CN114498586B - A grid current protection setting method and device for high proportion fluctuating power supply - Google Patents
A grid current protection setting method and device for high proportion fluctuating power supply Download PDFInfo
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Abstract
Description
技术领域technical field
本发明涉及一种针对高比例波动性电源的电网电流保护整定方法及装置，属于继电保护技术领域。The invention relates to a power grid current protection setting method and device for a high-ratio fluctuating power supply, and belongs to the technical field of relay protection.
背景技术Background technique
随着可再生能源的发展，基于可再生能源发电的逆变器电源被大量接入电网，逆变器电源在电网电源中的占比不断提高。传统旋转发电机在故障后依靠自身惯性输出电流，短时间内故障电流可以达到额定电流的20～50倍，且与故障回路的等效阻抗呈现线性关系，因此可获取充分的故障信息。With the development of renewable energy, a large number of inverter power supplies based on renewable energy power generation are connected to the grid, and the proportion of inverter power supplies in the grid power supply continues to increase. The traditional rotating generator relies on its own inertia to output current after a fault, and the fault current can reach 20 to 50 times the rated current in a short period of time, and it has a linear relationship with the equivalent impedance of the fault circuit, so sufficient fault information can be obtained.
与传统的旋转电机相比，逆变器电源等效阻抗小、响应速度快，同时能承受的故障电流也较小，只相当于额定电流的1.0～2.0倍，因此当逆变器电源发生故障时，由于逆变器电源自身结构以及内部电力电子器件的限制，会迅速闭锁自身功率器件的输出，无法输出足够的故障信息。电网短路后众多相关逆变器的限流控制综合影响，造成电网短路电流幅值较小且具有较强的非线性特性，影响了传统电网电流保护选择性与灵敏性，对传统电流保护的适用性造成了严重的影响。Compared with traditional rotating motors, the equivalent impedance of the inverter power supply is small, the response speed is fast, and the fault current that can be tolerated is also small, which is only equivalent to 1.0 to 2.0 times the rated current. Therefore, when the inverter power supply fails At this time, due to the structure of the inverter power supply itself and the limitations of the internal power electronic devices, the output of its own power devices will be blocked quickly, and sufficient fault information cannot be output. After the power grid is short-circuited, the combined influence of the current-limiting control of many related inverters causes the grid short-circuit current to have a small amplitude and strong nonlinear characteristics, which affects the selectivity and sensitivity of the traditional power grid current protection, and is applicable to the traditional current protection Sex has serious consequences.
完全应用基于旋转同步电机的传统电源的电网结构如图1所示，传统旋转发电机在故障后依靠自身惯性输出电流，短时间内故障电流可以达到额定电流的20～50倍，可以在故障电流Ik中获取充分的故障信息，传统分段式电流保护可以快速有效地切除故障，完成保护动作。The power grid structure that completely applies the traditional power supply based on the rotating synchronous motor is shown in Figure 1. The traditional rotating generator relies on its own inertia to output current after a fault, and the fault current can reach 20 to 50 times the rated current in a short period of time. With sufficient fault information obtained in Ik , the traditional segmented current protection can quickly and effectively remove the fault and complete the protection action.
完全应用基于逆变器的高比例新能源发电电源的电网结构如图2所示，由于逆变器电源等效阻抗小、响应速度快，同时能承受的故障电流也较小，只相当于额定电流的1.0～2.0倍，因此当逆变器电源发生故障时，由于逆变器电源自身结构以及内部电力电子器件的限制，会迅速闭锁自身功率器件的输出，无法输出足够的故障信息。电网短路后众多相关逆变器的限流控制综合影响，造成电网短路电流幅值较小且具有较强的非线性特性，影响了传统电网电流保护选择性与灵敏性，对传统电流保护的适用性造成了严重的影响。The structure of the power grid that fully applies the high-proportion new energy power generation based on the inverter is shown in Figure 2. Because the equivalent impedance of the inverter power supply is small, the response speed is fast, and the fault current that can be tolerated is also small, it is only equivalent to the rated 1.0 to 2.0 times the current, so when the inverter power supply fails, due to the structure of the inverter power supply itself and the limitations of internal power electronic devices, it will quickly block the output of its own power devices and cannot output enough fault information. After the power grid is short-circuited, the combined influence of the current-limiting control of many related inverters causes the grid short-circuit current to have a small amplitude and strong nonlinear characteristics, which affects the selectivity and sensitivity of the traditional power grid current protection, and is applicable to the traditional current protection Sex has serious consequences.
