Fault processing method of public building energy supply system

Abstract

The invention provides a fault processing method for a public building energy supply system, and the method specifically comprises the steps: detecting the fault condition of the public building energy supply system, and obtaining the fault position and the corresponding fault type of the public building energy supply system; determining a target operation state of the public building energy supply system; obtaining load information before the fault condition of the public building energy supply system is detected, and setting a power limiting condition of fault isolation; and formulating a load intertripping scheme according to the power limiting condition, the corresponding fault type and a preset relay protection strategy, and performing fault isolation of the public building energy supply system. According to the invention, the corresponding power limiting condition can be set according to the specific operation state, and the power limitation is also taken as the basis for formulating the load intertripping scheme for fault processing, so that even if the public building energy supply system operates in different operation states, after the fault processing is carried out according to the formulated load intertripping scheme, the fault processing efficiency is improved. Power balance can be realized, and system stability is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of microgrid fault processing, and in particular to a fault processing method for a public building energy supply system. Background Art

[0002] For public buildings such as office buildings, shopping malls, and hospitals, their normal operation is highly dependent on the stability of the energy supply system. Once a public building energy supply system fails, it will directly affect the use of lighting, air conditioning, elevators and other equipment in the building, and then affect the normal work and life of the people in the building. In addition, public buildings are densely populated, and the failure of the energy supply system may cause a series of safety problems, such as fires caused by short circuits. Therefore, it is necessary to deal with the failure of the energy supply system of public buildings in a timely manner to ensure the normal operation and safety of public buildings.

[0003] Most of the existing fault handling methods for public building energy supply systems are based on the fact that the public building energy supply system is running in a grid-connected state. They can use the support and assistance of the power grid to handle faults more quickly, without considering the power balance problem of the public building energy supply system after the fault is handled. However, when a controller failure or other problems occur in the public building energy supply system, it may switch to an off-grid operation state. If the existing fault handling methods for public building energy supply systems are still used to remove faults in an off-grid operation state, it is easy to cause power imbalance in the public building energy supply system in an off-grid operation state, and the system stability of the public building energy supply system after the fault removal is completed is difficult to guarantee. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art that the fault handling of a public building energy supply system relies on the support and assistance of the power grid, is difficult to adapt to the fault handling scenario of the public building energy supply system in an off-grid operation state, is easy to cause the occurrence of power imbalance, and affects the system stability of the public building energy supply system. A fault handling method for a public building energy supply system is provided. Before performing fault handling, the operating state of the public building energy supply system when performing fault handling is determined according to the fault location and the fault type, so as to set corresponding power limitation conditions according to the specific operating state, and use the power limitation as the basis for formulating a load interlocking scheme for fault handling, so that even when the public building energy supply system is operating in different operating states, after the fault is handled according to the formulated load interlocking scheme, power balance can be achieved to ensure system stability.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] Troubleshooting methods for public building energy supply systems include:

[0007] Detect the fault conditions of the energy supply system of a public building, and obtain the fault location and corresponding fault type of the energy supply system of a public building;

[0008] Determine the target operating state of the public building energy supply system based on the fault location and the corresponding fault type;

[0009] Obtain load information before a fault in the energy supply system of a public building is detected, and set power limit conditions for fault isolation in combination with the corresponding target operating state;

[0010] A load shedding plan is formulated based on power limitation conditions, corresponding fault types and preset relay protection strategies, and fault isolation of the public building energy supply system is carried out according to the load shedding plan.

[0011] Furthermore, the determining of the target operating state of the public building energy supply system based on the fault location and the corresponding fault type includes:

[0012] Determine the fault impact range based on the fault location and the corresponding fault type, and collect the operating data of each fault-related device within the fault impact range before and after the fault;

[0013] Determine the loss load based on the operating data of each fault-related device before and after the fault, and calculate the fluctuation value of the system stability index;

[0014] The severity of the fault is evaluated based on the fault impact range, loss load and fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined based on the severity of the fault.

