3.3. Testing of electrical networks with voltage up to 1000 V in electrical installations of consumers of electrical energy

CHAPTER 4 NORMATIVE AND TECHNICAL DOCUMENTATION IN ELECTRICAL INSTALLATIONS 4.1. Technical documentation Availability of complete and high-quality NTD in electrical installations is an important prerequisite for organizing and maintaining an appropriate level of electrical facilities. Her underestimation is fraught

10.1. General provisions

Switching is a change from one set of connections to another (IEC ST 50(151)-78).

The main document regulating the organization and procedure for switching, their implementation, switching when transferring connections from one bus system to another, when equipment is taken out for repair and put into operation after repair, etc., is the “Instruction for Switching in Electrical Installations” , approved by order of the Ministry of Energy of Russia dated June 30, 2003 No. 266.

Specified Document determines the order and sequence of switching in electrical installations with voltage up to and above 1000 V.

On the basis of this instruction, at power plants, substations, in electrical networks, instructions are developed for the production of switching, taking into account the features of normal and repair schemes for electrical connections of electrical installations, the design and composition of switchgear equipment, the features of RPA devices, and the order of operational maintenance of these objects.

The instruction of the power company on the operational switching of electrical installations is located at the workplace of the operational dispatch personnel.

The operating personnel of power plants, substations, electrical networks and power systems include:

shift supervisors of electrical workshops of power plants;

power unit shift supervisors;

duty electricians of power plants;

electricians on duty PS;

OVB staff.

Operational and repair personnel of electrical networks include repair personnel with the right to perform switching in electrical installations.

The operational managers in the shift are: the dispatcher of the unified power system, intersystem electrical networks;

power system manager;

dispatcher of the enterprise (district, section) of the electrical network;

shift supervisor (duty engineer) of the power plant.

Commissioned equipment is in one of the following operational states:

in operation, including in automatic reserve, under voltage;

in reserve;

under repair;

in conservation.

In the state of operation, the switching devices in the equipment circuit are turned on and a closed electrical circuit is formed or can be formed between the power sources and the power receiver.

Communication capacitors, RV, VT, OPN and other equipment, rigidly (without disconnectors) connected to the power source and under voltage, are considered to be in operation.

If the equipment is disconnected by switching devices and prepared for work, then it is considered to be under repair (regardless of the repair work performed on it).

Reserved equipment is considered to be equipment that is switched off by switching devices and it is possible to immediately put it into operation with the help of these switching devices.

The equipment is considered to be in automatic reserve if it is switched off only by switches or separators having an automatic drive to turn on, and can be put into operation by the action of automatic devices.

The equipment is considered to be energized if it is connected by switching devices to one voltage source (power transformer on the XX, power lines connected from the side of the substation supplying it, etc.). Disconnected from the network, but continuing to rotate, the SC with the AGP turned off is considered to be energized.

The relay protection and automation device is considered to be in operation if all output circuits, including the contacts of the output relays of this device, are connected to the control circuits that turn on or off the control electromagnets of the switching devices using overlays (blocks, keys).

The RPA device is considered disabled for maintenance (operational check), as well as for preventive maintenance on the device or in its circuits, if it cannot be put into operation due to a malfunction of the device itself or its circuits.

Operational switching is the transfer of equipment from one operational state to another.

The change in the operational state of the equipment at the substation is managed by the dispatcher, in whose operational control is the main equipment, RPA devices and various automatic devices. In urgent cases, with a clear danger to human life, etc., the equipment is turned off without the knowledge of the dispatcher, but with subsequent notification. Similar actions are allowed in case of a threat to the safety of equipment, for example, in case of fire.

Switching in an electrical installation is allowed to be performed by operational personnel who know its scheme, the location of equipment and RPA devices, who are trained in the rules for performing operations with switching devices and clearly represent the sequence of switching, who have passed the test of knowledge of the rules of technical operation, safety rules and production instructions. Admission to operational work is allowed after duplication at the workplace.

The list of persons admitted to conduct switching (with an indication of which electrical installations), as well as the list of administrative and technical personnel who control the implementation of switching, is approved by the head of the enterprise (organization).

The duty officer receives and issues a switching order in the following order:

having received an order to switch, writes it down on a “draft”, repeats it according to the record and receives confirmation from the dispatcher that the order was understood correctly;

writes the task to the operational log;

checks according to the operational scheme (layout diagram) the sequence of operations and, if necessary, draws up a switching form or prepares a standard switching form for use.