随着矿藏及化石资源的逐渐枯竭，可再生能源的快速发展，基于可再生能源发电的逆变器电源被大量接入电网，逆变器电源在电网电源中的占比不断提高。由于逆变器电源自身限制，发生短路故障时，会自动限幅或闭锁输出，当电网中逆变器电源占比较高时，故障电流无法输出足够多的故障信息，原有的电流保护将会失去选择性，无法准确动作。With the gradual depletion of mineral and fossil resources and the rapid development of renewable energy, a large number of inverter power supplies based on renewable energy power generation are connected to the grid, and the proportion of inverter power supplies in the grid power supply continues to increase. Due to the limitation of the inverter power itself, when a short-circuit fault occurs, the output will be automatically limited or blocked. When the inverter power ratio in the grid is high, the fault current cannot output enough fault information, and the original current protection will Loss of selectivity, unable to move accurately.
发明内容Contents of the invention
本发明的目的在于克服现有技术中的不足，提供一种针对高比例波动性电源的电网电流保护整定方法，提高逆变器电源电网电流保护选择性和灵敏性。The purpose of the present invention is to overcome the deficiencies in the prior art, provide a grid current protection setting method for a high-ratio fluctuating power supply, and improve the selectivity and sensitivity of inverter power grid current protection.
为达到上述目的，本发明是采用下述技术方案实现的：In order to achieve the above object, the present invention is achieved by adopting the following technical solutions:
第一方面，本发明提供了一种针对高比例波动性电源的电网电流保护整定方法，包括以下步骤：In the first aspect, the present invention provides a grid current protection setting method for a high-ratio fluctuating power supply, comprising the following steps:
步骤1：在线辨识获取电网的电源构成占比；所述电网至少包括传统同步电机电源与逆变器电源；Step 1: Online identification and acquisition of the power composition ratio of the power grid; the power grid includes at least traditional synchronous motor power and inverter power;
步骤2：采集实测短路电流信息；Step 2: Collect the measured short-circuit current information;
步骤3：根据所述电源构成占比，将所述实测短路电流信息折算为相应的等效故障电流值；Step 3: Convert the measured short-circuit current information into a corresponding equivalent fault current value according to the composition ratio of the power supply;
步骤4：根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定。Step 4: Judge the section where the fault occurs based on the converted short-circuit current value, and perform segmented current protection setting according to the section where the fault occurs.
进一步的，根据所述电源构成占比，将所述实测短路电流信息折算为相应的短路电流值的方法包括：Further, according to the proportion of the power supply, the method of converting the measured short-circuit current information into a corresponding short-circuit current value includes:
步骤1：根据下式计算获得逆变器电源发生故障后输出的限制电流Ik2：Step 1: Calculate and obtain the output limiting current I k2 after the inverter power supply fails according to the following formula:
Ik2＝kIN；I k2 =k I N ;
式中，IN为逆变器电源额定输出电流，k为比例系数；In the formula, I N is the rated output current of the inverter power supply, and k is the proportional coefficient;
步骤2：根据所述电源构成占比，将其中的逆变器电源等效替换为同等容量的传统旋转电源，计算出用同等容量的传统旋转电源替换电网中的逆变器电源后得到的等效故障电流Ik2′；Step 2: According to the proportion of the power supply, replace the inverter power supply with the traditional rotating power supply of the same capacity, and calculate the equivalent power obtained after replacing the inverter power supply in the grid with the traditional rotating power supply of the same capacity. Effective fault current I k2 ′;
步骤3：根据下式计算得出逆变器电源被替换后得到的等效故障电流值Ik′；Step 3: Calculate the equivalent fault current value I k ′ obtained after the inverter power supply is replaced according to the following formula;
Ik'＝(Ik-Ik2)+Ik2'I k '＝(I k -I k2 )+I k2 '
式中，Ik′为等效故障电流值，Ik为实测短路电流信息。In the formula, I k ′ is the equivalent fault current value, and I k is the measured short-circuit current information.