[0015] Furthermore, the fault severity is evaluated according to the fault impact range, the loss load and the fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined according to the fault severity, including:

[0016] Determine the equipment type and power supply area of ​​each fault-related equipment within the fault impact range, calculate the power supply impact area of ​​the fault impact range, determine the proportion of the power supply impact area in the total power supply area of ​​the public building energy supply system, and evaluate the severity of the fault impact range based on the proportion of the power supply impact area;

[0017] Obtain the total load of the public building energy supply system, determine the proportion of the lost load in the total load of the public building energy supply system, and evaluate the severity of the load loss according to the proportion of the lost load;

[0018] Match the fluctuation value of the system stability index with the preset fluctuation range, and evaluate the severity of the system stability fluctuation according to the matching result;

[0019] The evaluation results of the fault impact range, load loss and system stability fluctuation are weighted and summed to obtain the evaluation value of the fault severity;

[0020] comparing the evaluation value of the fault severity with a preset threshold;

[0021] If the evaluation value exceeds the preset threshold, the target operating state of the public building energy supply system is determined to be an off-grid operating state;

[0022] If the evaluation value does not exceed the preset threshold, the target operating state of the public building energy supply system is determined to be the grid-connected operating state.

[0023] Furthermore, the load information before the public building energy supply system fault is detected is obtained, and the power limit condition for fault isolation is set in combination with the corresponding target operating state, including:

[0024] When the target operating state is the off-grid operating state, the adjustable power source list and the upper limit value of load control are determined according to the load information before the failure of the public building energy supply system;

[0025] Determine the main power supply of the public building energy supply system and set the output power safety range of the main power supply;

[0026] The power limitation condition is set according to each adjustable load information in the adjustable load list, the load control upper limit value and the output power safety range of the main power supply.

[0027] Furthermore, the power limitation condition includes:

[0028] P 负荷总额 <P 调节电源(max) +P 主电源(max) ;

[0029] P 主电源(max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) ;

[0030] P 调节电源(max) +P 主电源(安全max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) +P 可切负荷总额 ;

[0031] P 主电源安全下限 <P 主电源当前输出 <P 主电源安全上限 ;

[0032] Among them, P 负荷总额 The total load of the public building energy supply system in operation; P 调节电源(max)P is the total output power of the regulated power supplies involved in the regulation of the adjustable power supply; 主电源(max) The total output power of the main power supply; P 主电源(安全max) The maximum total output power of the main power supply; P 可切负荷总额 The total amount of load that can be removed in the public building energy supply system; P 主电源安全下限 The output power safety lower limit of the main power supply, P 主电源当前输出 is the current output power of the main power supply, P 主电源安全上限 The safe upper limit of the output power of the main power supply.

[0033] Furthermore, the load shedding scheme is formulated according to the power limitation condition, the corresponding fault type and the preset relay protection strategy, and the fault isolation of the public building energy supply system is performed according to the load shedding scheme, including:

[0034] When a public building energy supply system fails, the corresponding relay protection strategy is automatically triggered according to the fault type, and load disconnection is triggered at the same time;

[0035] Obtaining load information before a fault condition of a public building energy supply system is detected, and classifying loads in the public building energy supply system;

[0036] Prioritize the removal of each type of load according to its importance and impact on system stability;

[0037] The loads involved in load shedding and the corresponding shedding sequence and shedding amount are determined according to the shedding priority and power limit conditions.

[0038] Furthermore, the method of formulating a load shedding scheme according to the power limitation condition, the corresponding fault type and the preset relay protection strategy, and isolating the fault of the public building energy supply system according to the load shedding scheme, further includes:

[0039] Fault isolation is performed according to the relay protection strategy, and load shedding is performed according to the shedding sequence and shedding amount specified in the load shedding plan;

[0040] Collect the output power of the main power supply in real time, and determine the power surplus or power shortage based on the output power of the main power supply;

[0041] The output power of the power source is adjusted among the loads participating in the load shedding according to the power surplus or power shortage, or the loads participating in the load shedding are adjusted.

