阅读说明：本技术 一种降低核电厂稳压器电加热器开关故障率的方法 (Method for reducing switch failure rate of electric heater of voltage stabilizer in nuclear power plant ) 是由 李洪伟 徐霞军 郭莉侠 王雄辉 *** 张雅文 石岩 吴东方 王镜琪 翁铖忠 徐 于 2020-06-04 设计创作，主要内容包括：本发明涉及核电站电气维修技术领域,尤其涉及一种降低核电厂稳压器电加热器开关故障率的方法。所述方法为：开关平均为X组,每组N个开关,同一组的各个开关不相邻；在1个换料循环周期内,选定一组电加热器开关标记为长期组电加热器开关,其他电加热器开关标记为短期组电加热器开关；以后的换料循环周期内,选定一组未被标记过作为长期组电加热器的开关标记为长期组电加热器开关,其他电加热器开关标记为短期组电加热器开关。直至每个电加热器开关被标记过一次作为长期组电加热器开关,N-1次作为短期组电加热器开关,再按前述的标记顺序重新标记,往复循环。所述方法,降低了开关的运行温度及故障率,保障稳压器电加热器的安全稳定运行。(The invention relates to the technical field of electrical maintenance of nuclear power plants, in particular to a method for reducing the failure rate of an electric heater of a voltage stabilizer of a nuclear power plant. The method comprises the following steps: the switches are averagely X groups, each group of N switches, and the switches of the same group are not adjacent; in 1 material changing cycle period, selecting one group of electric heater switches as long-term group electric heater switches, and other electric heater switches as short-term group electric heater switches; in subsequent refueling cycle periods, a group of switches which are not marked as long-term group electric heaters are selected and marked as long-term group electric heater switches, and other electric heater switches are marked as short-term group electric heater switches. Until each electric heater switch is marked once as a long-term group electric heater switch, and N-1 times as a short-term group electric heater switch, and then the electric heater switches are marked again according to the marking sequence, and the cycle is repeated. The method reduces the operating temperature and the failure rate of the switch, and ensures the safe and stable operation of the electric heater of the voltage stabilizer.)

1. A method of reducing the failure rate of a nuclear power plant voltage regulator electric heater switch, comprising the steps of:

step S1: all the voltage stabilizer electric heater switches are averagely divided into X groups, each group of N switches, and the switches of the same group are not adjacent; n is more than or equal to 1, N is the number of switches corresponding to the long-term group of electric heaters, and X is a positive integer;

step S2: in 1 material changing cycle period, selecting one group of voltage stabilizer electric heater switches as long-term group electric heater switches, and selecting other voltage stabilizer electric heater switches as short-term group electric heater switches;

step S3: in the subsequent material changing cycle period, a group of switches which are not marked as long-term group electric heaters are selected to be marked as long-term group electric heater switches, and other voltage stabilizer electric heater switches are marked as short-term group electric heater switches; until each voltage stabilizer electric heater switch is marked once as a long-term group electric heater switch, and N-1 times as a short-term group electric heater switch, marking again according to the marking sequence, and performing reciprocating circulation; the voltage stabilizer electric heater switches correspond to the voltage stabilizer electric heaters one by one.

2. The method for reducing the failure rate of the electric heater of the nuclear power plant voltage stabilizer according to claim 1, wherein N is 4-8.

3. The method of reducing the failure rate of a nuclear power plant regulator electric heater switch of claim 1, wherein the total number of regulator electric heater switches is 28.

4. The method of reducing the failure rate of nuclear power plant regulator electric heater switches of claim 1, wherein all regulator electric heater switches are arranged in columns, a set of cooling devices is arranged at the top of each column of switch sets, and cooling holes are arranged on each switch and the partition floor.

5. The method of reducing the failure rate of a nuclear power plant regulator electric heater switch of claim 4, wherein the cooling device operates as a switch operates.

6. The method of reducing the failure rate of nuclear power plant regulator electric heater switches of claim 1, wherein the conductive cross section of a loop of each regulator electric heater switch is increased to reduce the direct resistance of the loop.

7. The method of reducing the failure rate of a nuclear power plant regulator electric heater switch of claim 6, wherein the input and output conductor portions of the regulator electric heater switch are double-plug conductors.

8. The method for reducing the failure rate of a nuclear power plant regulator electric heater switch of claim 1, wherein in steps S2-S3, the signature of the long-term group electric heater switch is modified by modifying instrumentation control logic.

Technical Field

The invention relates to the technical field of electrical maintenance of nuclear power plants, in particular to a method for reducing the failure rate of an electric heater of a voltage stabilizer of a nuclear power plant.