进一步的，根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定的方法包括：Further, according to the converted short-circuit current value, the section where the fault occurs is judged, and the method for segmented current protection setting according to the section where the fault occurs includes:
根据等效故障电流值Ik′与电流Ⅰ段动作电流整定值和电流Ⅱ段动作电流整定值的比较，判断故障发生的区段，进行相应的保护动作，具体包括以下步骤：According to the comparison of the equivalent fault current value I k ′ with the operating current setting value of the current section I and the operating current setting value of the current section II, the section where the fault occurs is judged, and the corresponding protection action is carried out, which specifically includes the following steps:
步骤1：判断保护是否启动，若是则判断等效故障电流值Ik′是否大于电流Ⅰ段动作电流整定，若否则返回读取电源构成占比在线辨识结果；Step 1: Judging whether the protection is activated, if so, judging whether the equivalent fault current value I k ′ is greater than the operating current setting of the first stage of the current, if not, return to read the online identification result of the proportion of the power supply;
步骤2：保护起动，若等效故障电流值Ik′大于电流Ⅰ段动作电流整定值，且在ΔtⅠ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；Step 2: Protection starts. If the equivalent fault current value I k ′ is greater than the operating current setting value of the current stage I and maintains this relationship within Δt I , return to read the actual measured value of the current after issuing the trip command. If it is not maintained, Then directly return the measured value of the read current;
步骤3：若等效故障电流值Ik′不大于电流Ⅰ段动作电流整定值，则判断等效故障电流值Ik′是否大于电流Ⅱ段动作电流整定值，若大于且在ΔtⅡ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；Step 3: If the equivalent fault current value I k ′ is not greater than the operating current setting value of the current stage I, then judge whether the equivalent fault current value I k ′ is greater than the operating current setting value of the current stage II, if it is greater than and maintain within Δt Ⅱ In this relationship, after the trip command is issued, it will return to read the actual measured value of the current. If it is not maintained, it will directly return to read the actual measured value of the current;
步骤4：若等效故障电流值Ik′不大于电流Ⅱ段动作电流整定值，则再次判断保护是否启动，若是则跳转读取电流实测值，若否则返回读取电源构成占比在线辨识结果。Step 4: If the equivalent fault current value I k ′ is not greater than the operating current setting value of current stage II, then judge again whether the protection is activated, if so, jump to read the actual measured value of the current, otherwise return to read the online identification of the proportion of the power supply result.
进一步的，所述电流Ⅰ段动作电流整定值由按照总电源容量最大且历史实测的逆变器电源占比最小为边界构建电网的运行方式计算得出，如下式：Further, the operation current setting value of the current stage I is calculated by the operation mode of the power grid constructed according to the maximum total power supply capacity and the minimum historically measured inverter power supply ratio as the boundary, as shown in the following formula:
其中，
进一步的，所述电流Ⅱ段动作电流整定值由按照总电源容量最小且历史实测的逆变器电源占比最大为边界构建电网的运行方式计算得出，如下式：Further, the operation current setting value of the second stage of the current is calculated by the operation mode of the power grid constructed according to the boundary of the minimum total power supply capacity and the maximum historically measured inverter power supply ratio, as follows:
其中，
按在系统“最小运行方式”下本线路末端两相金属性短路时的等效短路电流值
其中，Ksen为灵敏度。Among them, K sen is the sensitivity.
进一步的，流经短路点的故障电流Ik、逆变器电源额定输出电流IN由现有测量装置直接测得。Furthermore, the fault current I k flowing through the short-circuit point and the rated output current I N of the inverter power supply are directly measured by existing measuring devices.
第二方面，本发明提供一种针对高比例波动性电源的电网电流保护整定装置，所述装置包括：In the second aspect, the present invention provides a power grid current protection setting device for a high-ratio fluctuating power supply, the device comprising:
获取模块：用于在线辨识获取电网的电源构成占比；所述电网至少包括传统同步电机电源与逆变器电源；Acquisition module: used for online identification and acquisition of the power composition ratio of the power grid; the power grid includes at least traditional synchronous motor power and inverter power;
槽口模块：用于采集实测短路电流信息；Notch module: used to collect measured short-circuit current information;
折算模块：用于根据所述电源构成占比，将所述实测短路电流信息折算为相应的等效故障电流值；Conversion module: used to convert the measured short-circuit current information into a corresponding equivalent fault current value according to the proportion of the power supply;
区域判断模块：用于根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定。Area Judgment Module: It is used to judge the section where the fault occurs according to the converted short-circuit current value, and perform segmented current protection setting according to the section where the fault occurs.
进一步的，所述折算模块根据所述电源构成占比，将所述实测短路电流信息折算为相应的短路电流值的方法包括：Further, the conversion module converts the measured short-circuit current information into a corresponding short-circuit current value according to the proportion of the power supply, including:
根据下式计算获得逆变器电源发生故障后输出的限制电流Ik2：Calculate the output limit current I k2 after the inverter power supply fails according to the following formula:
Ik2＝kIN；I k2 =k I N ;
式中，IN为逆变器电源额定输出电流，k为比例系数；In the formula, I N is the rated output current of the inverter power supply, and k is the proportional coefficient;
根据所述电源构成占比，将其中的逆变器电源等效替换为同等容量的传统旋转电源，计算出用同等容量的传统旋转电源替换电网中的逆变器电源后得到的等效故障电流Ik2′；According to the proportion of the power supply, the inverter power supply is equivalently replaced with a traditional rotating power supply of the same capacity, and the equivalent fault current obtained after replacing the inverter power supply in the power grid with a traditional rotating power supply of the same capacity is calculated I k2 ';
根据下式计算得出逆变器电源被替换后得到的等效故障电流值Ik′；The equivalent fault current value I k ′ obtained after the inverter power supply is replaced is calculated according to the following formula;
Ik'＝(Ik-Ik2)+Ik2'I k '＝(I k -I k2 )+I k2 '
式中，Ik′为等效故障电流值，Ik为实测短路电流信息。In the formula, I k ′ is the equivalent fault current value, and I k is the measured short-circuit current information.
