GB/T 50703-2011 PDF English
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Basic data
| Standard ID | GB/T 50703-2011 (GB/T50703-2011) |
| Description (Translated English) | Code for design of automaticity equipment for power system security |
| Sector / Industry | National Standard (Recommended) |
| Classification of Chinese Standard | P60 |
| Classification of International Standard | 27.100 |
| Word Count Estimation | 43,490 |
| Date of Issue | 2011-07-26 |
| Date of Implementation | 2012-06-01 |
| Quoted Standard | GB/T 14285; GB/T 26399; DL 755 |
| Regulation (derived from) | Bulletin of the Ministry of Housing and Urban No. 1102 |
| Issuing agency(ies) | Ministry of Housing and Urban-Rural Development of the People's Republic of China; General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China |
| Summary | This standard applies to 35 kV and above voltage level of the power system security automatic device design, low voltage level (10kV and below) power system can also perform automatic safety devices designed to this specification. |
GB/T 50703-2011: Code for design of automaticity equipment for power system security
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Sudden large and substantial state changes in power systems due to short circuits or unplanned removal of system components are called accident disturbances. 2.0.9 connection and section connection and section A connection is the combination of grid elements (transmission lines, transformers, etc.) that connects two parts of the power system. Intermediate power plants and load junctions can also be included in the "connection" concept. A section is one or several connected elements that, when disconnected, divide the power system into two independent parts. 3 Calculation and analysis principles for power system security and stability 3.1 Years of stable calculation level 3.1.1 The design level year selected for the calculation and analysis of safety and stability should mainly be the project commissioning year; if the project is put into production in stages, it should also include the transition year. 3.1.2 The grid structure used for calculation should correspond to the design level year. 3.1.3 The calculated load should correspond to the design level year. When the load increase has a significant impact on the system stability, it is advisable to conduct a sensitivity analysis of the impact of the load on the system stability. 3.2 Stable computing operation mode 3.2.1 In the stability calculation, the most unfavorable method for safety and stability should be selected for safety and stability verification for specific verification objects (lines, busbars, main transformers, etc.). 3.2.2 The stable calculation can choose the following operation modes. 1 Normal operation mode. including planned maintenance operation mode and possible operation modes such as hydropower generation, thermal power generation, wind power generation, maximum or minimum load, minimum start-up and pumped storage operating conditions according to the load curve and seasonal changes. 2.Post-accident operation mode. After the power system accident is eliminated, the short-term steady-state operation mode appears before returning to the normal operation mode. 3 Special operation modes. large-scale generator sets, main lines, large-capacity transformers, DC unipolar, series compensation and other equipment maintenance, inter-regional exchange power changes and other modes that have a serious impact on the safe and stable operation of the system. 3.3 Fault Types of Stable Calculation 3.3.1 Stability calculations should consider metallic short-circuit faults at the most unfavorable locations for stability. 3.3.2 The fault belongs to the large accident disturbance suffered by the power system, and the large disturbance can be divided into the types listed in Table 3.3.2 according to the severity and occurrence probability. 3.3.3 The types of faults for safety and stability analysis and calculation should be selected from the type I and type II faults listed in Table 3.3.2, and the type III faults listed in Table 3.3.2 can be analyzed when necessary. 3.4 Stable calculation model and parameters 3.4.1 The model and parameters of synchronous generator and control system shall be selected according to the following provisions. 1 The synchronous generator should adopt the detailed model of subtransient potential change; 2 For synchronous generators that can provide the measured model and parameters, the measured model and parameters should be used; 3 For synchronous generators that cannot provide measured models and parameters, typical models and typical parameters may be used; 4 The parameters of the prime mover and the speed control system should adopt the measured parameters in principle, and the parameters provided by the manufacturer can be used if they cannot be provided; 5 In the planning and design stage or when there are no complete parameters, the larger-capacity synchronous generator can refer to the model and parameters of the same manufacturer and the same capacity unit that have been put into operation. 3.4.2 Commonly used wind turbine models include squirrel-cage asynchronous wind turbines, double-feedback asynchronous wind turbines and direct-drive synchronous wind turbines, and the corresponding models should be selected according to the actual situation. 3.4.3 The load model and parameters shall be determined according to the actual load characteristics of the regional power grid and the procedures used, and shall comply with the following regulations. 1 The model of comprehensive load can be represented by the exponential function of static voltage and frequency and choose an appropriate index. 2 The model of relatively concentrated large-capacity motor load can be represented by an equivalent induction motor load and a parallel static load on the corresponding 110kV (66kV) high-voltage busbar. 3 In the planning and design stage, the load can use the load model with the same characteristics as the area or the constant impedance model. 