplified outside the area; then the dynamic equivalent method based on physical equivalent is used to simplify the equivalent of the low-voltage network in the area, and the simplified grid in the final area is obtained.

同时，在区外电网动态等值以及区内电网动态等值之后，均分别对等值效果进行校核，最后通过比较区内简化电网与实际电网在相同故障下的动态响应曲线，校核整个动态等值原则和方法的有效性。 At the same time, after the dynamic equivalent of the grid outside the grid and the dynamic equivalent of the grid in the region, the equivalent effects are checked separately. Finally, the dynamic response curves of the simplified grid and the actual grid under the same fault are compared by comparing the regions, and the entire calibration is checked. The validity of dynamic equivalence principles and methods.

由图可知，整个动态等值过程分为两个阶段进行，采用这种方式的目的，是为了使动态等值方法在工程上具有很好的实用性。 It can be seen from the figure that the whole dynamic equivalent process is divided into two stages. The purpose of this method is to make the dynamic equivalent method have good practicability in engineering.

建立一个大规模电力***的动态等值模型主要是减少***状态变量，降低系统方程的维数，同时保留***的主要特征，根据一定的要求将外部***降阶简化。 The establishment of a dynamic equivalent model of a large-scale power system is mainly to reduce the system state variables, reduce the dimensionality of the system equations, while retaining the main features of the system, and simplifying the reduction of external systems according to certain requirements.

由于动态等值对外部***进行等值简化，使得等值***中的动态元件数目大大减少，所以大大降低了等值***的状态量和微分方程数目。可以用对等值*** 的研究代替对原***的研究，这样既能节省人力和物力，抓住了主要矛盾，在保证必要精度的前提下可以极大地提高***分析计算效率，从而可以有效地对大规模电力***进行机电暂态仿真、电磁暂态仿真以及实时仿真的研究。 Since the dynamic equivalent simplifies the external system, the number of dynamic components in the equivalent system is greatly reduced, so the state quantity and the number of differential equations of the equivalent system are greatly reduced. The research on the original system can be replaced by the research of the equivalent system, which can save manpower and material resources, grasp the main contradictions, and greatly improve the system analysis and calculation efficiency under the premise of ensuring the necessary precision, so that it can effectively Large-scale power systems for electromechanical transient simulation, electromagnetic transient simulation, and real-time simulation.

图 2中，本发明技术方案提供了一种基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态等值方法包括下列步骤- In FIG. 2, the technical solution of the present invention provides a dynamic equivalent method for AC/DC hybrid large power grid based on engineering application, characterized in that the dynamic equivalence method comprises the following steps -

1-3、对区外电网采用基于经验的动态等值方法，将区外电网用等值发电机来表示，得到区外简化电网； 1-3. Using an empirically-based dynamic equivalent method for the external power grid, the external grid is represented by an equivalent generator, and the grid is simplified outside the district;

1-4、采用基于物理等效的动态等值方法，对区内低电压网络进行等值简化，得到最终的区内简化电网； 1-4. Using the dynamic equivalence method based on physical equivalent, the equivalent value of the low-voltage network in the area is simplified, and the simplified power grid in the final area is obtained;

在本发明技术方案中，用等值简化电网代替原电网进行电磁暂态仿真和实时仿真研究，分析多回直流之间的相互影响，以及直流故障和直流落点附近交流故障下交直流***之间的相互影响。其中，上述的动态等值方法选择直流闭锁以及直流落点附近的交流故障作为故障集；基于这些故障扰动，进行同调机群的划分以及***的动态等值，同时也校核等值电网在这些故障扰动下是否具有跟原***相同的动态响应特性。 In the technical solution of the present invention, the electromagnetic transient simulation and real-time simulation research are carried out by using the equivalent simplified power grid instead of the original power grid, and the mutual influence between the multiple DCs and the DC fault and the AC fault near the DC drop point are analyzed. The mutual influence. The dynamic equivalent method described above selects DC blocking and AC faults near the DC drop point as a fault set; based on these fault disturbances, performs the division of the coherent group and the dynamic equivalent of the system, and also checks the equivalent grid in these faults. Whether it has the same dynamic response characteristics as the original system under disturbance.

一般来说，施加扰动的预想故障集（简称为是事故集）应根据等值后简化电网的仿真用途进行合理地选择。本技术方案中，动态等值的目的是将区外电网以及区内电网内部的低电压网络进行简化，用等值简化电网代替原电网进行电磁暂态仿真和实时仿真研究，分析多回直流之间的相互影响，以及直流故障和交流故障下交直流***之间的相互影响。因此可以选择直流闭锁以及直流落点附近的交流故障作为预想故障集。基于这些故障扰动，进行同调机群的划分以及***的动态等值，同时也校核等值电网在这些故障扰动下是否具有跟原***相同的动态响应特性。 In general, the expected set of faults to which the disturbance is applied (referred to as the set of accidents) should be reasonably selected based on the simulated use of the simplified grid after the equivalent. In this technical solution, the purpose of the dynamic equivalence is to simplify the low-voltage network inside the regional power grid and the regional power grid, and use the equivalent value to simplify the grid to replace the original power grid for electromagnetic transient simulation and real-time simulation research, and analyze multiple DCs. The interaction between the two, and the interaction between the AC and DC systems under DC faults and AC faults. Therefore, DC blocking and AC faults near the DC drop point can be selected as the expected fault set. Based on these fault disturbances, the division of the coherent clusters and the dynamic equivalence of the system are performed, and the equivalent grid is also checked for the same dynamic response characteristics as the original system under these fault disturbances.

一个典型的预想故障集如图 3所示，由于故障集在动态仿真和电网分析中为现有技术，故其构成含义和具体用途在此不再叙述。 A typical expected fault set is shown in Figure 3. Since the fault set is prior art in dynamic simulation and grid analysis, its meaning and specific use are not described here.