进一步的，所述区域判断模块根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定的方法包括：Further, the area judging module judges the section where the fault occurs according to the converted short-circuit current value, and the method of segmented current protection setting according to the section where the fault occurs includes:
根据等效故障电流值Ik′与电流Ⅰ段动作电流整定值和电流Ⅱ段动作电流整定值的比较，判断故障发生的区段，进行相应的保护动作，具体包括以下步骤：According to the comparison of the equivalent fault current value I k ′ with the operating current setting value of the current section I and the operating current setting value of the current section II, the section where the fault occurs is judged, and the corresponding protection action is carried out, which specifically includes the following steps:
判断保护是否启动，若是则判断等效故障电流值Ik′是否大于电流Ⅰ段动作电流整定，若否则返回读取电源构成占比在线辨识结果；Judging whether the protection is activated, if so, judging whether the equivalent fault current value I k ′ is greater than the operating current setting of the first stage of the current, if not, return to read the online identification result of the proportion of the power supply;
保护起动，若等效故障电流值Ik′大于电流Ⅰ段动作电流整定值，且在ΔtⅠ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；When the protection starts, if the equivalent fault current value I k ′ is greater than the action current setting value of the current stage Ⅰ, and this relationship is maintained within Δt Ⅰ , then return to read the actual measured value of the current after issuing the trip command, if not, return directly to Read the measured current value;
若等效故障电流值Ik′不大于电流Ⅰ段动作电流整定值，则判断等效故障电流值Ik′是否大于电流Ⅱ段动作电流整定值，若大于且在ΔtⅡ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；If the equivalent fault current value I k ′ is not greater than the operating current setting value of current stage I, then judge whether the equivalent fault current value I k ′ is greater than the operating current setting value of current stage II, if it is greater than and maintain this relationship within ΔtⅡ , then return to read the actual measured value of current after issuing the trip command, if not, return directly to read the actual measured value of current;
若等效故障电流值Ik′不大于电流Ⅱ段动作电流整定值，则再次判断保护是否启动，若是则跳转读取电流实测值，若否则返回读取电源构成占比在线辨识结果。If the equivalent fault current value I k ′ is not greater than the operating current setting value of current stage II, then judge again whether the protection is activated, if so, jump to read the actual measured value of the current, otherwise return to read the online identification result of the proportion of the power supply.
第三方面，本发明提供一种针对高比例波动性电源的电网电流保护整定装置，包括处理器及存储介质；In a third aspect, the present invention provides a power grid current protection setting device for a high-ratio fluctuating power supply, including a processor and a storage medium;
所述存储介质用于存储指令；The storage medium is used to store instructions;
所述处理器用于根据所述指令进行操作以执行根据第一方面所述方法的步骤。The processor is configured to operate in accordance with the instructions to perform the steps of the method according to the first aspect.
与现有技术相比，本发明所达到的有益效果：Compared with the prior art, the beneficial effects achieved by the present invention are as follows:
(1)本发明针对含有高比例逆变器电源的电网中，电网短路后众多相关逆变器的限流控制综合影响，造成电网短路电流幅值较小且具有较强的非线性特性的问题，折算出一种相比实测短路电流值放大了的虚拟短路电流值，同时该虚拟短路电流值是近似线性化的，本发明根据折算后的短路电流值可判断故障发生的区段，满足选择性需求。(1) The present invention is aimed at the power grid containing a high proportion of inverter power supply, the comprehensive influence of the current limiting control of many related inverters after the power grid is short-circuited, resulting in the problem that the amplitude of the short-circuit current of the power grid is small and has strong nonlinear characteristics , to convert a virtual short-circuit current value that is amplified compared with the measured short-circuit current value, and the virtual short-circuit current value is approximately linear. The present invention can judge the section where the fault occurs according to the converted short-circuit current value, satisfying the selection sexual needs.
(2)本发明弥补了现有电网电流保护难以适应电源侧高比例新能源发电电源的缺陷，使得改进后的电网电流保护整定方法充分考虑了灵敏性要求。传统电网考虑灵敏性问题，主要是针对同步发电机开机情况(最大最小运行方式的区别)，而新型电网中波动性电源的并网情况并不能用传统的大小方式表达。本发明提出了一种新的整定校核方法，并据此进行分段式电流保护整定，满足灵敏性需求。(2) The present invention makes up for the defect that the existing grid current protection is difficult to adapt to the high proportion of new energy power generation on the power supply side, so that the improved grid current protection setting method fully considers the sensitivity requirement. The traditional power grid considers the sensitivity problem, mainly for the start-up situation of the synchronous generator (the difference between the maximum and the minimum operation mode), while the grid-connected situation of the fluctuating power supply in the new power grid cannot be expressed in the traditional size way. The invention proposes a new setting and checking method, and based on this, segmental current protection setting is performed to meet the sensitivity requirement.
