An arc light protection system for use in a power plant

Abstract

The application provides an arc light protection system applied to a power station, which comprises a master control system and a power supply module, two current units, a first arc light unit, a second arc light unit and a third arc light unit connected with the master control system, a bus of the power station comprises a first bus, a second bus and a sectional bus, a power supply loop on the first bus is provided with a first circuit breaker, the first bus and the sectional bus are provided with a second circuit breaker, and a power supply loop on the second bus is provided with a third circuit breaker; the arc light protection system applied to the power station simultaneously adopts arc light and current double criteria to prevent misjudgment from leading to large-scale power failure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of arc light protection device, and particularly relates to an arc light protection system applied to a power station. BACKGROUND

[0002] When the voltage between two electrodes is raised, the positive and negative ions in the air near the electrodes are accelerated by the electric field, and new ions are generated by collision with other air molecules during movement. This phenomenon of a large number of ions increasing is called ionization. At the same time, the air is ionized, and the temperature rises sharply to generate an arc. This discharge is called arc discharge. Once arc discharge occurs, a low voltage is generally not needed between the discharge gap, which belongs to low-voltage large-current discharge. The conditions for arc discharge are small gap and large current. According to the current occurring at different positions, it can be divided into the following three types: arc discharge between charged conductors, arc between charged conductors and the ground, and surface discharge (creepage) on the surface of insulators. Arc light energy is huge and has a surprising destructive power, which can cause equipment damage and damage to the entire power station. The recovery time of power supply after an accident is long, and even personnel casualties may occur. Therefore, there is an urgent need for a stable and reliable arc light protection system. SUMMARY

[0003] In view of the above technical problems, the present application provides an arc light protection system applied to a power station. The arc light protection system comprises a main control system and a power module, a first current unit, a second current unit, a first arc unit, a second arc unit and a third arc unit connected with the main control system. The bus of the power station comprises a first bus section, a second bus section and a sectional bus. The power circuit on the first bus section is provided with a first circuit breaker. The second circuit breaker is arranged between the first bus section and the sectional bus. The power circuit on the second bus section is provided with a third circuit breaker.

[0004] The main control system protects at least one switch cabinet of the power station. One end of the first current unit and the second current unit is directly connected with the main control system through an optical fiber and a data line. The other end of the first current unit and the second current unit is connected with a first current transformer and a second current transformer respectively. The first current transformer is used for collecting the power line current of the first bus section. The second current transformer is used for collecting the power line current of the second bus section. The first arc unit is connected with the main control system through a data line and an optical fiber. The second arc unit is connected with the main control system through an optical fiber and connected with the first arc unit through a data line. The third arc unit is connected with the second arc unit through a data line and an optical fiber. The first arc unit and the third arc unit are connected with a plurality of arc detection units through an optical fiber. The second arc unit is connected with a plurality of arc detection units through an optical fiber. The main control system is further connected with a plurality of arc detection units through an optical fiber. All the arc detection units are installed in the bus room and the circuit breaker room.

[0005] The main control system outputs a trip signal to the first circuit breaker, the second circuit breaker or the third circuit breaker according to the received arc light and current signals.

[0006] Further, the arc light protection system further comprises two groups of auxiliary protection systems, each of which comprises a plurality of auxiliary main control units, the auxiliary main control units are connected with auxiliary arc light detection units, the auxiliary arc light detection units are arranged in the cable chamber, a section of bus and a section of bus are respectively provided with auxiliary circuit breakers between the electrical equipment in the cable chamber in the two groups of protection systems, the auxiliary arc light detection units send the collected arc light to the auxiliary main control units, the auxiliary main control units output a trip signal to the auxiliary circuit breakers according to the received arc light, and preferably, the auxiliary main control units are connected with the main control system.

[0007] Further, the main control system further comprises a trip control circuit, which realizes by the following steps:

[0008] Collecting the alarm instructions sent by the section of bus and the section of bus, the mutual exclusion flag removing the alarm instructions on the section of bus, judging whether arc light alarm and current alarm occur on the section of bus at the same time, if yes, sending trip instructions to the first circuit breaker, the second circuit breaker and the relay connected with the second circuit breaker trip loop at the same time;

[0009] The mutual exclusion flag removes the alarm instructions on the section of bus, and judges whether arc light alarm and current alarm occur on the section of bus at the same time, if yes, sends trip instructions to the second circuit breaker, the third circuit breaker, the relay connected with the second circuit breaker loop and the relay connected with the third circuit breaker loop at the same time;

[0010] Judging whether arc light alarm and current alarm occur on the section of bus and the section of bus respectively, if yes, sending trip instructions to the second circuit breaker and the relay connected with the second circuit breaker loop at the same time;

[0011] Counting the number x of times that the second circuit breaker and the relay connected with the second circuit breaker loop receive trip instructions, setting the second circuit breaker and the relay connected with the second circuit breaker loop to be closed Y seconds after the fault is eliminated, Y=y+(x-1)a, wherein Y represents the recovery time after the fault is eliminated, a represents the time extended each time, x represents the number of times, x is a positive integer, and a and y are constants; the fault elimination means that the section of bus and the section of bus stop arc light alarm and current alarm, or the section of bus and the section of bus only produce arc light alarm or current alarm.