典型的发电机功角变化曲线、发电机功角摇摆曲线、母线电压变化曲线以及线路有功功率变化曲线的实例示意图如图 4至图 7所示，由于这些图均为按照现有技术标准和采用标准仪器进行测试所得到的，故其各条曲线及其波形所包含的含义在此不再叙述。 A typical schematic diagram of the generator power angle variation curve, the generator power angle rocking curve, the bus voltage voltage curve, and the line active power curve is shown in Figures 4 to 7, since these figures are in accordance with the prior art standards and adopted. Standard instruments are tested, so the meanings of the various curves and their waveforms are not described here.

进一步的，在所述区外电网的等值简化步骤中，采用基于物理等效的等值方法，对于直流落点附近的 220kV电网，表示为发电机和负荷的组合；对于其它远离直流的 220kV电网等值为负荷；其过程如下- 对给定故障集进行短路计算，计算母线残压，初步确定等值模型的区域划分；分别统计区域内接入 220kV及以下网络的发电机组的容量及动能，以及它们占区域内所有发电机组容量和动能的比重，结合残压数据，确定区域 220kV***等值模型；对不同的等值模型，确定模型参数，得到区内简化电网；通过调整区内等值负荷的功率值，使得区内电网简化前后的潮流计算结果一致；再校核动态等值方案的效果，对比相同扰动下等值前后重要的发电机的功角变化曲线、母线电压变化曲线以及线路有功功率变化曲线，观察两者是否接近；最后对简化电网进行适应性分析，评估动态等值方案在其他故障类型、运行方式发生变化以及网架发生变化等情况下的有效性。 Further, in the equivalent simplification step of the external power grid, the equivalent equivalent based on physical equivalent is adopted. Method, for the 220kV grid near the DC drop point, expressed as the combination of generator and load; for other 220kV grids far away from DC, the load is equivalent; the process is as follows - short-circuit calculation for a given fault set, calculate the bus residual voltage, Initially determine the regional division of the equivalence model; separately calculate the capacity and kinetic energy of the generator sets connected to the network of 220kV and below, and their proportions of the capacity and kinetic energy of all generator sets in the area, combined with the residual pressure data, determine the regional 220kV system Equivalence model; For different equivalence models, determine the model parameters, and obtain the simplified grid in the zone; By adjusting the power value of the equivalent load in the zone, the power flow calculation results before and after the simplification of the regional power grid are consistent; The effect of the scheme is to compare the power angle variation curve, the bus voltage curve and the line active power curve of the generators that are important before and after the same disturbance, and observe whether the two are close to each other. Finally, the adaptive analysis of the simplified grid, evaluation of dynamics, etc. The value scheme changes in other fault types, modes of operation, and Effectiveness in the case of aircraft and other changes.

其中， A、所述等值为负荷的具体步骤如下- Among them, A, the specific steps of the load is as follows -

Al、对原网络进行潮流计算，将该 500kV节点所接多台变压器参数按并联方式聚合为一台等值变压器，统计该节点下所有变压器 220kV侧下送功率，累加后作为总负荷接于等值变压器 220kV侧。如有第三绕组（35kV) ，统计 35kV 侧无功补偿情况，累加后接于等值变压器 35kV侧； Al. Perform power flow calculation on the original network. The transformer parameters connected to the 500kV node are aggregated into an equivalent transformer in parallel. The power of the 220kV side of all transformers under the node is counted, and the total load is added after the accumulation. Value transformer 220kV side. If there is a third winding (35kV), the reactive power compensation of the 35kV side is counted, and the accumulation is connected to the 35kV side of the equivalent transformer;

A2, 对等值后进行潮流计算，优化调整 220kV侧等值负荷功率值，保证等值前后***潮流基本一致； A2, after the equivalent value, calculate the power flow, optimize and adjust the 220kV side equivalent load power value, and ensure that the system currents before and after the equivalent are basically consistent;

A3、对等值后***进行时域仿真，对比等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑采用负荷加发电机的动态仿真模型。 A3. After the equivalence, the system performs time domain simulation, compares the corresponding dynamic simulation curves before and after the equivalence, and calculates the evaluation index. If the requirements are met, the model is adopted. If the requirements are not met, further analysis is performed, and the load plus generator is considered. Dynamic simulation model.

B、其所述等值为发电机加负荷模型的具体步骤如下- B. The specific steps of the equivalent load generator model are as follows -

Bl、发电机容量及等值负荷容量的确定 Bl, determination of generator capacity and equivalent load capacity

对原网络进行潮流计算，将该 500kV变电站内接于同一母线的多台变压器参数按并联方式聚合为一台等值变压器，统计该母线所有变压器 220kV侧下送功率，可得 220kV侧出等值出力为 The power flow calculation is performed on the original network, and the parameters of the plurality of transformers connected to the same busbar in the 500kV substation are aggregated into one equivalent transformer in parallel, and the power of the 220kV side of all the transformers is counted, and the 220kV side output equivalent value can be obtained. Output is

如有 35kV第三绕组，统计 35kV侧无功补偿情况，累加后接于等值变压器 35kV侧； If there is a 35kV third winding, the reactive power compensation of the 35kV side is counted, and the cumulative voltage is connected to the 35kV side of the equivalent transformer;

统计接入 220kV分区中运行的发电机总容量，所述接入 220kV分区中运行的发电机总容量不包括与 500kV电网直接相连的发电机，累加后得到等值发电机容量，记为计算等值负荷功率为： P_L+ jQ_L = (P_∑ + P_G) + j(Q_∑ + Q_G)， Calculate the total capacity of the generators operating in the 220kV zone. The total capacity of the generators operating in the 220kV zone does not include the generators directly connected to the 500kV grid. After the accumulation, the equivalent generator capacity is obtained. Calculate the equivalent load power as: P _L + jQ _L = (P _∑ + P _G ) + j(Q _∑ + Q _G ),

B2、等值发电机的次暂态电抗采用聚合的方式获得，即

式中， _g为该分区内发电机总数， .为第台发电机的额定容量， 4为第台发电机的次暂态电抗。 B2, the sub-transient reactance of the equivalent generator is obtained by polymerization, ie

Where _{g is} the total number of generators in the zone, is the rated capacity of the first generator, and 4 is the secondary transient reactance of the first generator.

