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(1) Two-vote three-system

1. The concept of two votes and three systems

Two tickets: work ticket, operation ticket;

Three systems: shift system, patrol inspection system, and equipment periodic test switching system.

The system generally used in thermal power plants, the thermal and mechanical parts of the "Safety Work Regulations for the Electric Power Industry" also have provisions on this content.

2. Precautions for the application of the two-vote three-system

"Two votes and three systems" is one of the most basic systems in the safety production guarantee system of the electric power industry.

According to the experience, the analysis of any man-made liability accident can find the reason in its implementation of the "two votes and three systems".

In order to implement the safety policy, improve the ability to prevent accidents, put an end to man-made accidents, and prevent malignant misuse accidents, the "two votes and three systems" must be

It must be strictly implemented, and the following points should be noted:

(1) Increase the execution and management of operation tickets.

(2) Strictly manage work tickets and eliminate operations without tickets.

(3) Conscientiously implement the shift system.

(4) Improve the quality of operation personnel's supervision and inspection, and strengthen the ability of operation personnel to detect problems in a timely manner.

(5) The regular test and rotation system is a work that should not be ignored in the "two votes and three systems".

An important means of keeping in good condition.

(2) Two measures

The two measures refer to the safety technical measures plan and the anti-accident measures plan.

The main contents of the anti-accident measures plan are:

1. Prevention of personal injury or death

It mainly includes strengthening the analysis of hazardous points in the workplace and taking various safety measures, strengthening the training of operators, strengthening the management of outsourced engineering personnel, and strengthening the inspection of safety tools and equipment.

2. Prevent system stability damage accidents

It mainly includes the strengthening of power grid planning and construction, safe operation of power grids and technical measures, calculation and analysis of system security and stability, and prevention of system voltage collapse.

3. Prevent machine-network coordination accidents

It mainly includes strengthening the management of equipment closely related to the generator set and the power grid, strengthening the management of the primary frequency modulation operation of the generator set, strengthening the management of the generator set parameters, and measures to prevent the power grid and power generation equipment accidents under abnormal and special operation modes of the generator.

4. Prevent electrical misoperation accidents

It mainly includes strengthening anti-misoperation management, improving anti-misoperation technical measures, and strengthening misoperation prevention training for operation and maintenance personnel.

5. Prevent the complete shutdown of the hub substation

It mainly includes improving the primary equipment construction of the hub substation, preventing the complete shutdown of the hub substation caused by the failure of the DC system, preventing the complete shutdown of the hub substation caused by the malfunction of the relay protection, preventing the bus failure causing the complete shutdown of the hub substation, and preventing the hub substation due to improper operation. Wait for the content.

6. Prevent transmission line accidents

It mainly includes the key requirements and issues that should be paid attention to in the design, infrastructure and operation stages.

7. Preventing pollution flashover accidents of power transmission and transformation equipment

It mainly includes the key requirements and issues that should be paid attention to in the design, infrastructure and operation stages.

8. Prevent accidents of DC transmission and converter equipment

Mainly include preventing converter valve damage accident, preventing converter transformer (smoothing reactor) accident, preventing DC switching accident, preventing DC wall bushing accident, preventing insulator discharge accident, preventing DC control and protection equipment accident, etc.

9. Prevent large transformer damage accidents

It mainly includes strengthening the whole process management of transformers, relevant testing and transportation requirements, preventing transformer insulation accidents, preventing tap changer accidents, taking measures to ensure reliable operation of the cooling system, strengthening relevant protection management of transformers, preventing transformer short-circuit accident damage, and preventing bushing accidents. , Prevention of transformer fire accidents, etc.

10. Prevent transformer damage accidents

It mainly includes accident prevention measures for various oil-immersed transformers and 110kV ~ 500kV SF6 insulated current transformers.

11. Prevent switchgear accidents

It mainly includes technical measures for selecting high-voltage switchgear, accident measures for newly installed and overhauled switchgear, measures to prevent switchgear refusal to operate and malfunction, measures to prevent circuit breaker arc extinguishing chamber accidents, and measures to prevent overheating of the current-carrying circuit of switchgear. measures, etc.

12. Prevent grounding grid and overvoltage accident

Mainly include preventing grounding grid accidents, preventing lightning overvoltage accidents, preventing transformer neutral point overvoltage accidents, preventing resonance overvoltage accidents, preventing arc grounding overvoltage accidents, preventing parallel capacitor compensation device operation overvoltage accidents, preventing lightning arrester accidents, etc. .

13. Prevent DC system accidents

It mainly includes strengthening the operation management and maintenance of the battery pack, ensuring the safe and stable operation of the DC system equipment, strengthening the technical and management measures to prevent the misoperation of the DC system, the configuration principles of the DC system, and strengthening the fire prevention work of the DC system.

14. Prevent relay protection accidents

It mainly proposes preventive measures from the aspects of planning, relay protection configuration, relay protection design, infrastructure commissioning and acceptance, operation management, fixed value management, secondary circuit, and relay protection technical supervision.