The purpose of the order received and the sequence of upcoming operations is explained to the second person, if he is involved in the switching.

Switching in electrical installations, with the exception of complex ones, can be carried out individually - with one person on duty in a shift, or by two persons - with two persons on duty in a shift or as part of an OVB.

10.2. Switch Orders and How to Execute Them

Before issuing an order for the production of switching, the operational manager is recommended to find out the state of the electrical installation circuit, the readiness of the operational personnel to make switches, the availability of a switching form (program), the presence of a controlling person, etc.

The switching order is given by the dispatcher directly to subordinate personnel orally or by telephone. The receiver of the switching order repeats the text to the one giving the order and writes it down in the operational log.

The order indicates the purpose of switching and the sequence of operations in the electrical installation diagram and in the relay protection and automation circuits with the necessary degree of detail, determined by higher-level operational and dispatching personnel.

At a permanently on duty substation, the switching executor is simultaneously given no more than one task for conducting operational switching, containing operations of the same intended purpose.

To the staff of the PSO servicing substations and distribution networks, in order to save time and rational use transport is allowed to issue several tasks for switching simultaneously with an indication of the order in which they are performed. The number of tasks given to one brigade is determined by the one who gives the order. Jobs are recorded in the OBE operational log in the order in which they are executed. The performance of each next task by the FSO personnel begins after informing the dispatcher about the completion of the previous task and only after receiving his permission to perform the next building.

When repairing damages in electrical networks with a voltage of 10 kV and below, it is allowed to perform the next tasks without prior notification to the dispatcher about the completion of the previous tasks.

The person who received the order must repeat it and receive confirmation that he understood the order correctly.

One of the recommended forms of receiving a task (instruction) for switching is to apply to the dispatcher with a pre-thought-out application, including the operational state of the scheme and the sequence of operations, and obtain the dispatcher's permission to perform them.

The received permission in the form of a task is recorded in the online log. If necessary, a switching form is drawn up or a standard form is filled out.

If the operational order is received by the personnel, then it cannot be changed or postponed by them: only the dispatcher or his immediate supervisor can change the order.

Switching to the PS can be performed by one or two persons. When two persons participate in the switching, the supervisor is appointed the senior in the shift or a person specially appointed and arrived at the substations, who, in addition to monitoring the correct execution of each operation, is also responsible for monitoring the switching. The lowest ranking person is the executor. Switching is the responsibility of both parties.

The procedure for personnel actions when switching according to the switching forms should be as follows:

at the place of the operation, the name of the electrical circuit and the name of the switching device are checked by the inscription. Performing an operation from memory without checking the inscription at the drive of the device is prohibited;

after making sure that the selected switching device is correct, the content of the operation is read out according to the form and then it is performed. When two persons participate in the switching, the operation is performed after it is repeated by the performer and the corresponding confirmation of the controller is received;

the completed operation is noted in the form in order to avoid missing the next operation;

the person performing the operation repeats its content and, having received the permission of the controlling person, performs the operation;

immediately after performing individual operations or verification actions, marks are made in the switching form about their implementation in order to exclude the possibility of skipping any operation;

before the beginning and at the end of switching operations, the switching form indicates the date and time of the beginning and end of operations.

The used form is crossed out and placed in the folder of used switching forms.

When switching, unnecessarily interruptions are not allowed.

In the switching form, the time of their completion is recorded. An entry is made in the operational journal about the execution of the order. Changes are made to the operational scheme or layout scheme. Then the person who received the order informs the dispatcher from whom the order was received about the execution of the order.

Higher operational and dispatching personnel give permission to switch to general view(without listing individual operations) after checking the possibility of their implementation according to the scheme, checking the operating mode of the equipment and carrying out the necessary regime measures.

10.3. The sequence of typical operations with switching devices when turning on and off VL, KL and transformers

Turning on VL and CL:

the open position of the switch is checked;

the bus disconnector is switched on;

the switch turns on.

Disabling VL and CL:

the switch is turned off;

the line disconnector is turned off;

the bus disconnector is switched off.

The sequence of operations in switchgear with withdrawable elements when switching on connections of overhead lines and lines:

Inclusion:

the circuit breaker trolley moves from the control to the working position;

the switch turns on.