将此参数转化成以***基

发电机升压变的参数根据等值前后母线短路电流保持相同的要求来确定；在等值前网络中，该 500kV母线上三相短路，统计该母线 220kV提供的短路电流 Convert this parameter to a system basis

The parameters of the generator boosting change are determined according to the same requirements of the busbar short-circuit current before and after the equivalence; in the network before the equivalence, the three-phase short circuit of the 500kV bus is used, and the short-circuit current provided by the busbar 220kV is counted.

在潮流计算程序 BPA中计算短路，不考虑潮流影响，即 =1，则有 Calculate the short circuit in the power flow calculation program BPA, regardless of the influence of the power flow, ie =1, then

.. _丄 _ρπ _丄_ _ ■■ 式中， S_B为***基准容量，默认为 100MVA, 进而计算出升压变压器等值 .. _ _丄ρπ _ _丄 _ _ ■■ where S _B is the system reference capacity, the default is 100MVA, and then the step-up transformer equivalent is calculated

对于等值发电机转动惯量，采用下式计算 s B S_B S_g S_G For the moment of inertia of the equivalent generator, calculate s BS _B S _g S _G using the following formula

=_Η! · +Η₂ ·^+ … +_Hs , ^L (2-3) 式中， H₁ H₂，...H^D 分别为 220kV分区内发电机组的转动惯量和容量，为 220kV分区内发电机组容量之和； = _Η! · +Η ₂ ·^+ ... + _Hs , ^L (2-3) where H ₁ H ₂ ,...H^D are the moment of inertia and capacity of the generator set in the 220kV zone, respectively, 220kV The sum of the capacity of the generating units in the sub-area;

B3, 对等值后进行潮流计算，优化调整 220kV 侧等值负荷功率，满足等值前后***潮流基本一致； B3, after the equivalent value, the power flow calculation is performed, and the equivalent load power of the 220kV side is optimized and adjusted, and the system currents are basically consistent before and after the equal value;

B4、对等值后进行短路计算，优化调整发电机升压变压器电抗，满足等值前后***短路电流基本一致； B4. Perform short-circuit calculation after the equivalence value, optimize and adjust the reactance of the generator step-up transformer, and satisfy the equivalent value. The short-circuit current of the system is basically the same;

B5、对等值后***进行时域仿真，对于等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑对模型进行微调。上述的对模型进行微调，包括弱化励磁***调压能力和调整原动机及调速器调频能力。 B5. Perform time domain simulation on the system after equal value. Calculate the evaluation index for the corresponding dynamic simulation curve before and after the equivalence. If the requirements are met, use this model. If the requirements are not met, perform further analysis and consider fine-tuning the model. The above-mentioned fine-tuning of the model includes weakening the excitation capacity of the excitation system and adjusting the prime mover and the governor's frequency modulation capability.

进一步的，在对所述的区内低电压网络进行等值简化时，对预想故障集内的相关母线或线路施加短路故障，抽取部分节点作为代表节点计算其残压，根据代表节点的残压情况，在区内中进一步划分各子区域；对于残压较低的子区域，考虑等值为发电机加负荷；对于残压较高的子区域，先等值为负荷，然后根据等值前后动态特性和直接连入 500kV ***机组的容量和动能比重情况选择是否增大直接连入 500kV***机组的容量和动能，即近似加等值机，使等值后发电机组的整体容量和动能与等值前大致相同。 Further, when the low-voltage network in the region is simplified, a short-circuit fault is applied to the relevant bus or line in the expected fault set, and a part of the node is extracted as a representative node to calculate the residual voltage, according to the residual voltage of the representative node. In the case, further sub-areas are divided in the zone; for sub-regions with lower residual pressure, consider equal value for generator load; for sub-regions with higher residual pressure, first equal load, then according to equivalent The dynamic characteristics and the capacity and kinetic energy proportion of the unit directly connected to the 500kV system are selected to increase the capacity and kinetic energy of the unit directly connected to the 500kV system, that is, the equivalent equalizer is added to make the overall capacity and kinetic energy of the equivalent generator set and so on. The values are roughly the same before.

为了确定所述各子区域的具体等值方案，对部分子区域采用发电机加负荷和近似加等值机两种等值方案后所获得的动态特性曲线进行比较分析；若对某子区域两种不同等值方案的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前偏差较大，发电机加负荷的动态特性曲线与等值前拟合程度较好，则对该子区域采用发电机加负荷的等值方案；若对某子区域等值前后的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前的拟合程度就己较好，则不需等值为发电机加负荷。 In order to determine the specific equivalent scheme of each sub-area, the dynamic characteristic curves obtained by using the generator load and the approximate plus equalizer are compared and analyzed for some sub-areas; The dynamic characteristic curves of different equivalence schemes are compared and analyzed. All the equivalent dynamic load curves of the load have a large deviation from the pre-equal deviation. The dynamic characteristic curve of the generator plus load has a good degree of fitting before the equivalence, then The sub-area adopts the equivalent scheme of generator and load; if the dynamic characteristic curves of the sub-area before and after the equivalent value are compared and analyzed, all the equivalent values of the dynamic characteristic curve of the load and the pre-equality degree are better. , there is no need to wait for the generator to load.