[0012] Further, the electrical equipment comprises a power distribution device and a standby transformer, the power distribution device and the standby transformer are connected with a plurality of loads, the standby transformer is connected with all the loads, and the arc light protection system further comprises a standby circuit, which realizes by the following steps:

[0013] The standby transformer and each load are in a tripped state;

[0014] The main control system determines whether the auxiliary circuit breaker between any power distribution device and one or two busbars has tripped. If it has tripped, it sends a command to connect the load connected to the corresponding power distribution device to the standby transformer.

[0015] The main control system determines whether the secondary circuit breaker has recovered. If it has, the standby transformer is disconnected from the load again, and the connection between the corresponding load and the power distribution device is restored.

[0016] Furthermore, the arc flash protection system includes a dual-criteria circuit for arc flash current; the dual-criteria circuit for arc flash current is implemented by the following steps:

[0017] The main control system or arc light unit receives the arc light sent by the arc light detection unit, compares the arc light with the arc light threshold, and sends an arc light alarm to the main control system when the arc light is greater than the arc light threshold.

[0018] The main control system receives the current signal sent by the power supply unit, converts the current signal into a current and compares it with the current threshold. When the current is greater than the current threshold, a current alarm is sent to the main control system.

[0019] Furthermore, the arc flash protection system also includes a temperature probe connected to the main control module. The temperature probe mainly includes a fiber optic temperature probe and / or a distributed fiber optic linear temperature detector. The temperature probe is connected to the main control system through the arc flash unit. Optical signals are transmitted between the arc flash unit and the temperature probe through optical fiber. Optical signals are transmitted between the arc flash unit and the arc flash detection unit through temperature-sensitive optical fiber. The temperature probe is installed in the busbar room and / or cable room and / or circuit breaker room.

[0020] Furthermore, temperature and humidity probes are also installed in the cable room and / or the circuit breaker room, and the arc flash protection system also includes a humidity criterion circuit, which is implemented through the following steps:

[0021] Collect humidity signals H from each sampling point, and compare all current humidity signals H with the humidity threshold H. 阈 Compare the sizes when H ≥ H 阈 When H < H, proceed to step S2. 阈 If so, no action is taken;

[0022] Determine if the current position H ≥ H 阈 The duration n is calculated, and n is compared with the number of days threshold n. 阈 The size, if n≥n 阈 If n < n 阈 If so, no action will be taken.

[0023] Further, the cable room and / or the cable room and / or the circuit breaker room are simultaneously provided with an arc light detection unit and a temperature and humidity probe, and the protection system further comprises an arc light and humidity double criterion circuit, which is realized by the following steps:

[0024] S1: Collect the arc light of each sampling point in the cable room, and determine whether the arc light exceeds the arc light threshold value; if yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step S2;

[0025] S2: Collect the humidity signal of each sampling point in the cable room, and determine whether the humidity exceeds the humidity threshold value; if yes, adjust the temperature threshold value downward.

[0026] Further, the cable room and / or the cable room and / or the circuit breaker room are simultaneously provided with a voltage probe and a temperature and humidity probe, and the protection system further comprises a voltage and humidity double criterion circuit, which is realized by the following steps:

[0027] (1) Collect the voltage signal of each sampling point in the cable room, and determine whether the voltage signal exceeds the voltage threshold value; if yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step (2);

[0028] Collect the humidity signal of each sampling point in the cable room, and determine whether the humidity exceeds the humidity threshold value; if yes, adjust the temperature threshold value downward, and proceed to step (1).

[0029] Further, the cable room and / or the cable room and / or the circuit breaker room are simultaneously provided with a voltage probe and a temperature probe, and the arc light protection system further comprises a voltage and temperature double criterion circuit, which is realized by the following steps:

[0030] a. Collect the voltage signal of each sampling point in the cable room, and determine whether the voltage exceeds the voltage threshold value; if yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step b;

[0031] b. Then collect the temperature signal of each sampling point in the cable room, and determine whether the temperature exceeds the temperature threshold value; if yes, adjust the arc light threshold value downward.

[0032] The application also provides the application of the arc light protection system applied to a nuclear power plant in a pumped storage power station and a hydropower station.

[0033] The beneficial effects of the application are as follows:

[0034] The arc light protection system applied to a power station provided by the application simultaneously adopts arc light and current double criteria to send a trip instruction to a circuit breaker when an arc light occurs in the power station, which can safely and quickly trip and cut off the arc light, protect the operating personnel from being injured, reduce the degree of property loss, and prevent misjudgment from causing large-scale power outage. Attached Figure Description

[0035] Figure 1 This is a configuration diagram of an arc flash protection system used in power plants.