[0042] Furthermore, the relay protection strategy includes busbar differential protection, line longitudinal differential protection and feeder protection.

[0043] The beneficial effects of the present invention are:

[0044] Before performing fault handling, the operating status of the public building energy supply system when performing fault handling is determined based on the fault location and fault type, so as to set the corresponding power limit conditions according to the specific operating status. The power limit is also used as the basis for formulating the load interlocking plan for fault handling, so that even if the public building energy supply system is operating in different operating states, after the fault is handled according to the formulated load interlocking plan, power balance can be achieved to ensure system stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of an energy management control structure of a public building energy supply system according to an embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of a process of the present invention;

[0047] Figure 3 The present invention is a feeder protection logic block diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0049] Example:

[0050] The energy management of public building energy supply systems mainly adopts a three-layer control structure, including local control and protection layer, coordination control and protection layer and station control layer. The station control layer is the optimization control and monitoring layer, such as Figure 1 shown.

[0051] Among them, the local control and protection layer includes local intelligent terminals such as energy storage intelligent terminals, wind turbine intelligent terminals, photovoltaic intelligent terminals, measurement and control devices, and main network incoming cabinets. The local intelligent terminals are installed on-site near distributed power sources and loads, and communicate with the coordinated control and protection layer through high-speed fiber optic networks.

[0052] The coordinated control and protection layer includes the system controller device of the public building energy supply system. The system controller device quickly communicates with the local terminal through the GOOSE / SV process layer network based on the IEC61850 standard to obtain the sampling data synchronized with the whole system. By configuring the feeder quick-break protection, busbar differential protection, and line longitudinal differential protection, it can quickly locate and isolate faults in the entire public building energy supply system network, and realize rapid protection with an action speed of less than 15ms.

[0053] However, the above-mentioned rapid protection is based on the normal operation of the system controller device, the operation of the public building energy supply system in the grid-connected operation state, and the fault handling is assisted by the power grid.

[0054] When the system controller device fails, or the severity of the failure is too high, causing the public building energy supply system to switch to off-grid operation, a load switching plan can be formulated to set and adjust the operating mode and control parameters of each adjustable power source, adjustable load, etc., so as to maintain the power of the public building energy supply system within the allowable range and meet the grid-connected operation requirements of the local intelligent terminal, thereby ensuring the safe and stable operation of the public building energy supply system.

[0055] In addition, the system controller device also provides a fault recorder based on the entire station with 256 points per cycle, providing more comprehensive fault information than traditional fault recorders, and can perform more comprehensive fault analysis. It is also connected to an external graphic display terminal, which can be monitored by on-site engineers to debug the function through the debugging interface.

[0056] The optimization control and monitoring layer is composed of the background monitoring system of the public building energy supply system, data gateway, vertical encryption and other data transmission devices. The background monitoring system adopts an advanced monitoring system platform, which integrates the monitoring, control, management and simulation training of equipment in the field of industrial control. It is independent of each other in terms of functions. Through flexible configuration and configuration, it can meet the requirements of automatic control management in various fields. Among them, the monitoring host of the background monitoring system adopts a dual-machine hot standby redundant configuration to realize real-time information monitoring, historical information storage, wind and solar forecasting, economic operation control, advanced energy management and report statistics. The background monitoring system is also equipped with a Web publishing interface, an on-site visit display interface and an operator interface to support the real-time display of monitoring data.

[0057] Based on the energy management control structure of the public building energy supply system, a fault handling method for the public building energy supply system is proposed. Figure 2 As shown, including:

[0058] Detect the fault conditions of the energy supply system of a public building, and obtain the fault location and corresponding fault type of the energy supply system of a public building;

[0059] Determine the target operating state of the public building energy supply system based on the fault location and the corresponding fault type;

[0060] Obtain load information before a fault in the energy supply system of a public building is detected, and set power limit conditions for fault isolation in combination with the corresponding target operating state;

[0061] A load shedding plan is formulated based on power limitation conditions, corresponding fault types and preset relay protection strategies, and fault isolation of the public building energy supply system is carried out according to the load shedding plan.