在图 4至图 7中，给出了某子区域等值前后的动态特性曲线，图中的实 /粗线为某子区域等值前的实际动态特性曲线，图中的虚 /细线为某子区域等值后的动态特性曲线。与前述理由相同，在此不再对图中曲线构成和波形进行叙述。 In Fig. 4 to Fig. 7, the dynamic characteristic curves before and after the equivalence of a sub-area are given. The real/thick line in the figure is the actual dynamic characteristic curve before the equivalence of a sub-area. The virtual/thin line in the figure is The dynamic characteristic curve after a sub-area is equivalent. For the same reason as described above, the curve configuration and waveforms in the drawings will not be described here.

由上述附图可知，在故障情况下，区内简化电网仍具有与原电网相近的动态响应特性，故区内简化电网保留了原电网的主要动态特性，满足等值原则要求和实际工程仿真研究的需要。 It can be seen from the above figures that in the case of faults, the simplified grid in the zone still has dynamic response characteristics similar to those of the original grid, so the simplified grid retains the main dynamic characteristics of the original grid, meets the requirements of the principle of equivalence and the actual engineering simulation study. Need.

经过上述的简化后，与原有实际电网相比，区内简化电网规模大大缩小，节点数缩小至原来的 4.4%，发电机、线路、变压器等元件数也显著减少，发电机数减少至原来的 9.7%，线路数减少至原来的 4.7%，变压器数减少至原来的 4%。因此对原有实际电网进行动态等值，能大幅降低***规模。 After the above simplification, compared with the original actual power grid, the scale of the simplified power grid in the area is greatly reduced, the number of nodes is reduced to 4.4%, and the number of components such as generators, lines, transformers, etc. is also significantly reduced, and the number of generators is reduced to the original. 9.7%, the number of lines was reduced to 4.7%, and the number of transformers was reduced to 4%. Therefore, dynamic equivalent of the original actual power grid can greatly reduce the system scale.

在分别校核了区外电网动态等值和区内电网动态等值效果的基础上，比较原有实际电网以及区内简化电网的潮流以及动态响应特性，以评估动态等值的综合效果。 On the basis of checking the dynamic equivalent of the extra-region power grid and the dynamic equivalent effect of the regional power grid, the actual power grid and the simplified power grid's power flow and dynamic response characteristics are compared to evaluate the dynamic equivalent.

一、静态潮流比对- 对比等值前后保留线路的有功功率以及母线电压，如果其误差在可接受的范围内，则说明静态潮流等值效果很好，等值前后稳定计算初值的误差较小。 I. Static tidal comparison - compare the active power of the line and the bus voltage before and after the equivalent, if the error is in an acceptable range Within the circumference, it is shown that the static tidal current equivalent effect is very good, and the error of the initial value of the stable calculation before and after the equivalent value is small.

通过比较原有实际电网以及区内简化电网的特高压网架潮流图可知，等值前后保留母线电压水平、保留特高压以及 500kV主网潮流分布基本一致。 By comparing the original actual power grid and the UHV grid power flow diagram of the simplified grid in the area, it can be seen that the pre-reserved bus voltage level, the reserved UHV and the 500kV main network flow distribution are basically the same.

二、动态稳定校核： Second, dynamic stability check:

将原有实际电网以及区内简化电网在同一故障下的动态响应曲线进行比较，包括直流落点附近母线电压变化曲线以及线路有功功率变化曲线，由图 4至 7所示的曲线图可以看出，等值前后***具有相近的动态响应特性，区内简化电网保留了原有实际电网的主要动态特性，满足等值原则要求和实际工程仿真研究的需要。 Comparing the original actual power grid and the dynamic response curve of the simplified grid in the same area under the same fault, including the bus voltage curve near the DC drop point and the line active power curve, which can be seen from the graphs shown in Figures 4 to 7. The system before and after equivalence has similar dynamic response characteristics. The simplified grid in the region retains the main dynamic characteristics of the original actual grid, meeting the requirements of the principle of equivalence and the needs of actual engineering simulation research.

由图 4至图 7可知，直流落点附近母线电压、线路潮流与等值前基本一致，发生直流故障以及直流落点附近交流故障后，动态响应也与等值前基本一致，并且在运行方式以及网架发生变化后，仍具有适应性。此外，在对所述区外电网动态等值以及区内电网动态等值之后，均应分别对等值效果进行校核。 It can be seen from Fig. 4 to Fig. 7 that the bus voltage and the line current near the DC drop point are basically the same as before the equivalent value. After the DC fault occurs and the AC fault near the DC drop point, the dynamic response is basically the same as before the equivalent value, and the operation mode is And after the grid has changed, it is still adaptable. In addition, after the dynamic equivalent of the grid outside the zone and the dynamic equivalent of the grid in the zone, the equivalent effect should be checked separately.

所述的对等值效果进行校核，包括进行动态稳定校核。其所述的动态稳定校核是比较区内电网和等值后的区内电网在相同的故障扰动下，发电机功角、母线电压以及线路有功功率的变化曲线是否接近，变化规律是否相似，以检验动态等值的效果。 The checking of the equivalent effect is performed, including performing dynamic stability check. The dynamic stability check is compared between the regional power grid and the equivalent regional power grid under the same fault disturbance, whether the generator power angle, the bus voltage and the line active power change curve are close, and the change laws are similar. To test the effect of dynamic equivalence.

具体的，在进行所述动态稳定校核时，选取具有代表性的发电机、直流落点附近的 500kV和 1000kV母线、 500kV和 1000kV线路等元件；在同一故障扰动下，将等值前后这些元件物理量的变化曲线绘制在一起，比较两条曲线的初始值、稳态值以及仿真时间段内的变化规律是否一致或相近；如果二者相近，表明简化电网与原电网在故障扰动下具有相同的动态响应特性，动态等值效果良好；如果二者差别较大，则需要修改等值方案，重新进行等值。 Specifically, when performing the dynamic stability check, select a representative generator, 500kV and 1000kV busbars near the DC drop point, 500kV and 1000kV lines, etc.; under the same fault disturbance, the components will be equivalent before and after The physical quantity change curves are drawn together to compare the initial values of the two curves, the steady-state values, and the variation laws within the simulation time period. If the two are similar, it means that the simplified grid and the original grid have the same under fault disturbance. Dynamic response characteristics, dynamic equivalent effect is good; if the difference between the two is large, you need to modify the equivalent scheme and re-equalize the value.