[0036] Figure 2 This is a schematic diagram of the arc light unit interface;

[0037] Figure 3 This is a schematic diagram of the fiber optic connection port for the arc unit;

[0038] Figure 4 This is a wiring diagram for an arc flash protection system used in power plants. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and the following embodiments.

[0040] In some embodiments, such as Figure 1 As shown, an arc flash protection system for power plants is provided. The arc flash protection system includes a main control system and a power module, a first current unit, a second current unit, a first arc flash unit, a second arc flash unit, and a third arc flash unit connected to the main control system. The power plant's busbar includes a first busbar, a second busbar, and a segmented busbar. The power supply circuit on the first busbar is equipped with a first circuit breaker, a second circuit breaker is installed between the first busbar and the segmented busbar, and the power supply circuit on the second busbar is equipped with a third circuit breaker.

[0041] The main control system protects at least one switchgear of the power station. The first current unit and the second current unit are directly connected to the main control system at one end via optical fiber and data line, and the other end is connected to a first current transformer and a second current transformer, respectively. The first current transformer is used to collect the incoming current of a section of bus power supply, and the second current transformer is used to collect the incoming current of two sections of bus power supply. The first arc light unit is connected to the main control system via data line and optical fiber. The second arc light unit is connected to the main control system via optical fiber and to the first arc light unit via data line. The third arc light unit is connected to the second arc light unit via data line and optical fiber. Both the first and third arc light units are connected to several arc light detection units via optical fiber. The second arc light unit is connected to several arc light detection units via optical fiber. The main control system is also connected to several arc light detection units via optical fiber. All arc light detection units are installed in the bus compartment and the circuit breaker compartment.

[0042] Based on the received arc and current signals, the main control system outputs a trip signal to the first circuit breaker, the second circuit breaker, or the third circuit breaker.

[0043] This embodiment reduces the incidence of misjudgment by setting dual criteria of arc light and current.

[0044] In certain embodiments, the analog input of the master control system is as follows: 2 groups of 3-way (a total of 6-way) current collection (sampling range 0.1 In-20 In), 1-way zero sequence current (1A / 5A adaptive, sampling range 0.1 In-8 In), 1-way zero sequence voltage (sampling range 0-3 In), a total of 8-way analog signal input;

[0045] Arc light signal input: 16-way arc light signal input, 1-way remote (remote control signal input) + 4-way arc light cascade input (unit input);

[0046] In certain embodiments, the trip and signal outlet is a 10-way relay outlet (default),

[0047] In certain embodiments, the electronic outlet replaces the outlet board, the signal outlet needs to be manually reset, and the 10-way relay can specify the specific outlet of the protection, signal, blocking spare self-throwing, circuit breaker failure, etc. function through the software trip matrix table (a function can have a maximum of 10-way simultaneous output);

[0048] In certain embodiments, the working power supply of the master control system is 85V-265V;

[0049] In certain embodiments, the communication of the master control system includes 2 RJ45 interfaces (Ethernet communication interface and background communication), 1 RS485 terminal and background communication, and 1 RS485 and unit communication;

[0050] In certain embodiments, the master control system includes 1 IRIG-B code time synchronization;

[0051] In certain embodiments, the master control system can read the light intensity.

[0052] In certain embodiments, the master control software includes the following modules: arc light single criterion protection module, current arc light double criterion protection module, ground arc light protection module, circuit breaker failure protection module, trip logic module, output outlet module, device self-checking module, trip alarm information cabinet number selection module, fault alarm detailed record query module, fault recording module, B code time synchronization module, monitoring system communication and unit communication module.

[0053] In certain embodiments, the arc light unit serves as an arc light signal expansion of the master control, provides a trip signal to the master control, and can receive a level signal uploaded to the master control by the next level arc light unit, and the setting value and address are set through the master control using RS485 communication (address range 1-250);

[0054] In certain embodiments, the arc light unit includes 1 RS485 interface, 1 12V power supply port, 1 double-color lamp, 1 reset key, 10-way arc light signal input, 1 cascade input optical fiber port, and 1 cascade output optical fiber port.

[0055] In some embodiments, the arc unit includes the following modules: arc unit criterion protection module, cascaded input and output module, fixed value and address setting module, and communication alarm information uploading module.

[0056] In some embodiments, the current unit is used as a master control overcurrent signal expansion and separately for feeder cabinet, and can receive the level signal uploaded by the next level current unit to the master control, and the address (address range 1-250), current setting value and trip logic can be modified by the master control through RS485 communication.

