Relay protection, electroautomatics, telemechanics and secondary circuits

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Encyclopedia of radio electronics and electrical engineering / Electrician

Section 2. Electrical equipment and electrical installations for general purposes

Chapter 2.6. Relay protection, electroautomatics, telemechanics and secondary circuits

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Encyclopedia of radio electronics and electrical engineering / Rules for the technical operation of consumer electrical installations (PTE)

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2.6.1. The power electrical equipment of substations, electrical networks and electrical installations of the Consumer must be protected from short circuits and violations of normal modes by relay protection devices, automatic switches or fuses and equipped with electrical and telemechanics in accordance with established rules.

2.6.2. Maintenance, testing and measurement of relay protection devices, automation and telemechanics (hereinafter referred to as RZAiT) and their secondary circuits should be carried out, as a rule, by personnel of relay protection, automation and measurement services (laboratories): the Consumer's central, local or electrical laboratory. This laboratory must be registered with the State Energy Supervision Department for the right to test and measure in relay protection and automation devices. In cases where other services are involved in servicing certain types of RZAiT devices, service areas and responsibilities are delimited between them in accordance with local instructions.

For maintenance of RZAiT devices installed at the Consumer, it is possible to involve specialized organizations.

2.6.3. The maximum allowable loads of the power supply elements of the electrical network, according to the conditions for setting up relay protection and taking into account possible operating modes, must be agreed by the Consumer with the dispatching service of the power supply organization and periodically reviewed.

2.6.4. The settings of the RPA devices of the Consumer's communication lines with the power supply organization, as well as transformers (autotransformers) at the Consumer's substations, which are under the operational control or operational control of the energy supply organization's dispatcher, must be agreed with the relevant RPA service of the energy supply organization.

When choosing the settings, the selectivity of the action should be ensured, taking into account the presence of devices for automatic transfer of the reserve (hereinafter referred to as ATS) and automatic reclosing (hereinafter referred to as AR). In addition, when determining the settings for selectivity, the operation of technological automation devices and blocking of shop units and other mechanisms should be taken into account.

2.6.5. All settings of relay protection devices must be checked under the conditions of the minimum electrical load of the Consumer and the power supply organization for the current power supply scheme.

2.6.6. In the control current circuits, the selectivity of the operation of protection devices (fuses and circuit breakers) must be ensured.

Automatic switches, fuse blocks must be marked with the name of the connection and the rated current.

2.6.7. In operation, conditions must be provided for the normal operation of relay protection devices, electric automation, telemechanics and secondary circuits (permissible temperature, humidity, vibration, deviations of operating parameters from nominal, noise level, etc.).

2.6.8. RZAiT devices in operation must be constantly included in the operation, except for those devices that must be taken out of operation in accordance with the purpose and principle of operation, the mode of operation of the electrical network and the conditions of selectivity.

The planned decommissioning of RZAiT devices must be filed with a corresponding application and carried out with the permission of higher operational personnel (as appropriate).

In the event of a threat of incorrect operation, the RZAiT device must be taken out of operation without the permission of the higher operational personnel, but with its subsequent notification in accordance with local instructions and the filing of an application. At the same time, the relay protection devices remaining in operation must provide full protection of electrical equipment and power lines from all types of damage. If this condition is not met, temporary protection must be performed or the connection must be disabled.

2.6.9. Alarm and warning devices must always be in a state of readiness for operation and periodically tested.

Particular attention should be paid to the presence of operational current, serviceability of fuses and circuit breakers in the secondary circuits, as well as control circuits of switches.

2.6.10. When carrying out adjustment work in the RZAiT devices by a specialized organization, their acceptance is carried out by the Customer's personnel performing maintenance of the RZAiT devices.

If the Consumer does not have such personnel, they are accepted by the personnel of a higher organization.

Permission to commission newly mounted devices is issued by an entry in the log of relay protection, automation and telemechanics signed by the representative of this Consumer (higher organization) and the responsible executor of the commissioning organization.

2.6.11. Before commissioning the accepted RZAiT devices, the following technical documentation must be submitted:

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design materials adjusted during installation and commissioning (drawings and diagrams, explanatory notes, cable magazine, etc.) - by installation and commissioning organizations;

factory materials (technical description and operating instructions, certificates of electrical equipment and apparatus, etc.) - by the installation organization;

commissioning and testing protocols - by the commissioning organization or the Consumer's laboratory.

2.6.12. For each RZAiT device in operation, the Consumer must keep the following technical documentation:

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passport-protocol;

guidelines or instructions for maintenance;

technical data and parameters of devices in the form of maps or tables of settings (or characteristics);

principle, assembly or circuit diagrams.