15. To prevent accidents of power grid dispatch automation system and power communication network, relevant requirements are mainly put forward in terms of network setting requirements, power metering master station system, power supply of dispatch automation master station system, and communication transmission channel settings.

16. Preventing dam collapse and flooding of factory buildings should take preventive measures mainly from the aspects of improving the flood control organization, flood control inspection, flood control and emergency equipment and material reserves, and strengthening the operation and management of hydropower plants and reservoirs.

17. Prevention of fire accidents

Mainly put forward requirements from the aspects of strengthening fire prevention organization and management of fire protection facilities, cable fire prevention, fire prevention measures on maintenance site, battery room fire prevention measures, etc.

18. Preventing traffic accidents

It mainly includes establishing and improving traffic safety management institutions, strengthening the maintenance and management of various vehicles, and strengthening the management and education of drivers.

(3) NOSA system

NOSA is the abbreviation of National Occupational Safety Association. The system is based on risk management, emphasizing the concept of humanized management and continuous improvement, and the goal is to achieve comprehensive risk management of safety, health and environmental protection. It comprehensively calculates each element from "four levels, three aspects, and five levels" to measure whether the risk of this element has been effectively controlled.

The "four levels" refer to: risk awareness, documentation system, compliance, and implementation effect.

"Three aspects" refer to: safety, health and environment.

"Five grades" means: 0, 25, 50, 75, 100 five score levels.

NOSA includes: housing and housekeeping (factory) processing, mechanical, electrical and personal installations, fire and other emergency risk management, safety, health and environmental accident records and investigations, institutional management 5 units, 72 elements, more than 300 basic standards, more than 1,200 Articles of Implementation.

The main features of the system:

(1) Designed for conventional industrial enterprises, it is a highly comprehensive safety, health and environmental management standard;

(2) Risk control covering all types of hazards in conventional industrial enterprises;

(3) Based on risk assessment, guide enterprises to design unique management systems according to specific risks;

(4) Compliance is only the minimum requirement, advocating to be guided by higher than regulatory requirements and international best practices;

(5) Emphasis on the process, but also on the result.

(4) Basic knowledge of power system

1. Explanation of common terms

(1) Three-phase alternating current: A power system composed of three alternating current circuits with the same frequency, equal potential amplitude, and a phase difference of 120° from each other is called three-phase alternating current.

(2) Primary equipment: The equipment directly related to the production of electric energy and power transmission and distribution is called primary equipment. Including various high-voltage circuit breakers, isolating switches, busbars, power cables, voltage transformers, current transformers, reactors, arresters, arc suppression coils, shunt capacitors and high-voltage fuses.

(3) Secondary equipment: auxiliary equipment for monitoring, measurement, manipulation control and protection of primary equipment. Such as various relays, signaling devices, measuring instruments, wave recording devices, telemetry, remote signaling devices and various control cables, small busbars, etc.

(4) High-voltage circuit breaker: also known as high-voltage switch, it can not only cut off or close the no-load current and load current in the high-voltage circuit, but also cut off the overload current and short-circuit through the action of the relay protection device when the system fails. current. It has quite perfect arc extinguishing structure and enough current breaking capacity.

(5) Load switch: The structure of the load switch is similar to that of the isolating switch, but a simple arc extinguishing device is added. It also has an obvious disconnection point, has a certain breaking capacity, and can be operated with load, but cannot directly disconnect the short-circuit current. If necessary, it must be realized by a high-voltage fuse connected in series with it.

(6) Air circuit breaker (automatic switch): It is a low-voltage switch with manual (or electric) closing, maintaining the closing position with a lock, and the tripping mechanism acts on the trip and has an arc extinguishing device. It is currently widely used in In AC and DC devices below 500V, when overload, short circuit, voltage drop or disappearance occurs in the circuit, the circuit can be automatically cut off.

(7) Cable: A wire composed of three parts: a core wire (conductive part), an external insulating layer and a protective layer is called a cable.

(8) Busbar: The electrical busbar is a channel device that collects and distributes electrical energy. It determines the number of power distribution equipment and indicates how to connect generators, transformers and lines, and how to connect with the system to complete power transmission and distribution. Task.

(9) Current transformer: Also known as instrumental current transformer, it is an instrument that converts large current into small current.

(10) Transformer: A static electrical device that is used to convert an AC voltage of a certain value into another AC voltage of the same frequency or several values ​​of different values.

(11) High-voltage test pen: a tool used to check whether high-voltage network transformation and distribution equipment, overhead lines, and cables are live.

(12) Grounding wire: It is an important tool to ensure the staff when the voltage unexpectedly appears on the equipment and lines that have been powered off. According to ministerial regulations, the grounding wire must be made of bare copper flexible wire of 25mm 2 or more.

(13) Signs: used to warn people not to approach the equipment and live parts, to indicate the work place prepared for the staff, to remind to take safety measures, and to prohibit the closing and electrification of a small amount of equipment or a certain line. It can be divided into warning class, allow class, prompt class and prohibition class.