[0057] In some embodiments, the current unit includes a set of 3-channel current input module (sampling range: 0.5In-20In), 2, 3-channel arc input module, 3-channel relay output (2-channel trip, 1-channel alarm, 2-channel trip output (through the starting relay) can separately trip the feeder cabinet circuit breaker with single criterion or double criterion, 1-channel as alarm signal output) module, a reset key, a double-color lamp, a 12V power supply port, a RS485 interface, a cascaded input optical fiber port and a cascaded output optical fiber port.

[0058] The current unit includes: current arc double criterion protection module, feeder trip and alarm module, cascaded input and output module, fixed value and address setting module, and communication alarm information uploading module.

[0059] Using the arc unit, an arc protection system can protect 1500m of medium voltage switch cabinet or 500m of low voltage switch cabinet. In this case, an arc detection unit is installed in each cabinet to protect the switch cabinet. In an open bus system, the interval of the arc detection unit is about 5-6m. The arc protection system provided by the present application can protect several independent switch cabinets at the same time. Therefore, the arc unit and the current unit of the arc protection system can be dispersed into different switch cabinets, and the detected arc or current signals are transmitted to the master control system. The master control system collects the necessary data and outputs the trip signal to the circuit breaker according to the actual situation. The data transmission between the master control system and the arc unit or the current unit is completed by optical fiber and data transmission line. The optical fiber transmits the trigger signal to the master control system. The transmission of working power supply, alarm signal and automatic control data information flow is completed by the data transmission line. The master control system provides four fast ms-level independent trip ports and six conventional relay output ports of the alarm bus.

[0060] The arc detection unit is connected to the optical signal input port behind the arc unit as shown in Figure 2 The input port number is from zero to nine, as shown in Figure 3As shown, the data output cable is connected to the "Data out" port (to the master system or arc unit), and the corresponding trigger signal output fiber is connected to the "trip out" port. The data transmission cable from other arc units is connected to the "Data in" port, and the trigger signal input fiber is connected to the "trip in" port.

[0061] The arc protection system has a self-control program, which controls the operation of the program and displays fault information on the master system. The fault alarm can be sent through the relay outlet 5 to indicate the internal fault of the system. The self-diagnosis control system controls the internal functions of the master system, as well as the communication and functions between the master system, the arc unit and the current unit.

[0062] The setting of the current unit address is the same as that of the arc unit. To ensure that the master system correctly identifies the address of the current unit, the switch state inside the current unit should be correctly set to ensure that each current unit has a different address code. In addition, the addresses of the current unit and the arc unit in the same master system cannot be repeated, and the addresses of the temperature probes, voltage probes, etc. cannot be repeated.

[0063] When an arc occurs in the switch cabinet, the illumination is about 100,000 lux, and the effective working illumination is about 20,000 lux. The sensitivity of the device to light can be adjusted to an appropriate level. Due to different illuminations in different switch cabinets, adjustment is required. In certain situations, the fixed value needs to be increased during installation to avoid unnecessary light alarms. When the arc unit is connected to the protection system, first adjust their light intensity, then adjust the sensitivity of the master system to light according to the trip signal emitted. The light intensity of the arc unit can be adjusted on the potentiometer on its panel. The potentiometer affects all light sensing inputs. Setting the potentiometer to 30,000 lux can ensure that the system works correctly under normal conditions. When the arc unit is connected to the protection system, first adjust their sensitivity to light. This approach ensures that all units have the same light sensitivity. The arc detection unit is directly connected to the master system, and its sensitivity can be adjusted on the panel of the master system.

[0064] The arc unit is installed on the DIN rail at the bottom of the instrument cabinet through the DIN rail at the bottom. The arc unit can also be directly fixed to the bottom of the installation space through the fixing points on its side using 4mm screws. These screws can also be used to fix the DIN rail.

[0065] The optical cable used in the arc protection system is specially developed for different data transmission applications. The optical cable is a single-core cable with a polyethylene jacket that can withstand the most stringent working environment. The optical fiber itself is made of plastic, so no protective equipment or special tools are required during operation. The specific parameters of the optical cable are shown in Table 1.

[0066] Table 1. Specific parameters of the optical cable

[0067]

[0068]

[0069] In some embodiments, as shown in Figure 4 the main control system is connected with 9 arc light detection units, 1 ACU (arc light unit 1) is connected with 8 arc light detection units, 2 ACU (arc light unit 2) is connected with 9 arc light detection units, and 3 ACU (arc light unit 3) is connected with 8 arc light detection units; the main control system is connected with 1 ACU through data line and optical fiber, 2 ACU is connected with 1 ACU through data line and connected with the main control system through optical fiber, and 3 ACU is connected with 2 ACU through data line and optical fiber; 1 CTE (current unit 1) and 2 CTE are connected with the main control system through optical fiber and data line respectively.