The results of periodic checks during the maintenance of the device must be entered in the passport-protocol (detailed records, especially for complex RZAiT devices, are recommended to be kept in the journal of relay protection, electrical automation and telemechanics).

2.6.13. Relays, devices and auxiliary RZAiT devices, with the exception of those whose settings are changed by operational personnel, are allowed to be opened only by employees who carry out maintenance of these devices.

2.6.14. On the front and back sides of the panels and cabinets of RZAiT devices, alarms, as well as panels and control panels, there must be inscriptions indicating their purpose in accordance with the dispatcher names, and on the devices installed on them - inscriptions or markings according to the diagrams.

On the panel with devices belonging to different connections or different RZAiT devices of the same connection, which can be checked separately, clear dividing lines should be drawn or installed. It shall be possible to install a guard when testing individual devices.

2.6.15. The wires connected to the assemblies (rows) of the clamps must be marked according to the diagrams. On control cables, marking should be made at the ends, at the points of branching and intersection of cable flows, and on both sides when they pass through walls, ceilings, etc. The ends of the free conductors of the cables must be insulated.

2.6.16. The insulation resistance of electrically connected secondary circuits of RZAiT devices with respect to the ground, as well as between circuits for various purposes that are not electrically connected (measuring circuits, control current circuits, signaling), must be maintained within each connection at least 1 MΩ, and the output telecontrol circuits and 220 V power supply circuits of telemechanics devices - at least 10 MΩ.

The insulation resistance of the secondary circuits of the RZAiT devices, designed for an operating voltage of 60 V and below, powered from a separate source or through an isolating transformer, must be maintained at least 0,5 MΩ.

The insulation resistance of RPAiT devices circuits, telecontrol output circuits and 220 V power circuits is measured with a megohmmeter for 1000 - 2500 V, and for circuits of RPA devices with an operating voltage of 60 V and below and telemechanics circuits - with a 500 V megohmmeter.

When checking the insulation of the secondary circuits of RZAiT devices containing semiconductor and microelectronic elements, measures must be taken to prevent damage to these elements.

2.6.17. At each new switching on and the first preventive test of the RZAiT devices, the insulation relative to the ground of the electrically connected circuits of the RZAiT and all other secondary circuits of each connection, as well as the insulation between electrically unconnected circuits located within the same panel, with the exception of circuits of elements rated for an operating voltage of 60 V and below, must be tested with a voltage of 1000 V AC for 1 min.

In addition, a voltage of 1000 V for 1 min. the insulation between the conductors of the control cable of those circuits where there is an increased probability of a short circuit with serious consequences (gas protection circuits, circuits of capacitors used as a source of control current, etc.) must be tested.

In subsequent operation, the insulation of RZAiT circuits, with the exception of circuits with a voltage of 60 V and below, is allowed to be tested during preventive tests both with a voltage of 1000 V AC for 1 minute and with a rectified voltage of 2500 V using a megohmmeter or a special installation.

Insulation tests of RPA circuits with a voltage of 60 V and below and telemechanics circuits are carried out in the process of measuring its resistance with a 500 V megohmmeter (see clause 2.6.16).

2.6.18. All cases of correct and incorrect operation of RZAiT devices, as well as defects (malfunctions) identified in the course of their operational and maintenance, must be carefully analyzed by the maintenance personnel. All defects must be corrected by personnel.

2.6.19. RZAiT devices and secondary circuits must undergo maintenance, the volume and frequency of which are determined in the prescribed manner.

2.6.20. In the presence of high-speed relay protection devices and redundancy devices in the event of circuit breakers failure (hereinafter referred to as RPA), all operations to turn on lines, buses and electrical equipment after their repair or shutdown, as well as operations with disconnectors and air circuit breakers, must be carried out after the commissioning of the relay protection device. If it is impossible to enter them, it is necessary to introduce acceleration on backup protections or perform temporary protection (including non-selective).

2.6.21. Work in RZAiT devices must be performed by personnel trained and authorized to independently maintain the relevant devices, in compliance with labor safety rules when operating electrical installations.

2.6.22. When working on panels (in cabinets) and in control circuits, relay protection, electric automation and telemechanics, measures must be taken against erroneous shutdown of equipment. Work must only be carried out with insulated tools.

The performance of these works without executive schemes, and for complex RZAiT devices - without programs with specified volumes and sequence of work is not allowed.

Upon completion of the work, the serviceability and correctness of the connection of the current, voltage and operational circuits should be checked. Operational relay protection and control circuits should be checked, as a rule, by testing in action.

2.6.23. Work in RZAiT devices that can cause them to trip to disconnect connections (protected or adjacent), as well as other unforeseen effects, must be carried out on an authorized application, taking into account these possibilities.