[0062] When a public building energy supply system fails, the following principles must be followed to remove the fault and ensure rapid power supply restoration:

[0063] 1. Reliably and quickly cut off the fault line;

[0064] 2. Avoid cutting off fault-free power supplies and loads, and minimize the scope of power outages and the number of lost power points;

[0065] 3. If the system is connected to the grid after the fault is cleared, the power balance of the public building energy supply system does not need to be considered;

[0066] 4. If the system is off-grid after the fault is cleared, it is necessary to consider cutting off part of the load or power supply based on power balance to ensure that the main power supply (lithium battery pack + PCS) operates within a safe range to ensure system stability.

[0067] Under the constraints of the above principles, the fault condition of the public building energy supply system is first detected according to the system controller device, and the fault location and corresponding fault type of the public building energy supply system are obtained, so as to determine the target operating state of the public building energy supply system when the fault is removed according to the fault condition.

[0068] After determining the target operating state of the public building energy supply system, it can be determined whether it is necessary to refer to the power balance of the public building system when performing fault handling.

[0069] If the public building energy supply system is operating in a grid-connected state, the power grid will bear the power fluctuations caused by fault isolation. When formulating the load switching plan for the public building energy supply system, there is no need to add corresponding power limits.

[0070] If the public building energy supply system operates in an off-grid operating state, due to the limited regulation capacity of the equipment, power fluctuations are likely to occur when load shedding and fault isolation are carried out in coordination with relay protection action. This power fluctuation needs to be absorbed by the public building energy supply system itself. Therefore, in order to avoid the impact of this power fluctuation on the operation of the public building energy supply system, when formulating the load shedding plan, power balance will be used as the power limitation condition of the load shedding plan to ensure the stability of the public building energy supply system.

[0071] The determining of the target operating state of the public building energy supply system based on the fault location and the corresponding fault type includes:

[0072] Determine the fault impact range based on the fault location and the corresponding fault type, and collect the operating data of each fault-related device within the fault impact range before and after the fault;

[0073] Determine the loss load based on the operating data of each fault-related device before and after the fault, and calculate the fluctuation value of the system stability index;

[0074] The severity of the fault is evaluated based on the fault impact range, loss load and fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined based on the severity of the fault.

[0075] Except for the specific fault type of system controller device failure, when the severity of other faults is too high, in order to avoid affecting the operation of the power grid, it will actively switch to the off-grid operation state.

[0076] The severity of a fault is usually assessed from three aspects: the scope of the fault, the amount of load lost, and the impact on system stability.

[0077] Therefore, the fault location and the corresponding fault type are determined according to the system controller device, thereby determining the fault impact range, and extracting each device within the fault impact range as a fault-associated device, and obtaining the specific loss load according to the operating status changes of each device.

[0078] At the same time, according to the operating data of each fault-related equipment before and after the fault, the system stability index values ​​such as voltage, frequency and power flow before and after the fault are determined, and the fluctuation value of the system stability index is determined.

[0079] The fault severity is evaluated according to the fault impact range, the loss load and the fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined according to the fault severity, including:

[0080] Determine the equipment type and power supply area of ​​each fault-related equipment within the fault impact range, calculate the power supply impact area of ​​the fault impact range, determine the proportion of the power supply impact area in the total power supply area of ​​the public building energy supply system, and evaluate the severity of the fault impact range based on the proportion of the power supply impact area;

[0081] Obtain the total load of the public building energy supply system, determine the proportion of the lost load in the total load of the public building energy supply system, and evaluate the severity of the load loss according to the proportion of the lost load;

[0082] Match the fluctuation value of the system stability index with the preset fluctuation range, and evaluate the severity of the system stability fluctuation according to the matching result;

[0083] The evaluation results of the fault impact range, load loss and system stability fluctuation are weighted and summed to obtain the evaluation value of the fault severity;

[0084] comparing the evaluation value of the fault severity with a preset threshold;

[0085] If the evaluation value exceeds the preset threshold, the target operating state of the public building energy supply system is determined to be an off-grid operating state;

[0086] If the evaluation value does not exceed the preset threshold, the target operating state of the public building energy supply system is determined to be the grid-connected operating state.