Background

The pressurizer is a key device for maintaining pressure in a primary circuit of a nuclear power plant reactor, and water (water and steam) in a two-phase state is stored in the pressurizer. During normal operation of the nuclear power plant, the water in liquid and gas phase is in dynamic equilibrium, i.e. the pressure in the pressurizer is equal to the saturated vapor pressure of water at an average coolant temperature of 310 ℃. The pressure in the pressure stabilizer is stabilized by timely and dynamically adjusting the spray valve and the electric heater of the pressure stabilizer.

A loop of each unit of a unit of No. 1 and No. 2 of a certain nuclear power station is provided with 1 voltage stabilizer, the voltage stabilizer is provided with 28 electric heaters and divided into two layers, and 14 electric heaters are uniformly distributed at the bottom of each layer. The 28 electric heaters adopt a fixed logic and fixed operation mode. The 4 electric heater units are in a live-line operation state or a frequent start-stop state for a long time during the operation period and are collectively called long-term group electric heaters, and the 24 electric heaters only operate in the start-stop stage of the units and are collectively called short-term group electric heaters. Each electric heater is provided with a set of independent electric power supply loops, each electric power supply loop is a switch, and the switches of the 28 electric heaters are designed on two sections of alternating current buses. Each section of bus is divided into 1 column of power supply incoming line switch cabinets and 3 columns of load switch cabinets. 3-5 switch intervals at the top and 1 switch interval at the bottom of each row in the load switch cabinet are standby, and the switch interval at the middle part is a switch corresponding to the electric heater. The switch stacks are adjacent one above the other. Over a decade of operation, the switches of voltage regulator electric heaters have many burnout failures. The infrared imager is used for actually measuring the internal temperature of each switch, and the highest temperature of the switches corresponding to different electric heaters is different and is between 80 and 120 ℃, and is far higher than the reliable working temperature of the switches. In particular: the switches of the long-term group electric heaters are adjacent up and down, and the corresponding switches generate heat most seriously due to the long-term charged state of the long-term group electric heaters during the normal operation of the unit.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for reducing the failure rate of the electric heater of the voltage stabilizer in the nuclear power plant is provided, the operation temperature of the electric heating switch is reduced, the failure rate of the electric heating switch is reduced, the operation reliability of the switch and an alternating current bus is improved, and the safe and stable operation of the electric heater of the voltage stabilizer is guaranteed.

The invention provides a method for reducing the failure rate of an electric heater switch of a voltage stabilizer in a nuclear power plant, which comprises the following steps:

step S1: all the voltage stabilizer electric heater switches are averagely divided into X groups, each group of N switches, and the switches of the same group are not adjacent; n is more than or equal to 1, N is the number of switches corresponding to the long-term group of electric heaters, and X is a positive integer;

step S2: in 1 material changing cycle period, selecting one group of voltage stabilizer electric heater switches as long-term group electric heater switches, and selecting other voltage stabilizer electric heater switches as short-term group electric heater switches;

step S3: in the subsequent material changing cycle period, a group of switches which are not marked as long-term group electric heaters are selected to be marked as long-term group electric heater switches, and other voltage stabilizer electric heater switches are marked as short-term group electric heater switches; until each voltage stabilizer electric heater switch is marked once as a long-term group electric heater switch, and N-1 times as a short-term group electric heater switch, marking again according to the marking sequence, and performing reciprocating circulation; the voltage stabilizer electric heater switches correspond to the voltage stabilizer electric heaters one by one.

Preferably, N is 4-8.

Preferably, the regulator electrical heater switches are 28 in number overall.

Preferably, all the voltage stabilizer electric heater switches are arranged in rows, a set of cooling device is arranged at the top of each row of switch group, and heat dissipation holes are formed in each switch and the partition floor.

Preferably, the cooling means operates in response to operation of the switch.

Preferably, the conductive cross section of a loop of each regulator electric heater switch is increased to reduce the direct resistance of the loop.

Preferably, the input and output conductor portions of the regulator electric heater switch are double-plug conductors.

Preferably, in said steps S2-S3, the signature of the long-term group electric heater switch is modified by modifying the instrumentation logic.

Compared with the prior art, the method for reducing the failure rate of the electric heater of the voltage stabilizer in the nuclear power plant has the following beneficial effects:

(1) each voltage stabilizer electric heater switch is marked as a long-term group electric heater switch in turn, so that the occurrence of elastic aging is effectively avoided, and the failure rate of the switches is reduced.

(2) The switches of the same group of electric heaters are not adjacent, so that the adjacent formation of a heat island effect when any group of switches are used as the switches of the electric heaters for a long time can be avoided.

Furthermore, the conductive section of each electric heater switch loop is enlarged to reduce the direct resistance of the loop and reduce the heat productivity inside the switch; and a cooling device is added to accelerate the air flow in the switch, so that the temperature in the switch is reduced.

