GB/T 50703-2011 English PDFUS$949.00 · In stock
Delivery: <= 7 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 50703-2011: Code for design of automaticity equipment for power system security Status: Valid
Basic dataStandard 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: 43,442 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---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.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. 4 Main control measures of safety automatic devices4.1 Removing the generator 4.1.1 On the premise of meeting the control requirements, the control object should be selected according to the order of hydropower unit, wind power unit and thermal power unit. 4.1.2 In principle, nuclear power units are not considered as control objects, but under the premise that removing other units cannot meet the system stability requirements and ensure the safety of nuclear reactors, nuclear power units can be removed. 4.1.3 Necessary margin should be considered when determining the cut-off amount. 4.2 Concentrated load shedding 4.2.1 In order to ensure the safe and stable operation of the power system, centralized load shedding can be realized through the safety and stability control device. 4.2.2 The load shedding device can cut off the low-voltage power supply line of the substation to realize load shedding. When selecting the load to be shed, the importance and effectiveness of the shed load should be considered comprehensively. 4.2.3 The setting of the load shedding station should be determined according to the amount of load to be shed and the distribution of the load, and a certain margin (about 20%) should be considered for the number of load shedding. 4.2.4 Measures should be taken to avoid automatic input of the removed load. 4.3 Control of reactive power compensation device 4.3.1 The forced compensation function of the controllable series compensation device of the transmission line is an effective means to improve the transient stability of the system, and it can be used as a synchronous stability control measure according to the needs of the power grid. 4.3.2 Cut off the shunt reactor or put in the shunt capacitor to prevent voltage drop; put in the shunt reactor or cut off the shunt capacitor to limit the excessive voltage. 4.4 Disconnection of power system and input of backup power supply 4.4.1 The disconnection of the power system should be carried out in a planned way at the preset disconnection point, and each part of the system after disconnection should have control measures to limit the frequency from being too high or too low. 4.4.2 When the system frequency drops abnormally, the standby units of the hydropower station and the storage power station can be started automatically to restore the system frequency. 4.5 DC Control 4.5.1 According to the needs of the power grid, by controlling the transmission power of the DC transmission system and blocking the operation of the DC poles, system stability damage and equipment overload can be prevented, and system overvoltage and frequency fluctuations can be limited. 4.5.2 The specific methods of DC control may include the following. 1 system frequency limit; 2 power or frequency modulation; 3 The DC power is urgently raised or lowered; 4 DC pole blocking. 4.5.3 DC control can be detected and executed by the DC control system, and can also receive commands sent by other devices.5 Configuration of safety automatic devices5.1 Configuration principles of safety automatic devices 5.1.1 Safety automatic devices include. safety and stability control device, automatic deloading device, over-frequency cut-off device, low-voltage control device, low-frequency and low-voltage load shedding device, backup power automatic input device, and automatic reclosing device. The configuration of safety automatic devices should be based on the conclusions of safety and stability calculations, and should be reasonably configured according to the grid structure, operating characteristics, communication channel conditions and other conditions. The analysis conclusions are consistent, and the technical and economic evaluation of the configuration scheme should be carried out. 5.1.2 The configuration and composition of safety automatic devices shall be in accordance with the current national standards "Guidelines for Safety and Stability of Power Systems" DL 755 and "Technical Guidelines for Safety and Stability of Power Systems" GB/T 26399, in accordance with the requirements for safe and stable operation of power systems The determination of the third-level standard shall adopt the following principles during implementation. 1 The premise is to ensure the reliability requirements of power system security and stability control, and at the same time, the effectiveness of power system security and stability control should be guaranteed. 2 Local control and layered partition control can be used. 3 The automatic safety devices of important stations shall be configured in dual configuration. 4 The device configuration should be simple, reliable and practical, and the connection with the relay protection device should be minimized. 5.1.3 Safety and stability control measures include DC modulation, machine cut-off, load shedding, de-loading, etc. The sequence of the above measures can be determined according to the project situation. Various stability control measures and control systems should be coordinated and coordinated, and the actions of safety automatic devices should be selective. 5.1.4 Safety automatic devices shall meet the following requirements. 1 The automatic safety device shall adopt a microcomputer, preferably a distributed device that has passed national appraisal, has mature experience, is simple, reliable, effective, and technologically advanced. 2 The original safety automatic device should be fully utilized. 3 The hardware of the selected device should have a certain degree of versatility, and the software should be modularized, scalable and have good system adaptability. 5.2 Safety automatic device configuration 5.2.1 When the type II accident disturbance listed in Table 3.3.2 occurs in the power system area under study (consider the type I accident disturbance listed in Table 3.3.2 under special circumstances), in the case of power system instability, Safety and stability control devices should be configured. By taking corresponding control measures to improve the stability of the power system, the accidents that destroy the stability of the power system are prevented, and the loss of part of the load is allowed at this time. The functions of commonly used safety and stability control devices are as follows. 1 For power delivery systems, control measures to reduce power output can usually be adopted. 2 For the receiving end system, control measures to reduce load demand can usually be adopted. 3 For DC transmission systems or systems equipped with series compensation devices, the safety and stability control device can send control commands to the DC control system or series compensation control system to realize DC power modulation and series compensation compensation. DC and series compensation control should be used in combination with other control measures. 5.2.2 In the area under study, according to the structure of the primary grid, for the connection sections that may run asynchronously, an out-of-synchronization decoupling device should be configured. When the synchronization is lost, the system will be disconnected to prevent the accident from expanding. 5.2.3 When the active power of the system suddenly becomes excessive and the frequency rises rapidly, an overfrequency cut-off device should be configured. The configuration scheme can remove units with a certain capacity in rounds according to different frequencies. 5.2.4 When the voltage of the local system drops to the allowable value due to insufficient reactive power, a low-voltage control device should be configured to take control measures to prevent the system voltage from collapsing and the scope of system accidents from expanding. Commonly used low voltage control measures should include the following. 1 Increase the reactive power output of the generator; 2 Quick input of capacitive reactive power compensation device; 3 Quick removal of inductive reactive power compensation device; 4 Quick shedding of partial loads. 5.2.5 In areas where the loss of part of the power supply causes frequency reduction and rapid voltage reduction may lead to system collapse, a low-frequency low-voltage load shedding device should be configured. According to the set value, the device removes a certain amount of load in rounds. 5.2.6 The factory and station buses that meet the following requirements should be equipped with automatic backup power supply devices. 1 Power plant power busbar and substation station power busbar with backup power supply; 2 The substation busbar powered by dual power sources and one of the power sources is often disconn...... |