[0087] Among them, the fault impact range is mainly defined by the power supply abnormality range caused by the fault. In order to quantify it into a specific indicator value, the equipment type and power supply area of ​​each fault-related equipment within the fault impact range are determined, the proportion of the power supply impact area in the total power supply area is determined, and the impact of this fault on the power supply area of ​​the public building energy supply system is determined. The larger the proportion of the power supply impact area, the higher the severity of the fault impact range.

[0088] Similarly, the severity of load loss is quantified by the proportion of lost load in the total load. The greater the proportion of lost load, the greater the severity of the load loss. For example, when the proportion of lost load is less than 5%, the severity is low. When the proportion of lost load is between 5% and 20%, the severity is medium. When the lost load exceeds 20%, the severity is high.

[0089] Secondly, the system stability index fluctuation value is matched with the preset fluctuation range to quantify the severity of the system stability fluctuation.

[0090] After determining the specific severity of the three dimensions, assign values ​​according to the corresponding severity, and then obtain the evaluation value of the fault severity through weighted summation.

[0091] Finally, by comparing the fault severity assessment value with the preset threshold, it is determined whether the fault is serious enough to affect the operation of the power grid and whether it is necessary to switch to off-grid operation.

[0092] The method of obtaining load information before a fault in the energy supply system of a public building is detected and setting a power limit condition for fault isolation in combination with a corresponding target operating state includes:

[0093] When the target operating state is the off-grid operating state, the adjustable power source list and the upper limit value of load control are determined according to the load information before the failure of the public building energy supply system;

[0094] Determine the main power supply of the public building energy supply system and set the output power safety range of the main power supply;

[0095] The power limitation condition is set according to each adjustable load information in the adjustable load list, the load control upper limit value and the output power safety range of the main power supply.

[0096] For public building energy supply systems in off-grid operation, in order to ensure that the public building energy supply system can operate off-grid after the grid-connected line is disconnected, it is also necessary to adjust the grid-connected line exchange power to the minimum. After the fault is removed, it is necessary to keep the system back to stable operation by cutting off part of the load and power supply, that is, adjust the main power supply output power to a safe range.

[0097] However, due to the offline operation at this time, the adjustable load information and load control upper limit in the public building energy supply system are limited by equipment settings. When performing load / power supply switching to adjust the power situation, the actual equipment limitations need to be taken into account.

[0098] Therefore, the following power limit conditions are specifically set:

[0099] P 负荷总额 <P 调节电源(max) +P 主电源(max) ;

[0100] P 主电源(max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) ;

[0101] P 调节电源(max) +P 主电源(安全max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) +P 可切负荷总额 ;

[0102] P 主电源安全下限 <P 主电源当前输出 <P 主电源安全上限 ;

[0103] Among them, P 负荷总额 The total load of the public building energy supply system in operation; P 调节电源(max) P is the total output power of the regulated power supplies involved in the regulation of the adjustable power supply; 主电源(max) The total output power of the main power supply; P 主电源(安全max) The maximum total output power of the main power supply; P 可切负荷总额 The total amount of load that can be removed in the public building energy supply system; P 主电源安全下限 The output power safety lower limit of the main power supply, P 主电源当前输出 is the current output power of the main power supply, P 主电源安全上限 The safe upper limit of the output power of the main power supply.