(3)本发明提出的一种针对高比例波动性电源的电网电流保护整定方法，可以利用原有电网电流保护装置，无需改变电路结构，且具有一定的自适应能力，具有较高的工程实用性。(3) A power grid current protection setting method for high-proportion fluctuating power sources proposed by the present invention can use the original power grid current protection device without changing the circuit structure, and has a certain self-adaptive ability and high engineering practicality sex.
附图说明Description of drawings
图1为完全应用基于旋转同步电机的传统电源的电网结构示意图；Figure 1 is a schematic diagram of the grid structure that completely applies a traditional power supply based on a rotating synchronous motor;
图2为完全应用基于逆变器的高比例新能源发电电源的电网结构示意图；Figure 2 is a schematic diagram of the grid structure that fully applies inverter-based high-proportion new energy power generation;
图3为基于旋转同步电机的传统电源与基于逆变器的高比例新能源发电电源相混合的电网结构与电源等效替代后的电网结构的相互转换图；Figure 3 is a mutual conversion diagram of the power grid structure based on the traditional power supply based on the rotating synchronous motor and the high-proportion new energy power generation power based on the inverter and the grid structure after the equivalent replacement of the power supply;
图4为电源构成占比在线辨识原理图；Figure 4 is a schematic diagram of the online identification of the proportion of the power supply;
图5为针对高比例波动性电源的电网电流保护动作流程。Figure 5 is the action flow of grid current protection for high proportion fluctuating power supply.
具体实施方式Detailed ways
下面结合附图对本发明作进一步描述。以下实施例仅用于更加清楚地说明本发明的技术方案，而不能以此来限制本发明的保护范围。The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.
实施例一：Embodiment one:
基于现有电网电流保护难以适应电源侧高比例新能源发电电源的缺陷，本实施例提出了一种针对高比例波动性电源的电网电流保护整定方法，在面向未来高比例新能源发电电源的电网中，对实现性能良好的继电保护功能具有较高的工程实用性。Based on the fact that the existing power grid current protection is difficult to adapt to the defect of the high proportion of new energy power generation on the power supply side, this embodiment proposes a grid current protection setting method for high proportion of fluctuating power sources, which will be used in power grids with a high proportion of new energy power generation in the future. Among them, it has high engineering practicability to realize the relay protection function with good performance.
本实施例提供的一种针对高比例波动性电源的电网电流保护整定方法，具体方法为根据短路故障发生前测得的不同类型电源占比，将其中的逆变器电源等效替换为同等容量的传统旋转电源，从而构建一个“虚拟电源端”，即从保护安装处看来其电源侧只包含旋转电机，进而用于稳态分析计算。短路发生后采集实测短路电流信息，将其修改为对应上述“虚拟电源端”的虚拟短路电流，即想象中替换电源侧的逆变器电源，替换原则为保持电源总容量不变，同时将电源组成成分完全转换为传统旋转电机，然后折算出的相应的短路电流值测量值。进而，根据折算后的短路电流值判断故障发生的区段(满足选择性需求)，并据此进行分段式电流保护整定(满足灵敏性需求)。This embodiment provides a grid current protection setting method for high-proportion fluctuating power sources. The specific method is to replace the inverter power sources with equivalent capacity according to the proportions of different types of power sources measured before the short-circuit fault occurs. In order to construct a "virtual power supply end", that is, from the point of view of the protection installation, the power supply side only contains the rotating motor, which is then used for steady-state analysis and calculation. After the short circuit occurs, collect the measured short-circuit current information and modify it to the virtual short-circuit current corresponding to the above-mentioned "virtual power supply terminal", that is, replace the inverter power supply on the power supply side in imagination. The replacement principle is to keep the total capacity of the power supply unchanged, and at the same time replace the The composition is completely converted to that of a traditional rotating electrical machine, and then the corresponding short-circuit current value is converted to the measured value. Furthermore, according to the converted short-circuit current value, the section where the fault occurs is judged (satisfying the selective requirement), and the subsection current protection setting is performed accordingly (satisfying the sensitivity requirement).