[0070] In some embodiments, as shown in Figure 1 the arc light protection system further comprises two groups of auxiliary protection systems, each group of auxiliary protection system comprises a plurality of auxiliary master control units, the auxiliary master control unit is connected with the auxiliary arc light detection unit, the auxiliary arc light detection unit is arranged in the cable chamber, the auxiliary circuit breaker is arranged between the electrical equipment in the cable chamber in the two groups of protection systems and the one section bus and the two section bus, the auxiliary arc light detection unit sends the collected arc light to the auxiliary master control unit, the auxiliary master control unit outputs the trip signal to the auxiliary circuit breaker according to the received arc light, and preferably, the auxiliary master control unit is connected with the main control system; the electrical equipment comprises Figure 1 the standby transformer, the power distribution device, the variable frequency speed regulation pressure pump, the voltage transformer and the like as shown.

[0071] In some embodiments, the main control system further comprises a trip control circuit, which realizes by the following steps:

[0072] collecting the alarm instruction sent by the one section bus and the two section bus, removing the alarm instruction on the two section bus by the mutual exclusion flag, judging whether the arc light alarm and the current alarm occur on the one section bus at the same time, if yes, sending the trip instruction to the first circuit breaker, the second circuit breaker and the relay connected with the second circuit breaker trip loop at the same time;

[0073] removing the alarm instruction on the one section bus by the mutual exclusion flag, judging whether the arc light alarm and the current alarm occur on the two section bus at the same time, if yes, sending the trip instruction to the second circuit breaker, the third circuit breaker, the relay connected with the second circuit breaker loop and the relay connected with the third circuit breaker loop at the same time;

[0074] judging whether the arc light alarm and the current alarm occur on the one section bus and the two section bus respectively, if yes, sending the trip instruction to the second circuit breaker and the relay connected with the second circuit breaker loop at the same time;

[0075] The number of times x that the second circuit breaker and the relay connected to the second circuit breaker loop receive the trip command is counted, and the second circuit breaker and the relay connected to the second circuit breaker loop are set to be closed Y seconds after the fault is eliminated, where Y=y+(x-1)a, and Y represents the recovery time after the fault is eliminated, a represents the time that is extended each time, x represents the number of times, x is a positive integer, and a and y are constants, such as a=2s and y=5min. If there is no arc light on both sections of busbars after the first disconnection of the bus-tie cabinet, a=1, and the connection is restored after 5min. After the second disconnection, a=2, and the recovery time is 5min+2s, and the connection is restored after that time. The same applies to the subsequent disconnections. The elimination of the fault refers to the fact that the arc light alarm and the current alarm of both sections of busbars stop, or that only the arc light alarm or the current alarm of both sections of busbars occurs.

[0076] As shown in Figure 4 the conventional double criterion, the light signals and the corresponding current signals on the first section and the second section are collected. When the arc light+current alarm of the first section occurs, Triac1, Triac4, Triac3, and Relay3 are simultaneously output. When the arc light+current alarm of the second section occurs, Triac2, Realy2, Triac3, and Realy3 are simultaneously output. When the arc light+current alarms of different sections occur, Triac3 and Relay3 are simultaneously output. The specific code is shown as follows:

[0077]

[0078]

[0079]

[0080] The embodiment specifically defines how to trip, for example, when current alarm and arc light alarm occur on a section of bus simultaneously, the bus coupler is disconnected, and the circuit breaker on the section of bus trips, at this time, the section of bus and the second section of bus operate respectively, and the power supply of the second section of bus is not affected; when current alarm occurs on the section of bus and arc light alarm occurs on the second section of bus, at this time, since the arc light alarm and the current alarm do not occur on the two sections of bus simultaneously, it is not clear which section of bus will have arc light, at this time, the bus coupler is disconnected first, so that the two sections of bus can operate respectively and do not affect each other; when the section of bus and the second section of bus do not have secondary alarm within Y minutes (the section of bus has current alarm, and within Y minutes, arc light alarm does not occur, and the second section of bus has arc light alarm, and within Y minutes, current alarm does not occur), at this time, the bus coupler is automatically restored to be connected; the number x of times of receiving the trip command of the second circuit breaker and the relay connected to the second circuit breaker is counted again, that is, the number of times of disconnecting the bus coupler, the more the number of times of disconnecting the bus coupler, the more serious the aging of the electrical equipment is, and attention is needed, in the embodiment, the time of automatically restoring the bus coupler is prolonged as the number of times of disconnecting the bus coupler increases, so that the electrical cabinet can be better protected.

[0081] In some embodiments, the electrical equipment includes a power distribution device and a standby transformer, the power distribution device and the standby transformer are connected with a plurality of loads, the standby transformer is connected with all the loads, and the arc light protection system further includes a standby circuit, and the standby circuit is realized by the following steps:

[0082] The standby transformer is in a tripped state with each load;

[0083] The main control system judges whether the auxiliary circuit breaker between any power distribution device and the section of bus or the second section of bus trips, if the auxiliary circuit breaker trips, the load connected with the corresponding power distribution device is connected with the standby transformer through sending a command;

[0084] The main control system judges whether the auxiliary circuit breaker recovers, if the auxiliary circuit breaker recovers, the standby transformer is again in a tripped state with the load, and the connection between the corresponding load and the power distribution device is restored.