[0104] The load shedding scheme is formulated according to the power limitation conditions, the corresponding fault type and the preset relay protection strategy, and the fault isolation of the public building energy supply system is performed according to the load shedding scheme, including:

[0105] When a public building energy supply system fails, the corresponding relay protection strategy is automatically triggered according to the fault type, and load disconnection is triggered at the same time;

[0106] Obtaining load information before a fault condition of a public building energy supply system is detected, and classifying loads in the public building energy supply system;

[0107] Prioritize the removal of each type of load according to its importance and impact on system stability;

[0108] The loads involved in load shedding and the corresponding shedding sequence and shedding amount are determined according to the shedding priority and power limit conditions.

[0109] When formulating a load shedding plan, some loads that are less important and have less impact on system stability can be cut off first, so as to achieve the goal of reducing the impact on system stability while adjusting system power.

[0110] The amount of joint cutting can be calculated through the fault conditions detected by the system controller device to determine the amount of compensation or cutting required.

[0111] The switching order is then selected based on the shedding priority, and the switching amount of each load participating in the load switching is selected under the power limitation condition.

[0112] The preset relay protection strategies include busbar differential protection, line longitudinal differential protection and feeder protection.

[0113] Among them, since the main connection of the public building energy supply system is a double bus, bus differential protection is configured to achieve quick-break protection for bus faults, and the protection action area is fixed without coordination problems. The bus protection has high sensitivity and is less affected by load current. The differential current setting is 0.2IN, which can ensure that the protection sensitivity coefficient is greater than 1.5.

[0114] In this embodiment, ratio differential is used to perform bus differential protection. The ratio differential includes a large differential element and a small differential element, and the differential formulas thereof are the same.

[0115] The large difference element of the proportional differential element has two fixed values: the large difference high value is 0.5, the large difference low value is 0.3, and the small difference is fixed at 0.5. When the large difference and the small difference act at the same time, the proportional differential element acts.

[0116] The compound ratio differential action equation is as follows:

[0117]

[0118] Among them, I d is the phase differential current, K r is the fixed value of the compound ratio coefficient, I dsetis the starting current setting of differential protection, I r is the braking current.

[0119] However, when a busbar outgoing line fails, the voltage transformer CT that assists in the busbar differential protection judgment may be saturated. In order to prevent the busbar differential protection from malfunctioning due to CT saturation when an out-of-zone fault occurs, additional CT saturation identification measures are formulated in the busbar differential protection.

[0120] There is a linear transition zone at the beginning of the out-of-zone fault and near the zero point of the circuit current. Therefore, the differential current exceeding the limit is not synchronized with the actual fault time, but there is a lag. When a busbar out-of-zone fault occurs, a linear transition zone of 3 to 5ms after the beginning of the fault can be guaranteed, and the differential current is zero in this transition zone; for a busbar fault within the zone, the differential current reflects the fault current, and the current exceeding the limit is synchronized with the actual fault time. Therefore, the saturation situation can be identified based on whether the differential current exceeding the limit is synchronized with the actual fault time, thereby avoiding the occurrence of false operation of the busbar differential protection.

[0121] The line longitudinal differential protection setting value is set according to the unbalanced current of the line, taking 0.1IN to ensure that the sensitivity is greater than 1.5. The specific protection principle is as follows:

[0122] The positive polarity end of the CT is specified to point to the bus side, and the reference direction of the current is the positive direction from the bus to the line. The differential current is defined as The braking current is in, and are the current vectors on both sides respectively.

[0123] The line longitudinal differential protection is specifically performed by the steady-state section I differential relay and the steady-state section II differential relay. Specifically, the action equation of the steady-state section I differential relay is:

[0124]

[0125] Among them, I H It is 1.5 times the differential current constant, and φ is the three phases A, B, and C.

[0126] The action equation of the steady-state stage II differential relay is:

[0127]

[0128] Among them, I L is the differential current constant.

[0129] And the steady-state stage II differential relay will operate after a 25ms delay.