数学计算步骤为：The mathematical calculation steps are:
步骤一、测量出电网发生短路故障后，流经短路点的故障电流Ik；Step 1. Measure the fault current I k flowing through the short-circuit point after a short-circuit fault occurs in the power grid;
步骤二、计算获得逆变器电源发生故障后输出的限制电流Ik2，根据逆变器电源特性可知Ik2＝kIN；式中，IN为逆变器电源额定输出电流，k为比例系数，可取1.0～2.0(由电力电子开关器件的过流能力确定)；Step 2. Calculate and obtain the limited current I k2 output after the inverter power supply fails. According to the characteristics of the inverter power supply, I k2 =kIN; where I N is the rated output current of the inverter power supply, and k is the proportional coefficient , preferably 1.0 to 2.0 (determined by the overcurrent capability of the power electronic switching device);
步骤三、计算出用同等容量的传统旋转电源替换电网中的逆变器电源后得到的等效故障电流Ik2'；Step 3. Calculate the equivalent fault current I k2 ' obtained after replacing the inverter power supply in the grid with a traditional rotating power supply of the same capacity;
步骤五、计算得出逆变器电源被替换后得到的等效故障电流值Ik'，其中，Ik'＝(Ik-Ik2)+Ik2'；Step 5. Calculate the equivalent fault current value I k ' obtained after the inverter power supply is replaced, where I k '=(I k -I k2 )+I k2 ';
步骤六、根据计算得出的等效故障电流值Ik'，根据等效故障电流值Ik'与电流分段式保护整定值的比较，判断故障发生的区段，进行相应的保护动作。Step 6: According to the calculated equivalent fault current value I k ', according to the comparison between the equivalent fault current value I k ' and the setting value of the current segmental protection, determine the section where the fault occurs, and perform corresponding protection actions.
其中，流经短路点的故障电流Ik、逆变器电源额定输出电流IN可由现有测量装置直接测得。Among them, the fault current I k flowing through the short-circuit point and the rated output current I N of the inverter power supply can be directly measured by existing measuring devices.
下面结合附图对本发明作更进一步的说明。The present invention will be further described below in conjunction with the accompanying drawings.
传统旋转电机与逆变器电源混合发电的电网结构如图3上半部分所示，用同等容量的传统旋转电源替换电网中的逆变器电源(如图3下半部分所示)，计算得出逆变器电源被替换后得到的等效故障电流值Ik'后，可对所述电网进行分段式电网电流保护。The power grid structure of the hybrid power generation of traditional rotating motor and inverter power is shown in the upper part of Fig. 3, and the inverter power in the power grid is replaced with the traditional rotating power source of the same capacity (as shown in the lower part of Fig. 3), and the calculated After the equivalent fault current value I k ' obtained after the inverter power supply is replaced, the segmented grid current protection can be performed on the grid.
以下整定值均按逆变器电源被同等容量旋转电机电源替换后的电网整定，其中，高比例波动性电源的电网与传统电网在最大(最小)运行方式上存在较大差异，传统电网电源由旋转发电机构成并满足负荷需求，因此电源的最大(最小)运行方式所处时间段较为固定。而所述高比例波动性电源的电网中，电源的最大(最小)运行状态需要适应不同地点不同时段新能源发电相关的逆变器状态不同，需要经在线辨识并统计归纳，得出整定过程所需基础数据。The following setting values are all set according to the power grid after the inverter power supply is replaced by the rotating motor power supply of the same capacity. Among them, there is a big difference between the power grid with a high proportion of fluctuating power supply and the traditional power grid in the maximum (minimum) operation mode. The rotating generator constitutes and satisfies the load demand, so the maximum (minimum) operation mode of the power supply is in a relatively fixed time period. In the power grid with a high proportion of fluctuating power sources, the maximum (minimum) operating state of the power source needs to adapt to the different states of the inverters related to new energy power generation in different locations and at different times. Basic data is required.
整定的基本原理为：按照总电源容量最大且历史实测的逆变器电源占比最小为边界构建所述“最大运行方式”，计算相应的短路电流值，用于电流保护的整定，保障在线辨识模块更新不及时的情况下电流保护不会发生误动作，满足选择性需求；按照总电源容量最小且历史实测的逆变器电源占比最大为边界构建所述“最小运行方式”，计算出最小的短路电流，用于保护性能校核，满足灵敏性要求。The basic principle of the setting is: construct the "maximum operation mode" according to the maximum total power capacity and the minimum historically measured inverter power ratio as the boundary, calculate the corresponding short-circuit current value, and use it for current protection setting to ensure online identification If the module is not updated in time, the current protection will not malfunction and meet the selective requirements; the "minimum operation mode" is constructed according to the boundary of the minimum total power capacity and the largest proportion of inverter power measured in history, and the minimum operation mode is calculated. The short-circuit current is used to check the protection performance and meet the sensitivity requirements.