Shutdown:

the switch is turned off;

checks if the switch is off;

the trolley with the switch is moved to the control or repair position.

The sequence of operations when turning on and off a three-winding transformer (autotransformer):

Inclusion:

HV busbar and transformer disconnectors are switched on;

MV busbar and transformer disconnectors are switched on;

LV busbar and transformer disconnectors are switched on;

the switches on the HV, MV and LV sides of the transformer are switched on.

For some types of autotransformers that have insufficient dynamic short circuit resistance on the high voltage side, the following sequence of switching on their switches is recommended: switches are switched on MV, LV, and then HV.

Shutdown:

the switches are switched off on the side of the LV, MV and HV transformers;

LV transformer and bus disconnectors are switched off;

MV transformer and bus disconnectors are switched off;

HV transformer and busbar disconnectors are switched off.

10.4. Sequence of operations when switching on and off electrical circuits

In electrical circuits, operations with switching devices are performed in a certain sequence and, in addition, with the prevention of emergencies and damage to electrical equipment, which is ensured by the correct sequence of operations.

When an electrical circuit with switches is turned off, the first operation is to open the switch, breaking the current circuit and removing voltage from individual elements of the electrical circuit (power lines, transformers, etc.). Switch inputs can remain energized on the side of the busbars.

The disconnecting sequence of the disconnectors is as follows: first, the linear (transformer) disconnectors are disconnected, and then the bus disconnectors.

When switching on electrical circuits, first turn on bus disconnectors to the corresponding busbar system, and then linear (transformer).

In indoor switchgear 6-10 kV, in which line (cable) disconnectors are located close to the floor and are not separated from the control corridor by a solid protective wall, operations with them are dangerous for personnel. In this case, when disconnecting the line, it is recommended to first disconnect not linear, but bus disconnectors located at a great distance from the operator.

When switching on the electrical circuit, the operations with the switches are performed last.

Automatic devices (AR, ATS, etc.) are taken out of operation before the circuit breaker is turned off, and put into operation after the circuit breaker is turned on.

In addition to following the sequence of switching on and off operations, so-called test actions in electrical circuits are necessary, in which the circuits and their modes of operation do not change, but only information about their state is given.

Verification actions include checks of the operating modes of the substation and equipment carried out before the start of switching, as well as in the process of their implementation.

Based on the results of such checks, conclusions are drawn about the possibility of switching; the occurrence of overload modes of equipment operation, voltage deviations from the nominal value, etc. is prevented.

When switching, the loads of disconnected (switched on) circuits, the position of switching devices, stationary grounding switches, the absence of voltage on live parts before their grounding are subject to verification.

It is obligatory to check the position of the circuit breakers at their place of installation, if, after opening the circuit breakers, operations are to be carried out with disconnectors or separators of these circuits.

In the switchgear, the disconnected position of the circuit breaker is checked before each operation of moving the trolley in the switchgear cabinet from the working to the test position, and vice versa.

Checking the position of the circuit breaker according to the indications of signal lamps of the mimic diagram of measuring instruments (ammeters, voltmeters, wattmeters) is allowed to be carried out when the circuit breaker is turned off without carrying out further operations with disconnectors, turning off the circuit breaker with subsequent operations with disconnectors using a remote drive, when switching on under load lines, transformer, when applying and removing voltage from the tires. In such cases, it is not necessary to check the actual position of the circuit breaker at its installation site, if it is clear from the signal lamps and measuring instruments that the operation with the circuit breaker has taken place.

The output for repair of the line, taking into account the verification actions, is carried out in the following sequence (Fig. 10.1):

check the possibility of disconnecting the line according to the mode of operation of the network section (PS);

at substation A, the line switch is turned off and the ammeter checks for the absence of a load on it;

at Substation B, they check the absence of load on the line and turn off its switch;

in the switchgear, the off position of the line switch is checked and its line disconnectors are turned off;

check the disconnection of each phase of the disconnectors;

at the substation A in the switchgear, they check that the line switch is in the off position;

turn off the line disconnectors and check the position of each phase of the disconnectors.

After checking the absence of voltage on the line, protective grounding is applied on both sides of it. When stationary grounding switches are turned on, the position of the grounding switch of each phase is checked.

The sequence of operations when disconnecting the power transmission line is as follows: disconnect the automatic reclosure device and the line switch, linear and bus disconnectors.