4 When performing dynamic stability analysis, detailed models should be used. 3.4.4 Other equipment parameters should be selected according to the following regulations. 1 Existing equipment should adopt actual parameters; 2 The design parameters should be adopted for new equipment; 3 In the planning and design stage or when there are no complete parameters, it can be considered according to the typical parameters of the same type of equipment. 3.5 Stable calculation of fault removal time and automatic device action time 3.5.1 The fault clearing time in the stability calculation should include the time from when the circuit breaker is fully disconnected and the relay protection is activated (from the beginning of the fault to the sending of the tripping pulse). The cut-off time of line, main transformer, busbar and DC system faults should be carried out according to the provisions in Table 3.5.1. 3.5.2 The reclosing time is the time from the fault removal to the reclosing of the main breaker, which should be determined according to the actual reclosing setting time of the power grid. 3.5.3 The cut-off time of circuit breaker failure protection action is the sum of element protection or busbar protection action time, failure protection setting delay and circuit breaker tripping time. The sum of element protection or busbar protection action time and circuit breaker trip time can refer to the fault removal time listed in Table 3.5.1, and the failure protection setting delay can be selected according to the following regulations. 1 The failure protection setting delay of one and a half circuit breaker wiring can be 0.2s ~ 0.3s; 2 The setting delay of the failure protection in the form of double-bus connection can be 0.3s~0.5s. 3.5.4 The execution time of the safety and stability control system is the sum of the automatic device action time, channel transmission time, and related circuit breaker trip time (or DC action time), which should be determined according to the actual situation of the system. The execution time of commonly used safety and stability control systems can be selected according to the following provisions. 1 Cut off machine, load off can be 0.2s～0.3s. 2.The DC power modulation response time is preferably 0.1s, and the DC power boost and drop speed can be determined according to the dynamic characteristics and system stability characteristics of the DC system. 3.6 Stable calculation and analysis content 3.6.1 Analysis of overload and low voltage should meet the following requirements. 1 For the power sending end system, in the case of no faults in the power transmission lines and step-up contact transformers, tripping due to faults, DC blocking, etc., the overload problem of power transmission lines or step-up transformers should be studied. 2 For the receiving end system, in the case of power supply line, step-down contact transformer or local power loss, etc., the overload problem of power supply line or step-down transformer should be studied. 3 For the intermediate connections and sections of power transmission, if the important lines of power transmission have no faults or trip due to faults, the overload problem of other lines in the same transmission section should be studied. 4.After the important components (lines, transformers) are disconnected, check whether the voltage level meets the requirements for stable operation. 3.6.2 Check the stability of the system under the operation mode specified in section 3.2 of this code and the fault type specified in section 3.3.The tentative stability analysis should consider the occurrence of metallic short circuit at the most unfavorable location, and the calculation time can be selected to be about 5s. 3.6.3 Dynamic stability analysis should be carried out when the connection between the power supply and the system is weak, the power grid runs in parallel through the weak connection line, there is a high-power periodic impact load, automatic adjustment measures such as rapid excitation adjustment are adopted, or system accidents are necessary. The calculation time of dynamic stability analysis can be selected as 20s or more. 3.6.4 Transient and dynamic voltage stability analysis can use transient stability and dynamic stability calculation programs. 3.6.5 In the case of large active power imbalance after power system failure, frequency stability analysis should be carried out. 3.7 Stability criterion 3.7.1 The thermal stability criteria of transformers and lines shall meet the following requirements. 1 The transformer load level should be limited to the specified overload capacity and duration of the transformer. 2 The power of the line should be limited within the allowable transmission capacity of the thermal stability of the line. The thermal stability limit of the line can be determined according to the cross-section, type, allowable temperature rise of the wire, and ambient temperature. 3.7.2 Transient stability criteria should include the following three aspects. 1 Power Angle Stability. After the system fails, the relative angle swing curves of any two units in the same AC system will show synchronous damping oscillation. 2.Voltage stability. After the fault is cleared, the busbar voltage of the grid hub substation can be restored to above 0.8pu, and the time for the busbar voltage to remain below 0.75pu shall not exceed 1.0s. 3.Stable frequency. After the measures of machine cutting and load shedding are taken, the system frequency does not collapse, and can return to the normal range without affecting the normal operation value of the large unit. The frequency range of normal operation can be 49.5Hz to 50.5Hz. 3.7.3 The dynamic stability criterion is that after a small or large accident disturbance, the relative power angle of the generator and the power of the transmission line are attenuated during the dynamic swing process, and the voltage and frequency can return to the allowable range.