更进一步的，所述的动态等值方法采用相对均方根误差 RMS指标来衡量等值前后***在相同扰动下的动态响应是否一致；所述的相对均方根误差 RMS为等值前后动态曲线各点绝对误差的均方根与等值前曲线各点的均方根的比值，即

Further, the dynamic equivalence method uses the relative root mean square error RMS index to measure whether the dynamic response of the system before and after the equivalent is consistent under the same disturbance; the relative root mean square error RMS is an equivalent before and after dynamic curve The ratio of the root mean square of the absolute error of each point to the root mean square of each point of the contour before the equivalent, ie

计算***等值前后在同一故障下动态曲线的相对均方根误差 RMS，如果其误差在可接受的范围内，则认为其符合要求； Calculate the relative root mean square error RMS of the dynamic curve under the same fault before and after the equivalent of the system, and if the error is within the acceptable range, it is considered to meet the requirements;

在计算相对均方根误差 RMS时，只选取预想故障下线路有功功率等值前后的动态曲线进行定量分析。 When calculating the relative root mean square error RMS, only the dynamic curve before and after the equivalent active power of the line under the expected fault is selected for quantitative analysis.

一个实际的相对均方根误差 RMS计算结果如下所示- An actual relative root mean square error RMS calculation result is as follows -

可见，故障点附近线路有功功率变化曲线的 RMS值均较小，表明曲线拟合较好，进一步定量地表明了等值前后***在这些扰动下具有相近的动态响应。以上的各实施例仅仅是用来解释和说明本发明的，而并非用作对本发明技术方案的限定；本领域的普通技术人员应当认识到，只要在本发明的实质精神范围内，对以上实施例的变化、变形，都将落在本发明权利要求所要求的保护范围内。工业应用性

It can be seen that the RMS value of the active power curve of the line near the fault point is small, indicating that the curve fits well, and further quantitatively shows that the system has similar dynamic response under these disturbances before and after the equivalent. The above embodiments are only intended to explain and explain the present invention, and are not intended to limit the technical solutions of the present invention; those skilled in the art will recognize that the above implementations are within the spirit of the present invention. Variations and modifications of the examples will fall within the scope of protection claimed in the claims of the present invention. Industrial applicability

本发明所提供的基于工程应用的交直流混联大电网的动态等值方法，其技术方案对区外电网和区内低压***进行等值简化，大大降低了等值***的状态量和微分方程数目，用对等值***的研究代替对原***的研究，既能节省人力和物力，抓住了主要矛盾，在保证必要精度的前提下可以极大地提高***分析计算效率，从而可以有效地对大规模电力***进行机电暂态仿真、电磁暂态仿真以及实时仿真的研究。 The dynamic equivalence method of the AC/DC hybrid large power grid based on engineering application provided by the invention has the technical solution to simplify the equivalence of the extra-regional power grid and the low-voltage system in the region, and greatly reduces the state quantity and differential equation of the equivalence system. The number, using the equivalent system research instead of the original system research, can save manpower and material resources, seize the main contradiction, can greatly improve the system analysis and calculation efficiency under the premise of ensuring the necessary accuracy, so that it can effectively Large-scale power systems for electromechanical transient simulation, electromagnetic transient simulation, and real-time simulation.

对实际电网进行区外电网动态等值以及区内电网动态等值后，得到区内简化电网。在区内简化电网中，直流落点附近母线电压、线路潮流与实际基本一致，发生直流故障以及直流落点附近交流故障后，动态响应也与实际电网基本一致，并计算等值前后动态响应曲线的 RMS值，进一步说明了等值前后***在这些扰动下具有相近的动态响应。简化电网在大大简化***的同时，也能获得与原实际电网相近的仿真分析结果，区内简化电网可代替原有实际电网进行电磁暂态仿真研究，具有很好的工程实用性。本发明可广泛用于混联大电网的分析、计算以及电网的调度、管理领域。 After the actual grid is dynamically equivalent to the grid outside the grid and the grid is dynamically equivalent, the simplified grid is obtained in the zone. In the simplified grid in the area, the bus voltage and line current near the DC drop point are basically the same as the actual situation. After DC fault and AC fault near DC drop point, the dynamic response is basically the same as the actual grid, and the RMS value of the dynamic response curve before and after the equivalent value is calculated, which further indicates that the system has similar dynamic response under these disturbances before and after the equivalent. Simplifying the power grid greatly simplifies the system, and can also obtain the simulation analysis results similar to the original actual power grid. The simplified grid can replace the original actual power grid for electromagnetic transient simulation research, which has good engineering practicability. The invention can be widely used in the analysis and calculation of mixed large power grids and in the field of power grid dispatching and management.

Claims

权利要求书 Claim

1. 一种基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态等值方法包括下列步骤-A dynamic equivalence method for AC/DC hybrid large power grid based on engineering application, characterized in that the dynamic equivalence method comprises the following steps -

2. 按照权利要求 1 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态等值方法用等值简化电网代替原电网进行电磁暂态仿真和实时仿真研究，分析多回直流之间的相互影响，以及直流故障和直流落点附近交流故障下交直流***之间的相互影响。 2. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 1, wherein the dynamic equivalent method uses an equivalent simplified grid to replace the original grid for electromagnetic transient simulation and real-time Simulation studies analyze the interaction between multiple DCs and the interaction between DC faults and AC and DC systems under AC faults near DC drop.