The sequence of operations when switching on the power transmission line is as follows: turn on the bus disconnectors to the corresponding busbar system, then the line disconnectors, the circuit breaker and the automatic reclosure of the line.

Turning off a dead-end power line begins with turning off the switch on the powered substation, while checking the readiness of consumers to turn off the line. Then they check the absence of load on the line and turn off its switch from the side of the supply substation.

Turning on the line under voltage and load is performed in the reverse order.

The sequence of operations when switching off and on transit lines and long-distance transmission lines (voltage 330 kV and above) is established by the dispatcher.

The switching on and off of one of the paired lines, when the other is disconnected by line disconnectors, is carried out in the usual sequence provided for a single line. The inclusion of one of the paired lines, if the other is in operation, is carried out with the disconnection of the line in operation. To do this, turn off the live line switch on the load side, turn off the coupled line switch on the supply side, turn on the line disconnectors on both sides of the line being switched on, turn on the switch on the supply side and turn on the switches of both lines on the load side.

Disconnection of one of the paired lines, when both lines are on and under load, is performed with the disconnection of the paired lines. To do this, turn off the switches of both lines on the load side, turn off the switch of the paired lines on the supply side, turn off the line disconnectors on both sides of the line being switched off, turn on the switch on the supply substation, apply voltage to the line remaining in operation, close the line under the load by turning on its switch at the consumer .

The three-winding transformer (autotransformer) is disconnected in the following sequence: the switches are turned off on the LV, MV and HV sides, the transformer and busbar disconnectors are switched off on the LV side, and then in the same sequence on the MV and HV sides.

To turn on the transformer, it is necessary to turn on the busbar and transformer disconnectors on each of their three sides, then turn on the HV, MV and LV switches.

If an arc quenching reactor is connected to the neutral of the 35 kV transformer winding, then its shutdown should begin with the shutdown of the reactor. Disconnection from the network of the winding of the only transformer of the substation with an arc-suppression reactor connected to the neutral or the only line extending from the substation with an arc-suppression reactor without disconnecting this reactor is dangerous due to the possible overlapping of the 35 kV equipment insulation.

10.5. Switching during the elimination of technological violations

The elimination of technological violations in electrical installations is carried out in accordance with the instructions of energy enterprises, drawn up on the basis of instructions from a higher operational management body.

Switchovers during the elimination of accidents and technological disturbances (incidents) are carried out in the same order and sequence as set out in the industry instructions indicated above in paragraph 10.1 and in the instructions of energy enterprises. At the same time, deviations from the requirements of safety rules are not allowed.

When inspecting the RPA and alarm panels, mark with chalk or in another way all the triggered indicator relays and the passed signals about the operation of devices, record which RPA and A devices have worked. Before turning on the equipment again, the signals are acknowledged, the flags of the indicating relays are raised. It is not allowed to restart the switched off equipment without acknowledgment of the indicator relays.

If it is impossible to acknowledge the signals, in the absence of actual signs of operation of RPA devices and the conditions for their operation, the decision on the possibility of switching on the equipment that has been switched off is made by the operational manager in charge of the equipment that has been switched off.

When eliminating technological disturbances or in order to prevent them, it is allowed to make switching without the use of switching forms, followed by an entry in the operational log after the elimination of a technological violation.

When eliminating technological violations in the event of a malfunction of the operational blocking devices, failure of switches or other switching devices to turn off (turn on), the operating personnel may be given permission to independently release the indicated blocking devices after a thorough check of the circuit and the correctness of the previous operations. Permission to release in these cases is given by the operational manager in the change of enterprise (power plant, electric network).

When eliminating technological disturbances in the absence of communication with the dispatcher, the operational personnel independently perform operations with switching devices and RPA devices in the cases provided for by the instructions of energy enterprises for the elimination of technological violations. He reports the operations performed to the dispatcher, in whose operational control or operational jurisdiction these devices and devices are located, as soon as communication is restored.

10.6. Switchovers during commissioning of new equipment and testing

The energization of newly commissioned electrical installations and equipment, as well as special tests of equipment, are carried out according to programs agreed with the relevant production services and approved by the head of the power company. The programs are drawn up in accordance with the regulation on the procedure for the development, coordination and approval of test programs for thermal, hydraulic and nuclear power plants, in power systems, thermal and electric networks.