[0130] Since the public building energy supply system has multiple distributed power sources and the power lines have double-sided power sources, in this embodiment, the feeder is mainly protected by directional re-pressure over-current speed-off protection, and the protection is adjusted according to the maximum load of the line or the power output to ensure that the sensitivity is greater than 1.2.

[0131] The feeder protection logic block diagram in this embodiment is as follows: Figure 3 As shown, Figure 3 middle, I set is the quick-break setting value, U set is the low voltage setting value, T set Set a value for time.

[0132] The method further comprises: formulating a load shedding scheme according to the power limitation conditions, the corresponding fault type and the preset relay protection strategy, and isolating the fault of the public building energy supply system according to the load shedding scheme,

[0133] Fault isolation is performed according to the relay protection strategy, and load shedding is performed according to the shedding sequence and shedding amount specified in the load shedding plan;

[0134] Collect the output power of the main power supply in real time, and determine the power surplus or power shortage based on the output power of the main power supply;

[0135] The output power of the power source is adjusted among the loads participating in the load shedding according to the power surplus or power shortage, or the loads participating in the load shedding are adjusted.

[0136] During the execution of fault handling, the execution effect may not meet expectations, resulting in fluctuations in the output power of the main power supply. Therefore, during the execution of the load switching plan, the output power of the main power supply is collected in real time, and the power surplus or power shortage is determined based on the output power of the main power supply.

[0137] The power surplus is P 功率盈余 =P 主电源安全下限 -P 主电源当前输出 , the power deficit is P 功率缺额 =P 主电源当前输出 -P 主电源安全上限 .

[0138] Then determine specific adjustment measures based on power surplus or power shortage, specifically:

[0139] In P 主电源当前输出 <P 主电源安全下限 When the power surplus is P 功率盈余 =P 主电源正常下限 -P 主电源当前输出 ; It is necessary to reduce the output power of the regulated power supply or cut off part of the power supply. The power supply cutoff target is P after cutoff 主电源当前输出 +P 切除的不可调节电源 >P主电源正常下限 , and meet the minimum unregulated power cutoff.

[0140] In P 主电源当前输出 >P 主电源安全上限 When the power shortage is P 功率缺额 =P 主电源当前输出 -P 主电源安全上限 , it is necessary to increase the output power of the regulated power supply or cut off part of the load.

[0141] In this embodiment, the regulated power supply is used as a P / Q operating power supply.

[0142] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for troubleshooting a public building energy supply system, characterized in that: include: Detect the fault conditions of the energy supply system of a public building, and obtain the fault location and corresponding fault type of the energy supply system of a public building; Determine the target operating state of the public building energy supply system based on the fault location and the corresponding fault type; Obtain load information before a fault in the energy supply system of a public building is detected, and set power limit conditions for fault isolation in combination with the corresponding target operating state; A load shedding plan is formulated based on power limitation conditions, corresponding fault types and preset relay protection strategies, and fault isolation of the public building energy supply system is carried out according to the load shedding plan.

2. The method for troubleshooting a public building energy supply system according to claim 1, characterized in that: The determining of the target operating state of the public building energy supply system based on the fault location and the corresponding fault type includes: Determine the fault impact range based on the fault location and the corresponding fault type, and collect the operating data of each fault-related device within the fault impact range before and after the fault; Determine the loss load based on the operating data of each fault-related device before and after the fault, and calculate the fluctuation value of the system stability index; The severity of the fault is evaluated based on the fault impact range, loss load and fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined based on the severity of the fault.