[0085] In the embodiment, the standby transformer is provided, the standby transformer does not start normally and is in a tripped state, when it is judged that arc light occurs in a power distribution device (that is, the auxiliary circuit breaker between any power distribution device and the section of bus or the second section of bus trips), the standby transformer is connected with the load to be powered off, so that a large number of loads are prevented from being suddenly powered off, when the power distribution device in which arc light occurs recovers, the load is tripped with the standby transformer, and the connection between the power distribution device and the load is restored.

[0086] In some embodiments, the arc light protection system includes an arc light current double-criterion circuit, and the arc light current double-criterion circuit is realized by the following steps:

[0087] The master control system or the arc light unit receives the arc light sent by the arc light detection unit, compares the arc light with the arc light threshold value, and sends an arc light alarm to the master control system when the arc light is greater than the arc light threshold value;

[0088] The master control system receives the current signal sent by the power supply unit, converts the current signal into a current, compares the current with a current threshold value, and sends a current alarm to the master control system when the current is greater than the current threshold value.

[0089] In some embodiments, the electric arc light protection system further comprises a temperature measurement probe connected with the master control module, the temperature measurement probe mainly comprises a fiber-optic temperature measurement probe and / or a distributed fiber-optic linear temperature sensing probe, the temperature measurement probe is connected with the master control system through the arc light unit; the arc light unit and the temperature measurement probe transmit optical signals through optical fibers; the arc light unit and the arc light detection unit transmit optical signals through temperature-sensitive optical fibers, and the temperature measurement probe is installed in a busbar room and / or a cable room and / or a circuit breaker room.

[0090] In some embodiments, the cable room and / or the cable room and / or the circuit breaker room are further provided with a temperature and humidity probe, and the electric arc light protection system further comprises a humidity criterion circuit, which realizes the following steps:

[0091] Collecting humidity signals H of each sampling point, comparing all current humidity signals H with a humidity threshold value H 阈 , and comparing the size, when H≥H 阈 , performing step S2, and when H 阈 , then no processing is performed;

[0092] Judging the number of days n that the current position H≥H 阈 is continuous, and comparing the size of n with a day threshold value n 阈 , if n≥n 阈 , then the arc light threshold value and the current threshold value are adjusted downward, and if n 阈 , then no processing is performed.

[0093] When the performance of the insulating material decreases, external factors such as air humidity, consecutive overcast and rainy seasons, and humid environments cause the phenomenon of electric arc climbing along the outer skin between the charged metal part and the insulating material like water ripples; this embodiment detects the humidity signal, when the humidity is greater than the threshold value, the electric arc climbing phenomenon is easy to occur, at this time, if the humidity is too large for many days, it proves that the electric arc climbing phenomenon is easy to occur at this time, if the current increases or the arc light value increases, there is a high probability that the electric arc light will occur, in this case, the arc light threshold value and the current threshold value are adjusted downward, thereby predicting the occurrence of the electric arc light in advance, reducing the disaster occurrence rate, and the adjustment range of the arc light threshold value and the current threshold value adjusted downward can be set according to the actual situation, which is generally fine-tuned.

[0094] In some embodiments, the cable chamber and / or the cable chamber and / or the circuit breaker chamber are provided with an arc light detection unit and a temperature and humidity probe at the same time, and the protection system further comprises an arc light and humidity double criterion circuit, which is realized by the following steps:

[0095] S1: Collect the arc light of each sampling point in the cable chamber, and determine whether the arc light exceeds the arc light threshold value. If yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step S2;

[0096] S2: Collect the humidity signal of each sampling point in the cable chamber, and determine whether the humidity exceeds the humidity threshold value. If yes, adjust the temperature threshold value downward.

[0097] In this embodiment, it is first determined whether the arc light exceeds the threshold value. If it does, the humidity is monitored. If the humidity also exceeds the threshold value, it is proved that the arc light is likely to be caused by excessive humidity, and there is a high possibility of arc light generation. At this time, the temperature threshold value is slightly adjusted downward, and the trip can be performed when the temperature reaches the adjusted threshold value, thereby avoiding the occurrence of serious arc light disaster caused by real arc light.

[0098] In some embodiments, the cable chamber and / or the cable chamber and / or the circuit breaker chamber are provided with a voltage probe and a temperature and humidity probe at the same time, and the protection system further comprises a voltage and humidity double criterion circuit, which is realized by the following steps:

[0099] (1) Collect the voltage signal of each sampling point in the cable chamber, and determine whether the voltage signal exceeds the voltage threshold value. If yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step (2);

[0100] (2) Collect the humidity signal of each sampling point in the cable chamber, and determine whether the humidity exceeds the humidity threshold value. If yes, adjust the temperature threshold value downward, and proceed to step (1).

