Organization of switching in electrical installations of distribution networks 0.4 — 10 kV
Equipment working condition
The electrical equipment of distribution networks (power lines, transformers, switching devices, devices for relay protection and automation, etc.) can be in a state of: operation, repair, reserve, automatic reserve, powered. Obviously, the operating state of the equipment is determined by the position of the switching devices, which are designed to turn it off and on under voltage and in the operating mode.
The equipment is considered to be in operation if the switching devices according to it are turned on and a closed electrical circuit is formed between the source of power and the receiver of electricity. Valves and pipe restrictors, instrument transformers and other equipment solidly (without disconnectors) connected to the power source and live are considered to be in service.
If the equipment is disconnected from switching devices or is lined and prepared in accordance with the requirement of the Safety Rules for carrying out work, then regardless of the performance of repair work in it, it is currently considered to be under repair.
Equipment is considered to be in reserve if it is switched off by means of switching devices and it is possible to put it into operation with the help of these switching devices manually or with the help of a telemechanical device.
Equipment is considered to be in automatic reserve if it is switched off by switching devices, has an automatic drive for switching on and can be put into operation by the action of automatic devices. Equipment is considered energized if it is connected by switching devices to a power source, but not in operation (supply transformer without load; power line connected only on one side and disconnected on the other by a switching device, etc.).
Each relay protection and automation device can be in an on (commissioned) and off (output) state. A device for relay protection and automation is considered to be in operation if the output circuit of this device is connected to the control electromagnets of the device for switching on or off using disconnecting devices (overlays, operational contact jumpers).
A relay protection and automation device is considered disconnected if the output circuit of this device is disconnected by means of a disconnecting device from the control solenoids of the switching device.The transfer of equipment from one operational state to another occurs as a result of operational switching carried out by the personnel of operational field teams (OVB), as well as operational-repair and other employees admitted to operational work.
A change in the operating state of the equipment may also occur as a result of the activation of relay protection and automation devices in the event of various types of disturbances in the operation of distribution networks.
Changes in the working condition of electrical equipment distribution networks during normal operation, as well as during liquidation, accidents are managed by the dispatcher of the distribution network area, in the operational control of which this equipment and devices for relay protection and automation are located.
Operational control here means a method of equipment management, in which switching in electrical installations can be carried out only on the order of the dispatcher of the area of distribution networks and in the sequence determined by the dispatcher. And only in emergency cases, when a delay in removing voltage from an electrical installation is associated with a danger to human life or a threat to the safety of equipment (for example, in the event of a fire), operating personnel are allowed, in accordance with local instructions, to carry out of the necessary shutdowns of the equipment under the operational control of the dispatcher area of distribution networks, without receiving his order, but with subsequent notification to the dispatcher of all operations carried out at the earliest opportunity.
In some cases, depending on the availability of communication with the dispatcher of the distribution network area, territorial location of electrical installations, network diagrams and other conditions, the equipment with a voltage of 0.4 kV may be under the operational control of the master of the site (or other personnel , endowed with operational support rights) and at the same time in the operational management of the dispatcher area of distribution networks.
The operational support of the dispatcher of the distribution network area is also a way to manage the equipment, which is transferred to the operational management of the personnel from the lower levels. All switches with this control method are carried out only after obtaining the consent (permission) of the dispatcher. the area of the switching distribution networks, the sequence of which is determined independently by the personnel responsible for the transfer of the equipment.
As a rule, the equipment in the energy centers is under the operational control of the PES dispatcher. Therefore, the shutdown for repair and switching on of the lines feeding the distribution network, as well as the switching associated with changing the operating modes of the equipment in the energy centers, are carried out under the direction of the PES dispatcher. In this case, the sequence of operations for turning off and turning on the lines supplying distribution networks, the PES manager agrees in advance with the manager of the distribution network area, and then the manager of the distribution area networks gives an order to switch to RP, RTP, ZTP and TP of the distribution networks «to his» subordinate operational personnel.
The list of equipment in the operational control and in the operational control of the dispatcher of the PES and the dispatcher of the area of distribution networks, as well as transferred to the operational management of the personnel at the lower stages of the dispatcher control, is established by an order for the PES. In this way, each element of the equipment of electrical installations of distribution networks can be under the operational control of only one person: dispatcher of PES, dispatcher of distribution network area, site foremen, etc.
Power lines (communication lines) connecting the networks of two adjacent distribution networks and those that cross the territorial boundary between them are, as a rule, under the operational control of the dispatcher of one area of distribution networks and at the same time — in the operational jurisdiction of the dispatcher of another area of distribution networks.
In this method of operational relations, the principle of centralizing the management of the equipment is respected and the influence of the working states of the communication lines on the mode and reliability of the two distribution networks is taken into account.
The shift order is given by the dispatcher of the network distribution area to operational personnel directly or through communication means. The content of the order is determined by the dispatcher, who takes into account the complexity of the task, the reliability of communication facilities, the condition of the roads between electrical installations and other conditions that affect the execution of the order.
The order specifies the purpose and sequence of operations.When switching in relay protection and automation schemes, the name of the connection, the automatic device and the operation to be performed are called. The person who received the order is obliged to repeat it and receive confirmation that he understood the order correctly.
Such a procedure is recommended, as with repetition, mutual control and timely correction of an error, if made by the person giving or accepting the order, becomes possible.
Both participants in operational negotiations must clearly understand the sequence of planned operations and understand that their implementation is permissible according to the state of the circuit and the mode of operation of the equipment. The operating mode of the equipment should, as a rule, be checked before the start of switching, as well as during them (if possible), in order to prevent the occurrence of severe operating modes (overloads, voltage deviations from the nominal value, etc.). n. .).
The order received by the operational staff is recorded in the operational log, the sequence of operations is checked according to the operational diagram of the network section, on which the positions of the switching devices must be marked at the time of receiving the order. The second ATS person must be aware of the content of the received order if involved in the switchover.
The sequence of the upcoming operations should not raise doubts among the persons preparing for their implementation. It is forbidden for operational personnel to proceed with the execution of orders that are incomprehensible to them.
As practice shows, the dispatcher of the area of distribution networks should not receive a permit to prepare a workplace and a permit to work at the same time as issuing a switching order. A permit for workplace preparation and admission to work must be issued after the operating personnel have been notified of the completion of the switchover in accordance with the previously received order.
We also note the fact that if the order is received by the operational staff, he can no longer make any changes to it, as well as refuse to carry it out, except for cases where the execution of the dispatcher's order endangers people's lives and safety of the equipment. The operational staff notifies the dispatcher who issued the order to move about the refusal to fulfill the order (due to an unforeseen situation).