2.6.24. The secondary windings of current transformers must always be closed to relays and devices or shorted. The secondary circuits of the current and voltage transformers and the secondary windings of the filters for connecting high-frequency channels must be grounded.

2.6.25. After the completion of scheduled maintenance, testing and post-emergency checks of RZAiT devices, protocols must be drawn up and entries made in the log of relay protection, electrical automation and telemechanics, as well as in the passport-protocol.

When changing the settings and diagrams of RZAiT, appropriate entries must be made in the journal and passport-protocol, as well as corrections made to the circuit diagrams and wiring diagrams and operating instructions for the devices.

2.6.26. Test installations for testing RZAiT devices during maintenance should be connected to socket outlets or shields installed for this purpose in the rooms of control panels, switchgears of the substation and in other places.

2.6.27. The front side of the panels (cabinets) and control panels, relay protection, electric automatics and telemechanics and devices installed on them must be periodically cleaned of dust by specially trained personnel.

Devices of open design, as well as the reverse side of these panels (cabinets) and consoles, must be cleaned by the personnel servicing the RZAiT devices, or the operational personnel who have been instructed.

2.6.28. Operational personnel must:

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control of the correct position of the switching devices on the RZAiT and control panels (cabinets), covers of test blocks, as well as the serviceability of automatic switches and fuses in the RZAiT and control circuits;

monitoring the status of RZAiT devices based on external signaling devices on the panels (cabinets) and devices;

testing of high-voltage circuit breakers and other devices, as well as devices for automatic reclosing, automatic transfer of the reserve and fixing devices (indicators);

exchange of high-frequency protection signals and measurement of controlled parameters of high-frequency teleswitching devices, low-frequency devices of automatic channels, high-frequency devices of emergency automatics;

measurement of unbalance current in the busbar protection and unbalance voltage in the open triangle of the voltage transformer;

clock factory of automatic oscilloscopes for emergency recording, etc.

The frequency of inspections and other operations, as well as the procedure for personnel, should be established by local regulations.

2.6.29. The transfer of remotely controlled equipment to autonomous control and vice versa should be carried out only with the permission of the dispatcher or the Consumer responsible for the electrical economy.

To disable the output telecontrol circuits at substations, common keys or disconnecting devices should be used. Disconnection of telecontrol or telesignaling circuits of individual connections should be carried out on detachable clamps or on individual disconnecting devices.

All operations with common telecontrol keys and individual disconnecting devices in the telecontrol and telesignaling circuits may be performed only at the direction or with the permission of the dispatcher (operational personnel).

2.6.30. On assemblies (rows) of control panels and panels (cabinets) of RZAiT devices, there should not be close proximity to clamps, the accidental connection of which can cause the connection to be turned on or off, short circuit (hereinafter referred to as short circuit) in the control current circuits or in the excitation circuits of the synchronous generator (electric motor, compensator).

2.6.31. When eliminating damage to control cables with a metal sheath or in case of their extension, the connection of the cores must be carried out with the installation of hermetic sleeves or using boxes designed for this. The specified couplings and boxes should be kept in a special journal.

Cables with PVC and rubber sheath should be connected, as a rule, using epoxy couplings or on adapter rows of clamps. For every 50 m of one cable, on average, there should be no more than one of the above connections.

In the case of control cables with insulation subject to destruction by air, light and oil, additional coatings must be applied to the sections of the cores from the clamps to the end grooves to prevent this destruction.

2.6.32. When operating personnel perform operations on the panels (in cabinets) of RZAiT devices using keys, contact pads, test blocks and other devices, tables of the position of the indicated RZAiT switching devices for the modes used should be used.

Operations for these switchings must be recorded in the operational log.

2.6.33. The personnel of the services of organizations that carry out maintenance of RZAiT devices should periodically inspect all panels and control panels, panels (cabinets) of relay protection, electrical automation, telemechanics, alarms. In this case, special attention is paid to the correct position of the switching devices (contact pads, knife switches, control keys, etc.) and the covers of the test blocks, as well as to the compliance of their position with the diagrams and modes of operation of the electrical equipment.

The frequency of inspections, determined by the local instructions, must be approved by the Consumer's responsible for the electrical equipment.

Operational personnel are responsible for the correct position of those RZA&T elements with which they are allowed to perform operations, regardless of periodic inspections by the personnel of the RZA&T service.

2.6.34. Recorders installed at substations or in switchgears with automatic recording acceleration in emergency modes, automatic emergency recording oscilloscopes, including their triggers, fixing devices (indicators) and other devices used to analyze the operation of RZAiT devices and to determine the location of damage to overhead power lines, must always be ready for action. Commissioning and decommissioning of these devices must be carried out on request.

See other articles Section Rules for the technical operation of consumer electrical installations (PTE).

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