[0101] In this embodiment, it is first determined whether the voltage exceeds the threshold value. If it does, the trip is performed. If it does not, the humidity signal is collected. If the humidity also exceeds the threshold value, there is a high possibility of arc light generation. At this time, the temperature threshold value is slightly adjusted downward, and the trip can be performed when the temperature reaches the adjusted threshold value, thereby avoiding the occurrence of serious arc light disaster caused by real arc light.

[0102] In some embodiments, the cable chamber and / or the cable chamber and / or the circuit breaker chamber are provided with a voltage probe and a temperature and humidity probe at the same time, and the protection system further comprises a voltage and humidity double criterion circuit, which is realized by the following steps:

[0103] a. Collect the voltage signal of each sampling point in the cable chamber, and determine whether the voltage exceeds the voltage threshold value. If yes, send a trip message to the corresponding auxiliary circuit breaker; if no, proceed to step b;

[0104] b. Then the temperature signal of each sampling point in the cable room is collected to determine whether the temperature exceeds the temperature threshold value, and if so, the arc light threshold value is adjusted downward.

[0105] In this embodiment, the voltage signal is collected to determine whether it exceeds the threshold value, and if so, the trip is performed, and if not, the temperature signal is collected, and when the temperature exceeds the threshold value, the arc light threshold value is finely adjusted downward, and the trip can be performed when the arc light reaches the threshold value after the fine adjustment, thereby avoiding the serious arc light disaster caused by the real arc light.

[0106] The application also provides an application of the arc light protection system in the pumped storage power station and the hydropower station.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the application and are not limiting. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the application, and they should be covered in the scope of the claims of the application.

Claims

1. An arc flash protection system for use in power plants, characterized in that, The arc flash protection system includes a main control system and a power module, a first current unit, a second current unit, a first arc flash unit, a second arc flash unit, and a third arc flash unit connected to the main control system. The power station bus includes a first section bus, a second section bus, and a segmented bus. The power circuit on the first section bus is equipped with a first circuit breaker, the first section bus is equipped with a second circuit breaker between the first section bus and the segmented bus, and the power circuit on the second section bus is equipped with a third circuit breaker. The main control system protects at least one switchgear of the power station. The first current unit and the second current unit are directly connected to the main control system at one end via optical fiber and data line, and their other ends are respectively connected to a first current transformer and a second current transformer. The first current transformer is used to collect the incoming current of a section of bus power supply, and the second current transformer is used to collect the incoming current of two sections of bus power supply. The first arc light unit is connected to the main control system via data line and optical fiber. The second arc light unit is connected to the main control system via optical fiber and to the first arc light unit via data line. The third arc light unit is connected to the second arc light unit via data line and optical fiber. Both the first and third arc light units are connected to several arc light detection units via optical fiber. The second arc light unit is connected to several arc light detection units via optical fiber. The main control system is also connected to several arc light detection units via optical fiber. All arc light detection units are installed in the bus compartment and the circuit breaker compartment. The main control system outputs a trip signal to the first circuit breaker, the second circuit breaker, or the third circuit breaker based on the received arc and current signals. The main control system also includes a trip control circuit, which is implemented through the following steps: Collect alarm commands sent from the first busbar and the second busbar, remove the alarm commands from the second busbar using the mutual exclusion flag, determine whether an arc alarm and a current alarm occur simultaneously on the first busbar, and if so, send trip commands to the first circuit breaker, the second circuit breaker, and the relay connected to the trip circuit of the second circuit breaker. The mutual exclusion flag removes the alarm command on one busbar, determines whether arcing alarm and current alarm occur simultaneously on the two busbars, and if so, sends trip commands to the second circuit breaker, the third circuit breaker, the relay connected to the second circuit breaker circuit, and the relay connected to the third circuit breaker circuit. Determine whether arcing alarm and current alarm have occurred on the first and second busbars respectively. If so, send a trip command to the second circuit breaker and the relay connected to the second circuit breaker circuit at the same time. The number of times x is received by the second circuit breaker and the relay connected to the second circuit breaker circuit. After the fault is cleared, the second circuit breaker and the relay connected to the second circuit breaker circuit are closed after Y seconds. Y = y + (x-1)a, where Y represents the recovery time after the fault is cleared, a represents the time extension for each additional trip, x represents the number of trips, x is a positive integer, and a and y are constants. The fault clearing refers to the cessation of arc flash alarm and current alarm on both bus section 1 and bus section 2, or the occurrence of arc flash alarm or current alarm on bus section 1 and bus section 2.

2. The arc flash protection system for power plants according to claim 1, characterized in that, The arc flash protection system also includes two sets of auxiliary protection systems. Each set of auxiliary protection systems includes several auxiliary main control units. The auxiliary main control units are connected to auxiliary arc flash detection units, which are installed in the cable compartment. Auxiliary circuit breakers are installed between the first busbar and the second busbar and the electrical equipment in the cable compartment of the two sets of protection systems, respectively. The auxiliary arc flash detection units send the collected arc flash to the auxiliary main control units. The auxiliary main control units output trip signals to the auxiliary circuit breakers based on the received arc flash.