为了保证电流速断(电流Ⅰ段)保护动作的选择性，对保护2来讲，“保护2”为附图3下半部分中安装的2号保护，动作电流按躲过系统“最大运行方式”下，本线路末端即下条线路首端(B)发生三相短路时，流经本保护的等效最大短路电流
其中，
该保护通过动作值
限时电流速断(电流Ⅱ段)保护要求保护线路全长，其保护范围必然延伸到下一线路，与下一线路电流保护范围重叠。当下一线路出口发生短路时，保护1的电流Ⅰ段与保护2的电流Ⅱ段将同时起动，为了保证选择性，并力求降低保护的动作时间，电流Ⅱ段与下一线路电流Ⅰ段进行配合整定，要求保护范围小于下一线路电流Ⅰ段保护范围且动作时限
其中，
限时电流速断(电流Ⅱ段)保护灵敏度按被保护线路末端短路时本保护的最小等效短路电流计算，即按在系统“最小运行方式”下本线路末端两相金属性短路时的等效短路电流值
其中，Ksen为灵敏度(有一定数值范围要求，具体数值有待工程经验积累)。Among them, K sen is the sensitivity (a certain value range is required, and the specific value is subject to the accumulation of engineering experience).
若灵敏度不满足要求，限时电流速断保护(电流Ⅱ段)保护与下条线路电流Ⅱ段配合整定：If the sensitivity does not meet the requirements, the time-limited current quick-break protection (current section II) protection is coordinated with the next line current section II:
其中，Krel为可靠系数(具体数值有待工程经验积累)，
电源容量占比在线测量辨识的基本原理：The basic principle of online measurement and identification of power capacity ratio:
本实施例的方法基于一种电网中传统旋转电机与逆变器电源容量占比的在线测量辨识程序，已经完成了电网电源侧两种电源容量占比的辨识。The method in this embodiment is based on an on-line measurement and identification program for the proportion of the power supply capacity of the traditional rotating electrical machine and the inverter in the power grid, and the identification of the capacity proportions of the two power sources on the power grid side has been completed.
该辨识方法的原理为：已经通过保护安装处相应的母线电压测量回路和所保护线路的电流测量回路，在线持续地辨识出电源方向(侧)的构成成分比例，并存储至保护装置中。辨识模型如图4所示，扰动源为线路侧的较大负荷波动或短路故障，因此该辨识方法具有一定的时变跟踪性能。The principle of this identification method is: through the corresponding busbar voltage measurement circuit at the protection installation and the current measurement circuit of the protected line, the composition ratio of the power supply direction (side) is continuously identified online, and stored in the protection device. The identification model is shown in Figure 4. The disturbance source is a large load fluctuation or short-circuit fault on the line side, so the identification method has certain time-varying tracking performance.
通常情况下，可以将传统旋转电机视为电压源，将逆变器电源视为受控电流源，因电压源和电流源的响应特性不同，给该系统一定的扰动信号(如负荷侧的大功率设备投切)后，保护安装处的电压/电流响应信息也会随着电源构成占比的不同而不同，从而可得到此时电网中逆变器电源和传统旋转发电机各自的占比。电源侧的实际电源设备众多，但同步机基本上是恒定电压源，逆变器基本上满足电流受控的特性，因此该模型结构可视为将传统旋转电机和逆变器电源进行等效合并(利用戴维南定理和诺顿定理等)后的等效电源。Usually, the traditional rotating motor can be regarded as a voltage source, and the inverter power supply can be regarded as a controlled current source. Because the response characteristics of the voltage source and the current source are different, a certain disturbance signal is given to the system (such as a large After the switching of power equipment), the voltage/current response information at the protection installation will also vary with the proportion of the power supply, so that the respective proportions of the inverter power supply and the traditional rotating generator in the power grid can be obtained at this time. There are many actual power supply devices on the power supply side, but the synchronous machine is basically a constant voltage source, and the inverter basically satisfies the characteristics of current control, so the model structure can be regarded as an equivalent combination of traditional rotating motor and inverter power supply (using Thevenin's theorem and Norton's theorem, etc.) after the equivalent power supply.
实施例二：Embodiment two:
本实施例提供一种针对高比例波动性电源的电网电流保护整定装置，所述装置包括：This embodiment provides a power grid current protection setting device for a high-ratio fluctuating power supply. The device includes:
获取模块：用于在线辨识获取电网的电源构成占比；所述电网至少包括传统同步电机电源与逆变器电源；Acquisition module: used for online identification and acquisition of the power composition ratio of the power grid; the power grid includes at least traditional synchronous motor power and inverter power;
槽口模块：用于采集实测短路电流信息；Notch module: used to collect measured short-circuit current information;
折算模块：用于根据所述电源构成占比，将所述实测短路电流信息折算为相应的等效故障电流值；Conversion module: used to convert the measured short-circuit current information into a corresponding equivalent fault current value according to the proportion of the power supply;
区域判断模块：用于根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定。Area Judgment Module: It is used to judge the section where the fault occurs according to the converted short-circuit current value, and perform segmented current protection setting according to the section where the fault occurs.