(14) Barrier: In order to prevent the staff from accidentally touching the part of the live equipment, the screen guard of the equipment is divided into temporary barrier and permanent barrier.

(15) Insulation rod: also known as gram rod, insulation rod, operating rod, etc. The insulating rod is composed of three parts: the working head, the insulating rod and the handle. It is used for closing or opening high-voltage isolating switches, assembling and disassembling portable grounding wires, and performing measurements and tests.

(16) Step voltage: If there is a potential difference between two points with a horizontal distance of 0.8m on the ground, when the two feet of the human body touch the two points, the human body will bear a voltage, which is called the step voltage. The largest step voltage occurs between the ground level distance of 0.8m from the ground body and the ground body.

(17) Phase sequence: It is the sequence of the phases, which is the sequence in which the instantaneous value of the alternating current changes from a negative value to a positive value and passes through the zero value.

(18) Power grid: The power grid is a part of the power system. It is a unified network composed of various substations (stations) and transmission and distribution lines of various voltage levels.

(19) Power system: The power system is a part of the power system, which consists of generators and power distribution devices of power plants, boost and step-down substations, transmission and distribution lines, and electrical equipment of users.

(20) Power system: power plants, substations and user's electrical equipment, whose phases are connected by the power grid and the heat grid (or hydraulic) system are called the power system.

2. Basic common sense

(1) Safe voltage, resistance, current

It is stipulated in the safety work regulations: the equipment-to-ground voltage is higher than 250V as high voltage; below 250V is low voltage; the safe voltage is below 36V; the safe current is below 10mA. In the series circuit of resistance, capacitance and inductance, only the resistance consumes electric energy, while the inductance and capacitance only carry out energy transformation. The maximum allowable temperature of the outer skin of the current transformer is 75℃.

If two resistors with the same rated voltage are connected in series in the circuit, the resistor with the larger resistance will generate more heat. The primary current of the current transformer is determined by the load current of the primary circuit, and it does not change with the impedance of the secondary circuit, which is the main difference from the working principle of the transformer.

(2) Substation

The commonly used DC power supplies in substations (stations) include batteries, silicon rectifiers, and capacitor energy storage. The maximum allowable temperature of equipment connectors and wire clips in substations (stations) is 85°C. Substation (station) control room signals are generally divided into voltage signals; current signals; resistance signals. The emergency lighting of the substation (station) must be an independent power supply, and cannot be mixed with the common lighting circuit. The switching operation of the substation (station) must be performed by two people, among which the person who is familiar with the equipment is the guardian.

(3) Transformer

In the graphic symbol of the transformer, Y represents the three-phase coil star connection. The oil of the power transformer plays the role of insulation and arc extinguishing.

The function of the transformer oil pillow is to adjust the oil quantity and prolong the service life of the oil. The volume of the oil pillow is generally one tenth of the total volume of the transformer.

When there is an internal fault in the transformer, the upper contact of the gas relay is connected to the signal circuit, and the lower ground is connected to the switch trip circuit.

The cooling methods of transformers include oil-immersed self-cooling, oil-immersed air-cooled, strong oil air-cooled and strong oil-water cooling.

(4) Insulating rods, insulating gloves and insulating boots

Insulation rods should be kept out of contact with the ground and walls to prevent deformation due to moisture. The testing period for insulating gloves is every six months. The test period for insulating boots is every six months. When operating with insulating gloves, the cuffs of the coat should be put into the insulating gloves. When it is necessary to inspect outdoor high-voltage equipment during thunderstorms, insulating boots should be worn, and lightning arresters, lightning rods and grounding devices should not be approached.

(5) Multimeter

The switch of the multimeter is a switch that realizes various measurement types and ranges.

(6) Safety on duty

A guardian must be present when moving away from or over a barrier during the shift.

The inspection of high-voltage equipment by the on-duty personnel is generally carried out by two people. The commonly used tools of the operator on duty are wire cutters, screwdrivers, electrician's knives, flappers, needle-nose pliers, electric soldering irons and low-voltage test pens.

(7) Safety distance

The guards on duty need to remove the barrier for work, and the required safety distance is 0.7m at 10kV, 1.0m at 35kV, 1.5m at 110kV, and 3.0m at 220kV. When the high-voltage equipment has a ground fault, the safe distance of the grounding point of the human body: indoors should be greater than 4m, and outdoor should be greater than 8m.

(8) Security terms

The term for the pulling and closing operation of a high-voltage circuit breaker or isolating switch shall bepull open, close. The term of switching operation of relay protection device and automatic device shall be input and release. The operating terms for the installation and removal of the ground wire in the electrical inspection are installation and removal.

(9) Electrical appliances

Requirements for the relay: 1. The error of the action value should be small; 2. The contact should be reliable; 3. The return time should be short; 4. The power consumption should be small.

The relay protection device is composed of various relays. After the signal relay is activated, it should drop the card while the contact is closed to connect other signals. The line relay protection device can quickly cut off the faulty part and send a signal when the line fails.