3. The method for troubleshooting a public building energy supply system according to claim 2, characterized in that: The fault severity is evaluated according to the fault impact range, the loss load and the fluctuation value of the system stability index, and the target operating state of the public building energy supply system is determined according to the fault severity, including determining the equipment type and the power supply area to which each fault-related equipment within the fault impact range belongs, calculating the power supply impact area of ​​the fault impact range, determining the proportion of the power supply impact area in the total power supply area of ​​the public building energy supply system, and evaluating the severity of the fault impact range according to the proportion of the power supply impact area; Obtain the total load of the public building energy supply system, determine the proportion of the lost load in the total load of the public building energy supply system, and evaluate the severity of the load loss according to the proportion of the lost load; Match the fluctuation value of the system stability index with the preset fluctuation range, and evaluate the severity of the system stability fluctuation according to the matching result; The evaluation results of the fault impact range, load loss and system stability fluctuation are weighted and summed to obtain the evaluation value of the fault severity; comparing the evaluation value of the fault severity with a preset threshold; If the evaluation value exceeds the preset threshold, the target operating state of the public building energy supply system is determined to be an off-grid operating state; If the evaluation value does not exceed the preset threshold, the target operating state of the public building energy supply system is determined to be the grid-connected operating state.

4. The method for troubleshooting a public building energy supply system according to claim 1, characterized in that: The method of obtaining load information before a fault in the energy supply system of a public building is detected and setting a power limit condition for fault isolation in combination with a corresponding target operating state includes: When the target operating state is the off-grid operating state, the adjustable power source list and the upper limit value of load control are determined according to the load information before the failure of the public building energy supply system; Determine the main power supply of the public building energy supply system and set the output power safety range of the main power supply; The power limitation condition is set according to each adjustable load information in the adjustable load list, the load control upper limit value and the output power safety range of the main power supply.

5. The method for troubleshooting a public building energy supply system according to claim 4, characterized in that: The power limitation conditions include: P 负荷总额 <P 调节电源(max) +P 主电源(max) ; P 主电源(max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) ; P 调节电源(max) +P 主电源(安全max) <P 负荷总额 <P 调节电源(max) +P 主电源(安全max) +P 可切负荷总额 ; P 主电源安全下限 <P 主电源当前输出 <P 主电源安全上限 ; Among them, P 负荷总额 The total load of the public building energy supply system in operation; P 调节电源(max) P is the total output power of the regulated power supplies involved in the regulation of the adjustable power supply; 主电源(max) The total output power of the main power supply; P 主电源(安全max) The maximum total output power of the main power supply; P 可切负荷总额 The total amount of load that can be removed in the public building energy supply system; P 主电源安全下限 The output power safety lower limit of the main power supply, P 主电源当前输出 is the current output power of the main power supply, P 主电源安全上限 The safe upper limit of the output power of the main power supply.

6. The method for troubleshooting a public building energy supply system according to claim 1, characterized in that: The load shedding scheme is formulated according to the power limitation conditions, the corresponding fault type and the preset relay protection strategy, and the fault isolation of the public building energy supply system is carried out according to the load shedding scheme. Including, when the public building energy supply system fails, the corresponding relay protection strategy is automatically triggered according to the fault type, and the load switching is triggered at the same time; Obtaining load information before a fault condition of a public building energy supply system is detected, and classifying loads in the public building energy supply system; Prioritize the removal of each type of load according to its importance and impact on system stability; The loads involved in load shedding and the corresponding shedding sequence and shedding amount are determined according to the shedding priority and power limit conditions.

7. The method for troubleshooting a public building energy supply system according to claim 6, characterized in that: The method further comprises formulating a load shedding scheme according to the power limit condition, the corresponding fault type and the preset relay protection strategy, and isolating the fault of the public building energy supply system according to the load shedding scheme, and isolating the fault according to the relay protection strategy, and performing load shedding according to the shedding sequence and shedding amount formulated in the load shedding scheme; Collect the output power of the main power supply in real time, and determine the power surplus or power shortage based on the output power of the main power supply; The output power of the power source is adjusted among the loads participating in the load shedding according to the power surplus or power shortage, or the loads participating in the load shedding are adjusted.

8. The method for troubleshooting a public building energy supply system according to claim 1, characterized in that: The relay protection strategy includes busbar differential protection, line longitudinal differential protection and feeder protection.

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