3. The arc flash protection system for power plants as described in claim 2, characterized in that, The secondary main control unit is connected to the main control system.

4. The arc flash protection system for power plants according to claim 2, characterized in that, The electrical equipment includes a power distribution device and a backup transformer. Both the power distribution device and the backup transformer are connected to several loads. The backup transformer is connected to all of the loads. The arc flash protection system also includes a backup circuit, which is implemented by the following steps: the backup transformer is in a tripped state with each load. The main control system determines whether the auxiliary circuit breaker between any power distribution device and one or two busbars has tripped. If it has tripped, it sends a command to connect the load connected to the corresponding power distribution device to the standby transformer. The main control system determines whether the secondary circuit breaker has recovered. If it has, the standby transformer is disconnected from the load again, and the connection between the corresponding load and the power distribution device is restored.

5. The arc flash protection system for power plants according to claim 1, characterized in that, The arc flash protection system includes a dual-criteria circuit for arc flash current; the dual-criteria circuit for arc flash current is implemented by the following steps: The main control system or the arc light unit receives the arc light sent by the arc light detection unit, compares the arc light with the arc light threshold, and sends an arc light alarm to the main control system when the arc light is greater than the arc light threshold. The main control system receives the current signal sent by the power supply unit, converts the current signal into a current and compares it with a current threshold. When the current is greater than the current threshold, a current alarm is sent to the main control system.

6. The arc flash protection system for power plants according to claim 2, characterized in that, The arc flash protection system also includes a temperature probe connected to the main control module. The temperature probe mainly includes an optical fiber temperature probe and / or a distributed optical fiber linear temperature detector. The temperature probe is connected to the main control system through the arc flash unit. Optical signals are transmitted between the arc flash unit and the temperature probe through optical fiber. Optical signals are transmitted between the arc flash unit and the arc flash detection unit through a temperature-sensitive optical fiber. The temperature probe is installed in the busbar room and / or the cable room and / or the circuit breaker room.

7. The arc flash protection system for power plants as described in claim 5, characterized in that, The cable room and / or the circuit breaker room are also equipped with temperature and humidity probes. The arc flash protection system further includes a humidity criterion circuit, which is implemented through the following steps: Collect humidity signals H from each sampling point, and compare all current humidity signals H with the humidity threshold H. 阈 Compare the sizes when H ≥ H 阈 When H < H, proceed to step S2. 阈 If so, no action is taken; Determine if the current position H ≥ H 阈 The duration n is calculated, and n is compared with the number of days threshold n. 阈 The size, if n≥n 阈 If n < n 阈 If so, no action will be taken.

8. The arc flash protection system for power plants according to claim 1, characterized in that, The cable room and / or the cable room and / or the circuit breaker room are simultaneously equipped with an arc flash detection unit and a temperature and humidity probe. The protection system also includes an arc flash and humidity dual criterion circuit, which is implemented through the following steps: S1: Collect arc light at each sampling point in the cable room, and determine whether the arc light exceeds the arc light threshold. If it does, send a trip message to the corresponding secondary circuit breaker; otherwise, proceed to step S2. S2: Collect humidity signals from each sampling point in the cable room, determine whether the humidity exceeds the humidity threshold, and if so, adjust the temperature threshold downwards.

9. The arc flash protection system for power plants according to claim 6, characterized in that, The cable compartment and / or the cable compartment and / or the circuit breaker compartment are simultaneously equipped with voltage probes and temperature and humidity probes. The protection system also includes a voltage and humidity dual-criteria circuit, which is implemented through the following steps: (1) Collect the voltage signal of each sampling point in the cable room, and determine whether the voltage signal exceeds the voltage threshold. If yes, send a trip message to the corresponding secondary circuit breaker. If no, proceed to step (2). (2) Collect humidity signals from each sampling point in the cable room, determine whether the humidity exceeds the humidity threshold, and if so, adjust the temperature threshold downward and proceed to step (1).

10. The arc flash protection system for power plants according to claim 9, characterized in that, The cable compartment and / or the circuit breaker compartment are equipped with both voltage probes and temperature probes. The arc flash protection system further includes a voltage and temperature dual-criteria circuit, which is implemented through the following steps: a. Collect voltage signals from each sampling point in the cable room and determine whether the voltage exceeds the voltage threshold. If it does, send a trip message to the corresponding secondary circuit breaker. If not, proceed to step b. b. Then collect the temperature signals of each sampling point in the cable room, determine whether the temperature exceeds the temperature threshold, and if so, adjust the arc threshold downward.

11. The application of the arc flash protection system for power plants according to any one of claims 1-10 in pumped storage power plants and hydropower plants.

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