3. 按照权利要求 1 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述动态等值方法选择直流闭锁以及直流落点附近的交流故障作为故障集；基于这些故障扰动，进行同调机群的划分以及***的动态等值，同时也校核等值电网在这些故障扰动下是否具有跟原***相同的动态响应特性。 3. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 1, wherein the dynamic equivalence method selects DC blocking and an AC fault near a DC drop point as a fault set; These fault disturbances, the division of coherent clusters and the dynamic equivalent of the system, also check whether the equivalent grid has the same dynamic response characteristics as the original system under these fault disturbances.

4. 按照权利要求 1或 3所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述动态等值的方法保证等值前后，区内 500kV电网在直流闭锁故障以及直流落点附近交流故障等预想的故障集下具有相近的动态响应特性。 4. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 1 or 3, wherein the dynamic equivalence method ensures that the 500 kV power grid is in a DC blocking fault before and after the equivalence. And the expected dynamic response characteristics under the expected fault set such as the AC fault near the DC drop point.

5. 按照权利要求 1 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态响应曲线至少包括发电机的功角变化曲线、母线电压变化曲线以及线路有功功率变化曲线。 5. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 1, wherein the dynamic response curve comprises at least a power angle variation curve of the generator, a bus voltage variation curve, and a line. Active power curve.

6. 按照权利要求 1 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是在所述区外电网的等值简化步骤中， 6. The dynamic equivalence square of an AC/DC hybrid large power grid based on engineering application according to claim 1 Method, characterized in that in the equivalent simplification step of the out-of-zone power grid,

保留区内电网的所有外部受电通道； Retain all external power receiving channels of the power grid in the area;

保留区外网送至区内网的全部直流线路和送端换流站； All the DC lines and the transmitting end converter stations of the reserved area are sent to the regional network;

保留区外网送至区内网的特高压交流送电线路； An extra-high voltage AC transmission line sent to the regional network by the external network of the reserved area;

保留区外网特高压线路以及相连的变电站和发电厂； Retaining extra-high voltage lines outside the area and connected substations and power plants;

区外网低电压网络采用等值负荷与等值发电机的组合进行模拟；区外电网对区内电网扰动的动态响应通过等值的发电机来模拟；区外网的直流送端与区外网等值发电机直接相连； The low-voltage network of the extranet is simulated by the combination of equivalent load and equivalent generator; the dynamic response of the external grid to the disturbance of the grid in the area is simulated by the equivalent generator; the DC transmission of the extranet and the outside of the area Network equivalent generators are directly connected;

其余区外网络全部简化。 The rest of the network outside the area is simplified.

7. 按照权利要求 6 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的等值发电机均采取无穷大机组模型。 7. The dynamic equivalent method of an AC/DC hybrid large power grid based on engineering application according to claim 6, wherein the equivalent generators adopt an infinite unit model.

8. 按照权利要求 1 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是对所述低电压网络进行等值简化，包括对区内电网中 220kV 及以下低电压网络进行等值。 8. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 1, characterized in that the low voltage network is equivalently simplified, including a low voltage of 220 kV and below in the regional power grid. The network is equivalent.

9. 按照权利要求 6 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是在所述区外电网的等值简化步骤中，采用基于物理等效的等值方法，对于直流落点附近的 220kV电网，表示为发电机和负荷的组合；对于其它远离直流的 220kV电网等值为负荷；其过程如下- 对给定故障集进行短路计算，计算母线残压，初步确定等值模型的区域划分； 9. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 6, wherein in the equivalent simplification step of the external power grid, a physical equivalent equivalent method is adopted. For the 220kV grid near the DC drop point, it is expressed as the combination of generator and load; for other 220kV grids far away from DC, the load is equivalent; the process is as follows - short-circuit calculation for a given fault set, calculate the residual voltage of the bus, preliminary Determining the regional division of the equivalence model;

分别统计区域内接入 220kV及以下网络的发电机组的容量及动能，以及它们占区域内所有发电机组容量和动能的比重，结合残压数据，确定区域 220kV系统等值模型； Separate the capacity and kinetic energy of the generator sets connected to the network of 220kV and below in the area, and their proportion of the capacity and kinetic energy of all generator sets in the area, and determine the regional 220kV system equivalent model based on the residual pressure data;

对不同的等值模型，确定模型参数，得到区内简化电网； For different equivalence models, determine the model parameters and obtain a simplified grid in the zone;

通过调整区内等值负荷的功率值，使得区内电网简化前后的潮流计算结果一致； By adjusting the power value of the equivalent load in the zone, the power flow calculation results before and after the simplification of the regional power grid are consistent;

再校核动态等值方案的效果，对比相同扰动下等值前后重要的发电机的功角变化曲线、母线电压变化曲线以及线路有功功率变化曲线，观察两者是否接近；最后对简化电网进行适应性分析，评估动态等值方案在其他故障类型、运行方式发生变化以及网架发生变化等情况下的有效性。 Then check the effect of the dynamic equivalent scheme, compare the power angle curve, the bus voltage curve and the line active power curve of the generators before and after the same disturbance under the same disturbance, and observe whether the two are close to each other. Finally, adapt the simplified grid. Sexual analysis, assessing the effectiveness of dynamic equivalence schemes in the event of other types of failures, changes in operating modes, and changes in the grid.