Switching in electrical installations associated with the inclusion of newly introduced equipment or special tests are carried out according to switching forms compiled in accordance with approved programs, under the guidance operational manager enterprise or power system (depending on the nature of the tests). If special tests are carried out for two or more shifts, it is recommended to draw up the switching forms in advance - before the start of the tests.

10.7. The sequence of operations when switching off and on electrical circuits at the substation, performed according to simplified schemes

On substations made according to simplified schemes, as a rule, there are no busbars and switches on the HV side, but there are always switches on the MV and LV sides. Such substations are connected according to the “transformer-line” block scheme with separators, two blocks with separators and a jumper on the side of the lines, according to the bridge scheme with separators (or a switch) in the jumper, etc.

An important role in switching is played by jumpers when transformers are taken out for repair, as well as during automatic shutdowns of equipment and the occurrence of post-emergency modes of operation.

The line disconnection sequence on two-transformer substations is as follows: on one of the substations, the switch and linear disconnectors are turned off, on the other substation, linear disconnectors, while the voltage is removed from the line.

Turning on the line: on one substation, line disconnectors are turned on and then voltage is applied using a switch to check the serviceability of the line and the absence of grounds on it. Supplying voltage to the line by switching on disconnectors at another substation is fraught with danger to personnel. Then turn off the switch of the first line. On another substation, a bar or a voltage indicator checks for the absence of voltage at the input of the line and turns on the line disconnectors to apply voltage to it.

Turning off the transformer T1 for repair is carried out in the following sequence:

transfer the power supply of the auxiliary load of 0.4 kV completely to another T2s transformer. n; turn off the breaker and remove the fuses from the 0.4 kV side of the T1s transformer. n, to exclude the possibility of reverse transformation;

adjust the arc extinguishing reactor for the total charging current of the lines outgoing from the busbars of 10 kV and turn off the disconnector of the arc extinguishing reactor;

ARCT transformers T1 and T2 are switched from automatic to remote control. The on-load tap-changer of transformer T1 is transferred to a position identical with the position of transformer T2;

disconnect the ATS of 110 kV separators, the automatic reclosure of the T1 switch from the LV side and the ATS of the sectional switch;

turn on the 10 kV section switch and, after checking the load on it, turn off the switch from the LV T1 side;

switch ARCT transformer T2 from remote to automatic control;

OLTC of transformer T1 is set to the position corresponding to the rated voltage and the ARCT is turned off;

check whether the switch T1 is off on the LV side, and the trolley with the switch is set to the repair position;

include a grounding disconnector in the neutral of the 110 kV winding of transformer T1;

remotely turn off the separators of the transformer T1;

disconnect line disconnectors and disconnectors in the jumper.

Turning on the transformer T1 is carried out in the following sequence:

check whether the short circuit on the line of this transformer is disconnected;

check whether the disconnector is turned on in the neutral winding of the transformer T1;

check whether the separators are disconnected from the LV winding side, and then turn on the disconnector from this side;

when the switch is in the off position on the side of the LV winding, move its trolley to the control position and connect the electrical connectors in the cabinet;

check the position of the tap changer of the transformer T1, which must correspond to the rated voltage;

turn on the separators on the HV side and by turning on the line disconnectors, the transformer T1 is energized;

after checking the full-phase switching on of the transformer under voltage, which is established visually by the position of the knives of the three phases of the disconnectors and separators, the grounding disconnector in the neutral of the 110 kV winding is turned off;

roll into the working position the trolley with the circuit breaker on the LV side;

switch the ARCT of the T2 transformer from automatic to remote control;

switch to the remote control of the ARCT of the transformer T1 and set its on-load tap-changer to the position in which the on-load tap-changer of the operating transformer T2 is located;

turn on the switch on the LV side and check the load distribution between the transformers T1 and T2, then turn off the 10 kV sectional switch;

include ATS of a 10 kV sectional circuit breaker, ATS of a circuit breaker on the LV side and ATS of 110 kV separators;

install fuses and turn on the breaker on the 0.4 kV side of the T1 transformer;

turn on the arcing reactor and restore the normal mode of capacitive current compensation.