Through the improvement, the operation temperature of each switch in the electric heater switch cabinet can be reduced to below 70 ℃, the temperature difference between the switches on the upper layer and the switches on the lower layer of the load switch group can be reduced to below 10 ℃, the burning fault caused by the heating of the switches is effectively avoided, the risk of the power loss of the alternating current bus is reduced, and the operation reliability of the switches and the alternating current bus is improved.

Drawings

Fig. 1 is a schematic structural view of a switchgear in embodiment 1;

wherein 1 is an alternating current bus section; 2 is a spare switch interval; 3-1 to 3-4 are serial numbers of all rows in the switch cabinet; 4 is a power supply incoming line switch; the first to the seventh are grouped group numbers; 901A, 901B, 901C, 902A, 902B, 902C, 903A, 903B, 903C, 903D, 903E, 903F, 903G, 903H, 904A, 904B, 904C, 904D, 904E, 904F, 904G, 904H, 904J, 904K, 904L, 904M, 904N, and 904P are the numbers of the respective regulator electric heater switches, respectively.

Detailed Description

For a further understanding of the invention, embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are included merely to further illustrate features and advantages of the invention, and are not intended to limit the invention.

The embodiment of the invention discloses a method for reducing the failure rate of an electric heater of a voltage stabilizer in a nuclear power plant, which comprises the following steps:

step S1: all the voltage stabilizer electric heater switches are averagely divided into X groups, each group of N switches, and the switches of the same group are not adjacent; n is more than or equal to 1, N is the number of switches corresponding to the long-term group of electric heaters, and X is a positive integer;

step S2: in 1 material changing cycle period, selecting one group of voltage stabilizer electric heater switches as long-term group electric heater switches, and selecting other voltage stabilizer electric heater switches as short-term group electric heater switches;

step S3: in the subsequent material changing cycle period, a group of switches which are not marked as long-term group electric heaters are selected to be marked as long-term group electric heater switches, and other voltage stabilizer electric heater switches are marked as short-term group electric heater switches; until each voltage stabilizer electric heater switch is marked once as a long-term group electric heater switch, and N-1 times as a short-term group electric heater switch, marking again according to the marking sequence, and performing reciprocating circulation; the voltage stabilizer electric heater switches correspond to the voltage stabilizer electric heaters one by one. The voltage stabilizer electric heater is put into or out of operation along with the on-off state of the corresponding switch. Preferably, the total number of regulator electrical heater switches is 28.

Preferably, in the step S1, N is 4 to 8.

More preferably, N is equal to the number of long-term group electric heaters, and N is 4.

Preferably, X is 4-10.

More preferably, the total number of the potentiostat electric heaters is 28, said X ÷ 28 ÷ N ÷ 28 ÷ 4 ÷ 7.

Preferably, in said steps S2-S3, the signature of the long-term group electric heater switch is modified by modifying the instrumentation logic.

Preferably, all the voltage stabilizer electric heater switches are arranged in rows, a set of cooling device is arranged at the top of each row of switch group, and heat dissipation holes are formed in each switch and the partition floor.

More preferably, the cooling means operates with the switch operating.

Preferably, the conductive section of each voltage stabilizer electric heater switch loop is increased to reduce the direct resistance of the loop, and more preferably, the input and output conductor parts of the voltage stabilizer electric heater switch are double-plug conductors.

The invention adopts an operation method of regularly alternating logic sequences, and the long-term group electric heater switch and the short-term group electric heater switch are marked by modifying the instrument control logic circulation, so that the switches of the voltage stabilizer electric heaters are circularly and alternately used as the long-term group electric heater switches, and the operation time of each switch tends to be balanced in a certain period time. And the switches of the electric heaters of the same group of voltage stabilizers are not adjacent through grouping, so that the phenomenon that the switches of the electric heaters of the group are adjacent to form a heat island effect during the normal operation of the unit for a long time is avoided. And the cooling device is added to increase the conductive section of each voltage stabilizer electric heater switch loop so as to reduce the direct resistance of the loop. In the voltage stabilizer electric heater switch cabinet, the operating temperature of each switch can be reduced to below 70 ℃, the temperature difference between the switches on the upper layer and the switches on the lower layer of the load switch group can be reduced to below 10 ℃, the burning fault caused by heating of the switches is effectively avoided, the risk of power loss of the alternating current bus is reduced, and the reliability of the operation of the switches and the alternating current bus is improved.

For further understanding of the present invention, the method for reducing the failure rate of the electric heater of the voltage stabilizer in the nuclear power plant provided by the present invention is described in detail with reference to the following embodiments, and the scope of the present invention is not limited by the following embodiments.