10. 按照权利要求 6所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述等值为负荷的具体步骤如下-10. The dynamic equivalence square of an AC/DC hybrid large power grid based on engineering application according to claim 6. Method, characterized in that the specific steps of the equal value are as follows -

10-1、对原网络进行潮流计算，将该 500kV节点所接多台变压器参数按并联方式聚合为一台等值变压器，统计该节点下所有变压器 220kV侧下送功率，累加后作为总负荷接于等值变压器 220kV侧。如有第三绕组（35kV )，统计 35kV 侧无功补偿情况，累加后接于等值变压器 35kV侧； 10-1. Perform power flow calculation on the original network. The transformer parameters connected to the 500kV node are aggregated into an equivalent transformer in parallel. The power of the 220kV side of all transformers under the node is counted, and the total load is added after the accumulation. On the 220kV side of the equivalent transformer. If there is a third winding (35kV), the reactive power compensation situation of the 35kV side is counted, and then accumulated and connected to the 35kV side of the equivalent transformer;

10-2 , 对等值后进行潮流计算，优化调整 220kV侧等值负荷功率值，保证等值前后***潮流基本一致； 10-2. Perform power flow calculation after the equal value, optimize and adjust the 220kV side equivalent load power value, and ensure that the system currents are basically consistent before and after the equivalent value;

10- 3、对等值后***进行时域仿真，对比等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑采用负荷加发电机的动态仿真模型。 10- 3, after the equivalent value, the system performs time domain simulation, compares the corresponding dynamic simulation curves before and after the equivalent value, and calculates the evaluation index. If the requirements are met, the model is adopted; if the requirements are not met, further analysis is carried out, and the load is considered. Dynamic simulation model of the generator.

11. 按照权利要求 6所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述等值为发电机加负荷模型的具体步骤如下- 11. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 6, wherein the specific steps of the generator load loading model are as follows -

1 1- 1、发电机容量及等值负荷容量的确定 1 1- 1. Determination of generator capacity and equivalent load capacity

对原网络进行潮流计算，将该 500kV变电站内接于同一母线的多台变压器参数按并联方式聚合为一台等值变压器，统计该母线所有变压器 220kV侧下送功率，可得 220kV侧出等值出力为 _Σ +_ ρ_{∑ ;} The power flow calculation is performed on the original network, and the parameters of the plurality of transformers connected to the same busbar in the 500kV substation are aggregated into one equivalent transformer in parallel, and the power of the 220kV side of all the transformers is counted, and the 220kV side output equivalent value can be obtained. The output is _Σ +_ ρ _{∑ ;}

统计接入 220kV分区中运行的发电机总容量，所述接入 220kV分区中运行的发电机总容量不包括与 500kV电网直接相连的发电机，累加后得到等值发电机容量，记为 The total capacity of the generators operating in the 220kV zone is statistically connected. The total capacity of the generators operating in the 220kV zone does not include the generators directly connected to the 500kV grid. After accumulating, the equivalent generator capacity is obtained.

11-2、等值发电机的次暂态电抗采用聚合的方式获得，即

式中， _g为该分区内发电机总数， .为第台发电机的额定容量， .为第台发电机的次暂态电抗。 11-2. The sub-transient reactance of the equivalent generator is obtained by polymerization, that is,

Where _{g is} the total number of generators in the zone, and is the rated capacity of the first generator, which is the secondary transient reactance of the first generator.

将此参数转化成以***基准容量为参考的标值，即 ¾¾) = ^Xd s. 发电机升压变的参数根据等值前后母线短路电流保持相同的要求来确定； Convert this parameter to a reference value based on the system's baseline capacity, ie 3⁄43⁄4) = ^X d s. The parameters of the generator boost change are determined according to the same requirements for the bus short-circuit current before and after the equivalence;

在等值前网络中，该 500kV母线上三相短路，统计该母线 220kV提供的短路电流 In the network before the equivalence, the three-phase short circuit of the 500kV bus is used, and the short circuit current provided by the bus 220kV is counted.

^XT\{S_S) + ^XT S_S) + ^Xd■■{S_s) _ ⁼丄 ~ ' 即 ^XT'2(S_S) _ ⁼丄~ _~ ^XT\{S_S) _~ ^Xd■■{S_s) ^X T\{S _S ) + ^X TS _S ) + ^X d■■{S _s ) _ ⁼丄~ ' ie ^X T'2(S _S ) _ ⁼丄~ _~ ^X T\{S _S ) _~ ^X d■■{S _s )

式中， S_B为***基准容量，默认为 100MVA, 进而计算出升压变压器等值电抗； Where, S _B is the system reference capacity, the default is 100MVA, and then the equivalent transformer of the step-up transformer is calculated;

=_Ηι · +Η₂ · ^ + ... +_Hll , hL (2-3 ) 式中，^^^^^和^^…^分别为 220kV分区内发电机组的转动惯量和容量，为 220kV分区内发电机组容量之和； = _Ηι · +Η ₂ · ^ + ... + _Hll , hL (2-3 ) where ^^^^^ and ^^...^ are respectively the moment of inertia and capacity of the generator set in the 220kV zone, which is 220kV partition The sum of the capacity of the internal generator set;

11-3 , 对等值后进行潮流计算，优化调整 220kV侧等值负荷功率，满足等值前后***潮流基本一致； 11-3. After the equivalent value, the power flow calculation is performed, and the equivalent load power of the 220kV side is optimized and adjusted, and the system currents before and after the equivalent value are basically consistent;

11-4、对等值后进行短路计算，优化调整发电机升压变压器电抗，满足等值前后***短路电流基本一致； 11-4. Perform short-circuit calculation after the equivalence value, optimize and adjust the reactance of the generator step-up transformer, and satisfy the short-circuit current of the system before and after the equivalent value;

11-5、对等值后***进行时域仿真，对于等值前后相应的动态仿真曲线，计算评价指标，如满足要求，采用此模型；如若不能满足要求，则进行进一步分析，考虑对模型进行微调。 11-5. After the equivalence, the system performs time domain simulation. For the corresponding dynamic simulation curve before and after the equivalence, calculate the evaluation index. If the requirements are met, use this model. If the requirements are not met, further analysis is performed, and the model is considered. Fine tune.

12. 按照权利要求 11 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的对模型进行微调，包括弱化励磁***调压能力和调整原动机及调速器调频能力。 12. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 11, wherein the model is fine-tuned, including weakening the excitation system, adjusting the prime mover and adjusting the speed. Tuning ability.