Further, at the branch substation, the transformer separators and line disconnectors are turned off, after which the line is put into operation, and the disconnected transformer is prepared for repair. When the transformer is turned on, the voltage is again removed from the line by turning off the switches on the supply substation. At the branch substation, transformer separators and line disconnectors are turned on, then voltage is applied to the line and transformer by turning on the switch on the supply substation and the line is switched on in transit.

Shutdown of the line for repair is carried out in the following sequence:

at the branch substation, the sectional separators are switched off in the ATS jumper and the auxiliary load power is transferred from the transformer T1sn to T2sn;

disconnect the ATS of the sectional switch;

turn on the sectional switch and immediately turn off the switch on the LV side of the transformer T1. At the first and second substations, the switches are turned off, and then the line disconnectors;

disconnected line is grounded.

The line is turned on after repair in the following sequence:

remove protective grounding from all sides of the line;

on the substation include linear disconnectors;

on the first substation, the switch is turned on, and the switch on the other side of the line includes it in transit and checks for the presence of a load;

restore the normal circuit on the second PS.

10.8. The sequence of operations at the substation with two bus systems when one of them is taken out for repair

Necessary condition transfer from one bus system to another is the equality of voltages, which is achieved by turning on

SHV connecting both bus systems. At the same time, SHCB shunts each pair of busbar disconnectors belonging to one bay during transfer. In this case, the inclusion of some bus disconnectors while the others are on, as well as the disconnection of one of the two disconnectors of the transferred connection connected to both busbar systems, does not pose a danger, since the SHV circuit shunting them has negligible resistance and, accordingly, a small voltage drop.

The sequence of bringing the busbar system into repair is connected, first of all, with the need to release it by transferring the connections from the busbar system being taken out for repair to the busbar system remaining in operation.

Switching is performed in the following sequence:

include SHV;

differential protection of tires is transferred to the mode of operation "with violation of fixation" of connections;

turn off the circuit breakers installed in the control circuits of the SHV and its protections;

disable autoreclosing of tires;

check in the switchgear whether the SHV and its disconnectors are turned on;

include bus disconnectors of all transferable connections to the II busbar system and check whether each of them is reliably connected;

disconnect the bus disconnectors of the transferable connections from the bus system I deduced for repair and check the position of each disconnector;

on the control panel switch the power supply of voltage protection circuits, automatic devices and measuring instruments to VT II of the busbar system, if it does not switch automatically;

turn on the circuit breakers in the control circuits of the SHV and its protection, check if there is no load on the SHV, and turn it off, removing the voltage from the I busbar system;

include autoreclosing tires.

Now that the I busbar is on standby, the following is done to take it out for repair:

a poster “Do not turn on - people are working” is hung on the control key of the SHV;

in the switchgear, they check whether the SHV is in the off position and turn off its busbar disconnectors I of the busbar system;

disconnect the bus disconnectors TN I of the bus system and remove the fuses (turn off the circuit breakers) from the side of its LV windings. The cabinet where the fuses (knife switches) are located is locked and a poster “Do not turn on - people are working” is hung on it;

lock the drives of all busbar disconnectors I of the busbar system. Posters are posted on the drives “Do not turn on - people are working”;

check whether there is no voltage on the current-carrying parts, where protective grounding must be applied. Include stationary grounding switches or impose portable grounding where there are no stationary grounding switches;

carry out measures to ensure safe working conditions for maintenance personnel (install fences, hang posters, etc.);

allow repair crews to work.

At the substation, where bus disconnectors have electric motor drives with remote control, it is allowed to transfer connections from one bus system to another one by one for individual connections.

To turn on the I busbar system and transfer part of the connections to it, do the following:

remove temporary fences and remove portable posters posted at the work site;

remove prohibition posters and locks from bus disconnector drives;

turn off stationary grounding switches (remove portable grounding);

include disconnectors ShSV;

include disconnectors TN I of the busbar system. Remove the poster from the cabinet and install the fuses (turn on the knife switch) on the side of the LV TN I busbar system;

check whether the SHV protections have minimum current and time settings and whether the trip protections are enabled. The control current voltage is applied to the SHV drive.

Then the I bus system is tested with voltage, for which the SHV is remotely turned on and the presence of voltage on the I bus system is checked using voltmeters.