进一步的，所述折算模块根据所述电源构成占比，将所述实测短路电流信息折算为相应的短路电流值的方法包括：Further, the conversion module converts the measured short-circuit current information into a corresponding short-circuit current value according to the proportion of the power supply, including:
根据下式计算获得逆变器电源发生故障后输出的限制电流Ik2：Calculate the output limit current I k2 after the inverter power supply fails according to the following formula:
Ik2＝kIN；I k2 =k I N ;
式中，IN为逆变器电源额定输出电流，k为比例系数；In the formula, I N is the rated output current of the inverter power supply, and k is the proportional coefficient;
根据所述电源构成占比，将其中的逆变器电源等效替换为同等容量的传统旋转电源，计算出用同等容量的传统旋转电源替换电网中的逆变器电源后得到的等效故障电流Ik2′；According to the proportion of the power supply, the inverter power supply is equivalently replaced with a traditional rotating power supply of the same capacity, and the equivalent fault current obtained after replacing the inverter power supply in the power grid with a traditional rotating power supply of the same capacity is calculated I k2 ';
根据下式计算得出逆变器电源被替换后得到的等效故障电流值Ik′；The equivalent fault current value I k ′ obtained after the inverter power supply is replaced is calculated according to the following formula;
Ik'＝(Ik-Ik2)+Ik2'I k '＝(I k -I k2 )+I k2 '
式中，Ik′为等效故障电流值，Ik为实测短路电流信息。In the formula, I k ′ is the equivalent fault current value, and I k is the measured short-circuit current information.
进一步的，所述区域判断模块根据折算后的短路电流值判断故障发生的区段，并根据故障发生的区段进行分段式电流保护整定的方法包括：Further, the area judging module judges the section where the fault occurs according to the converted short-circuit current value, and the method of segmented current protection setting according to the section where the fault occurs includes:
根据等效故障电流值Ik′与电流Ⅰ段动作电流整定值和电流Ⅱ段动作电流整定值的比较，判断故障发生的区段，进行相应的保护动作，具体包括以下步骤：According to the comparison of the equivalent fault current value I k ′ with the operating current setting value of the current section I and the operating current setting value of the current section II, the section where the fault occurs is judged, and the corresponding protection action is carried out, which specifically includes the following steps:
判断保护是否启动，若是则判断等效故障电流值Ik′是否大于电流Ⅰ段动作电流整定，若否则返回读取电源构成占比在线辨识结果；Judging whether the protection is activated, if so, judging whether the equivalent fault current value I k ′ is greater than the operating current setting of the first stage of the current, if not, return to read the online identification result of the proportion of the power supply;
保护起动，若等效故障电流值Ik′大于电流Ⅰ段动作电流整定值，且在ΔtⅠ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；When the protection starts, if the equivalent fault current value I k ′ is greater than the action current setting value of the current stage Ⅰ, and this relationship is maintained within Δt Ⅰ , then return to read the actual measured value of the current after issuing the trip command, if not, return directly to Read the measured current value;
若等效故障电流值Ik′不大于电流Ⅰ段动作电流整定值，则判断等效故障电流值Ik′是否大于电流Ⅱ段动作电流整定值，若大于且在ΔtⅡ内保持这种关系，则发出跳闸指令后返回读取电流实测值，若未保持，则直接返回读取电流实测值；If the equivalent fault current value I k ′ is not greater than the operating current setting value of current stage I, then judge whether the equivalent fault current value I k ′ is greater than the operating current setting value of current stage II, if it is greater than and maintain this relationship within ΔtⅡ , then return to read the actual measured value of current after issuing the trip command, if not, return directly to read the actual measured value of current;
若等效故障电流值Ik′不大于电流Ⅱ段动作电流整定值，则再次判断保护是否启动，若是则跳转读取电流实测值，若否则返回读取电源构成占比在线辨识结果。If the equivalent fault current value I k ′ is not greater than the operating current setting value of current stage II, then judge again whether the protection is activated, if so, jump to read the actual measured value of the current, otherwise return to read the online identification result of the proportion of the power supply.
本实施例的装置可用于实现实施例一所述的方法。The device in this embodiment can be used to implement the method described in the first embodiment.
实施例三：Embodiment three:
本发明实施例还提供了一种针对高比例波动性电源的电网电流保护整定装置，包括处理器及存储介质；The embodiment of the present invention also provides a power grid current protection setting device for a high-ratio fluctuating power supply, including a processor and a storage medium;
所述存储介质用于存储指令；The storage medium is used to store instructions;
所述处理器用于根据所述指令进行操作以实施例一所述方法的步骤。The processor is configured to operate according to the instructions to implement the steps of a method.
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明技术原理的前提下，还可以做出若干改进和变形，这些改进和变形也应视为本发明的保护范围。The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.
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