13. 按照权利要求 1所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是在对所述的区内低电压网络进行等值简化时，对预想故障集内的相关母线或线路施加短路故障，抽取部分节点作为代表节点计算其残压，根据代表节点的残压情况，在区内中进一步划分各子区域；对于残压较低的子区域，考虑等值为发电机加负荷；对于残压较高的子区域，先等值为负荷，然后根据等值前后动态特性和直接连入 500kV ***机组的容量和动能比重情况选择是否增大直接连入 500kV***机组的容量和动能，即近似加等值机，使等值后发电机组的整体容量和动能与等值前大致相同。 13. The dynamic equivalent method for an AC/DC hybrid large power grid based on an engineering application according to claim 1, wherein when the low voltage network in the region is simplified in an equivalent manner, the expected fault set is A short circuit fault is applied to the relevant bus or line, and some nodes are extracted as representative nodes to calculate the residual voltage. According to the residual voltage of the representative node, each sub-area is further divided in the area; for the sub-area with lower residual voltage, consider The equivalent value is the generator load; for the sub-area with higher residual pressure, the load is equal to the load, and then according to the dynamic characteristics before and after the equivalent value and the capacity and kinetic energy ratio directly connected to the 500kV system unit, whether to increase the direct connection The capacity and kinetic energy of the 500kV system unit is approximately equal to the equal value machine, so that the overall capacity and kinetic energy of the equivalent generator set are approximately the same as before.

14. 按照权利要求 13 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是为了确定所述各子区域的具体等值方案，对部分子区域采用发电机加负荷和近似加等值机两种等值方案后所获得的动态特性曲线进行比较分析；若对某子区域两种不同等值方案的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前偏差较大，发电机加负荷的动态特性曲线与等值前拟合程度较好，则对该子区域采用发电机加负荷的等值方案； 14. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 13, characterized in that in order to determine a specific equivalent scheme of the sub-regions, a generator load is applied to some sub-regions. Comparing and analyzing the dynamic characteristic curves obtained by approximating the two equal-value schemes of equal-equalizers; if the dynamic characteristic curves of two different equivalence schemes in a sub-area are compared and analyzed, all the equivalent dynamic characteristics of the load are The deviation from the pre-equal deviation is large, and the dynamic characteristic curve of the generator plus load is well fitted to the equi-valued front, and the equivalent scheme of the generator plus load is adopted for the sub-area;

若对某子区域等值前后的动态特性曲线进行比较分析，全部等值为负荷的动态特性曲线与等值前的拟合程度就己较好，则不需等值为发电机加负荷。 If the dynamic characteristic curves before and after the equivalence of a sub-area are compared and analyzed, all the equivalent values of the dynamic characteristic curve of the load and the pre-equalization degree are better, and the equivalent load is not required.

15. 按照权利要求 1所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是在对所述区外电网动态等值以及区内电网动态等值之后，均分别对等值效果进行校核；所述的对等值效果进行校核，包括进行动态稳定校核。 15. The dynamic equivalent method for an AC/DC hybrid large power grid based on an engineering application according to claim 1, wherein after the dynamic equivalent of the external power grid and the dynamic equivalent of the power grid in the area, respectively, The equivalent effect is checked; the equivalent effect is checked, including dynamic stability check.

16. 按照权利要求 15 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态稳定校核是比较区内电网和等值后的区内电网在相同的故障扰动下，发电机功角、母线电压以及线路有功功率的变化曲线是否接近，变化规律是否相似，以检验动态等值的效果。 16. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 15, wherein said dynamic stability check is to compare the regional power grid with the equivalent regional power grid. Under the fault disturbance, whether the generator power angle, the bus voltage and the line active power change curve are close, and the change laws are similar to test the effect of dynamic equivalence.

17. 按照权利要求 15 所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是在进行所述动态稳定校核时，选取具有代表性的发电机、直流落点附近的 500kV和 lOOOkV母线、 500kV和 1000kV线路等元件；在同一故障扰动下，将等值前后这些元件物理量的变化曲线绘制在一起，比较两条曲线的初始值、稳态值以及仿真时间段内的变化规律是否一致或相近； 17. The dynamic equivalent method for an AC/DC hybrid large power grid based on engineering application according to claim 15, wherein when the dynamic stability check is performed, a representative generator and a DC drop point are selected. Components of 500kV and lOOOOk busbars, 500kV and 1000kV lines; under the same fault disturbance, draw the curves of the physical quantities of these components before and after the equivalent, compare the initial values of the two curves, the steady-state value and the simulation period Whether the laws of change are consistent or similar;

如果二者相近，表明简化电网与原电网在故障扰动下具有相同的动态响应特性，动态等值效果良好； If the two are similar, it means that the simplified grid has the same dynamic response characteristics as the original grid under fault disturbance, and the dynamic equivalent effect is good;

如果二者差别较大，则需要修改等值方案，重新进行等值。 If the difference between the two is large, you need to modify the equivalent scheme and re-equalize the value.

18. 按照权利要求 1所述的基于工程应用的交直流混联大电网的动态等值方法，其特征是所述的动态等值方法采用相对均方根误差 RMS指标来衡量等值前后***在相同扰动下的动态响应是否一致； 18. The dynamic equivalence method for an AC/DC hybrid large power grid based on engineering application according to claim 1, wherein the dynamic equivalence method uses a relative root mean square error RMS index to measure the system before and after the equivalent value. Whether the dynamic response under the same disturbance is consistent;

所述的相对均方根误差 RMS为等值前后动态曲线各点绝对误差的均方根与等值前曲线各点的均方根的比值，即 The relative root mean square error RMS is the mean square of the absolute error of each point of the dynamic curve before and after the equivalence The ratio of the root to the root mean square of each point of the curve before the equivalence, ie

在计算相对均方根误差 RMS时，只选取预想故障下线路有功功率等值前后的动态曲线进行定量分析。 When calculating the relative root mean square error RMS, only the dynamic curves before and after the line active power equivalent under the expected fault are selected for quantitative analysis.