To transfer connections to the I busbar system, perform the following operations:

the operating current voltage is removed from the SHV drive, the bus auto-reclosing is turned off;

check in the switchgear whether the SHV is turned on, and transfer part of the electrical circuits from II to I bus system in the sequence discussed above;

operating current voltage is applied to the SHV drive, the SHV is turned off;

the differential protection of the tires is switched to the normal mode of operation, the auto-reclosing of the tires is turned on.

10.9. Transfer of connections from one busbar system to another without SHV ​​in switchgear

The main condition for such a transfer is the potential equality of both busbar systems, which is achieved by switching switches on both busbar systems at bays with two switches per circuit.

The sequence of operations for such a transfer is as follows: turn on the second switches of two or three connections, having two switches per circuit, and use ammeters to check the load distribution over the phases of the switches on;

switch the differential current protection of the tires to the operating mode "with violation of fixation";

remotely turn on bus disconnectors for both busbar systems of one connection;

remove the voltage of the operating current from the drives connected to I and II of the busbar system of the disconnectors of the base connection;

check the position of the bus disconnectors at the place of their installation;

turn on remotely or manually the disconnectors of the connections transferred to another busbar system and check their actual position;

disconnect the bus disconnectors of the transferable connections from the busbar system to which the connections were switched on before the transfer;

check the actual position of the disconnectors;

check the presence of voltage on the RPA devices of the transferred connections;

operating voltage is applied to the drives of the bus disconnectors I and II of the busbar systems of the base connection and remotely disconnects its disconnectors from both busbar systems;

turn off, according to the accepted fixation, the second switches of the connections having two switches per circuit;

disable the breaker failure and busbar protection for switching in the current and operational circuits of these devices;

check the protection of the tires under load and put them into operation according to the normal scheme;

included in the work of the ROV.

10.10. Bringing circuit breakers into repair and putting them into operation after repair

The output of circuit breakers for repair, depending on the scheme of the substation and the number of circuit breakers per circuit, is carried out:

with any substation scheme and one switch per circuit - by disconnecting the connection for the entire time of repair, if this is permissible according to the network operation mode;

in case of a scheme with two busbar systems and one switch per circuit - by replacing the connection switch with an SHCB;

in the case of a scheme with two working and bypass busbars and one switch per circuit - replacing the connection switch with a bypass switch;

with a polygon scheme, one and a half, with two switches per circuit - by turning off the connection switch being taken out for repair and removing it from the circuit using disconnectors;

in the case of a bridge circuit with a switch and a repair jumper on disconnectors for repairing a sectional switch, by switching on the jumper on the disconnectors and removing the sectional switch from the circuit using disconnectors in its circuit;

To replace an electrical circuit switch with an SHV, two disconnections are required: one to disconnect the switch and install specially prepared jumpers from pieces of wire instead, the other to remove the jumpers and connect the switch.

When replacing a circuit breaker with a bypass switch, all switching is performed without disconnecting the circuit and releasing the operating busbar.

Ring and one-and-a-half circuits of the substation make it possible to bring any circuit breaker into repair and put it into operation after repair without disconnecting the electrical circuit.

When replacing an electrical circuit breaker with a SHV, the main operations are as follows:

turn on the SHV and all circuits, except for the one whose switch must be taken out for repair, are transferred to one working bus system;

to check the protection with operating current when they are transferred from one circuit breaker to another, the relay protection and automation devices are taken out of operation in turn and switched from the CT of the circuit breaker to be repaired to the CT SHCB;

the action of protections in the control current circuits is switched to SHV;

protections are put into operation and tested to turn off the SHV, while the inclusion of the SHV is carried out by the action of the automatic reclosure.

In any order, it is impossible to start switching from the busbar differential protection, if by this time no other protections act on the shutdown of the SHCB, since the buses on which the electrical circuit is connected with the circuit breaker to be repaired will remain unprotected until the moment of switching to the CT SHCB of any circuit protection.

After switching the protections to the SHV, the electrical circuit is turned off on both sides and grounded. The switch to be removed for repair is disconnected and pre-prepared jumpers from wires are installed in its place, thus restoring the electrical circuit.

The circuit is put into operation by turning on the SHV, having previously removed the protective grounding and including the circuit on the backup (I) busbar system.

When the electrical circuit is connected to one busbar system and works through SHV, it cannot be allowed to transfer connections from one busbar system to another without switching protections along the current circuits, since this is due to a change in the direction of the current in the CT SHV, which can lead to failure or malfunction not only busbar differential protection, but also all other types of differential and directional protection.

When commissioning after repairing a circuit breaker, the main operations are as follows:

turn off the electrical circuit, the switch of which is replaced by SHV, on both sides and ground;

remove the jumpers installed instead of the circuit breaker, and the breaker that has come out of repair is connected to the tires along its the usual pattern;

external inspection check the correct connection of the tires to the apparatus;

after completion of work, all protective grounds are removed, line and bus disconnectors are turned on for the backup bus system I and the electrical circuit is put into operation by turning on two switches - one that has been repaired and one that has been repaired;

relay protection devices are taken out of operation one by one and their current circuits are switched from CT SHCB to CT of the circuit breaker put into operation;

protection voltage circuits are switched to the corresponding VT. The action of protections for operational circuits is transferred to the circuit breaker;

protections are checked under load and tested for opening the circuit breaker with the inclusion of its automatic reclosure;

protection and automation devices are put into operation;

restoring the normal scheme of the primary connections of the switchgear with a fixed distribution of electrical circuits over the buses;

busbar protection is switched to the mode of operation with the accepted distribution of connections.

When replacing the circuit breaker with a bypass breaker, the main operations are as follows:

by turning on the bypass switch with the minimum settings on its protection and the switched on differential busbar protection, as well as the switched on start of the breaker from the protection, they test the bypass busbar system with voltage (if the bypass switch was turned off and its disconnectors are connected to the bypass busbar system and the working one, from which this electrical chain);

after checking the presence of voltage on the bypass busbar system, the bypass switch is turned off. On the protections of the bypass switch, the settings of the circuit protections are set;

voltage is applied to the bypass bus system by turning on circuit breakers, the switch of which is taken out for repair;

using test blocks, the TT circuits of the bypass switch are introduced into the busbar differential protection circuit;

turn on the bypass switch with the settings on its protections corresponding to the settings of the electric circuit protections, and immediately turn off the switch being taken out for repair;

disabling the differential protection of the tires and excluding the TT circuits of the disconnected circuit breaker from its circuit;

check the serviceability of operational circuits and turn on the breaker;

The circuit breaker to be removed for repair is switched off on both sides by disconnectors and grounded.

When commissioning an electrical circuit breaker using a bypass breaker, the main operations are as follows:

remove protective grounding from the repaired circuit breaker;

circuit breakers of power transformers are tested by turning on the transformer energized from the side of the MV or LV windings. To prevent false operation of the busbar differential protection, the CT secondary circuits of the electrical circuit whose circuit breaker is being tested by voltage must be disconnected from the busbar differential protection and grounded;

since at the time of repair all relay protection devices were turned off on the switch, when it is put into operation, temporary protections are connected to it, checked from an external source of primary current;

CT circuits of the circuit breaker being put into operation are connected to the busbar differential protection circuit using test blocks;

in the switchgear, they check whether the switch being put into operation is turned off, and turn on the disconnectors on both sides of it;

turn off high-speed differential circuit protection;

turn on the circuit breaker, check for load, and then turn off the bypass breaker;

disabling the differential protection of the tires and removing the TT circuits of the bypass switch from its circuit;

protection is checked under load and put into operation;

the main circuit protections are switched off in turn and transferred from the bypass switch to the switch put into operation;

protections are checked under load and put into operation, and temporarily switched on protections are turned off; put into operation the automation devices;

disconnect the circuit breakers from the bypass busbar.

In ring type circuits, electrical circuits are connected to busbar sections between two adjacent circuit breakers. The disconnectors in the circuit are intended for operations related to the production of repair work. Conclusion for repair of any switch is carried out without disrupting the operation of electrical circuits.

A feature of ring-type circuits is that in case of damage to the electrical circuit, it must be turned off by two switches. This determines the placement in the CT circuit and the connection of RPA devices to them.

A feature of bridge-type circuits are CTs in the repair jumper. The jumper is switched on when the sectional switch is taken out for repair, and the main differential-phase protection of both protected lines is switched on at the CT.

If there are switches in the bridge circuit in the transformer circuits (and not separators with short circuits), then to bring these switches into repair (with the installation of repair jumpers instead of the switch brought out for repair), operations are carried out with relay protection devices on the supply substations, namely: backup protection The lines are configured in such a way that they selectively open the line breaker in the event of a fault in both the line itself and the transformer.