RU2574819C2 - System for automatic voltage reduction limitation (avrl) - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to electric power production. Claimed system comprises the AVRL device(s). Said system comprises the cutoff voltage comparison unit, cutoff time lag unit, connections set consecutive disconnection unit, cut-in time lag unit and separate connections consecutive actuation unit. Note here that the system input incorporates extra connected in series electric network mode determination unit, analysis unit, unit for determination of connections activated by AVRL and AVRL devices setting master unit. Note that the network mode determination unit defines the voltage across the buses of substations. Analysis unit defines the substations for AVRL devices to be mounted thereat. Said unit for determination of connections sets the priority of connections. Said devices setting master unit sets the settings by voltage and cutoff time.

EFFECT: higher efficiency of the system operation.

2 dwg, 3 tbl

Description

The invention relates to the electric power industry and can be used in emergency automation of electric networks of 35-220 kV to prevent unacceptable under conditions of stability voltage reduction on substation buses in post-emergency conditions.

Known automatics of limiting voltage reduction on substation buses, made on the basis of microprocessor relay protection terminals in the form of automatic devices for shutting off consumers, permission blocks for automatically re-enabling feeders, communication switch between units [1].

The prototype provides increased reliability and the ability to quickly reconfigure. However, the prototype does not offer an integrated approach to the organization of automatic voltage reduction limit (AOSN), does not determine the need and location of AOSN devices at substations, does not consider the reliability of power supply from the point of view of the social significance of consumers. As a result, an increase in reliability within each individual substation does not lead to an optimal AOSN within the energy district.

The technical result of the proposed technical solution is to increase the efficiency of the system to automatically limit the voltage reduction.

The specified technical result is achieved by the fact that in the system of automatic limitation of voltage reduction in electric networks of 35-220 kV, containing the device (A) AOSN, including a unit for comparing with the disconnecting voltage, a unit for holding the time for disconnecting, a unit for sequentially disconnecting connection groups, a unit for comparison voltage, block delay time for switching on, block for sequential switching of individual connections, a series-connected block for determining the modes of electric tion network analysis unit, a determination unit connections connected under the AOSN block setpoint voltage drop protection device, wherein the determining unit electric network modes is configured to determine the voltage on the tire in the normal power region substations, repair, and post-emergency conditions; the analysis unit is configured to determine substations on which it is necessary to install AOSN devices if the voltage on the tires does not exceed 0.77 of the rated voltage; the unit for determining the connections connected under the action of AOSN is configured to prioritize the connections depending on the social significance of the consumers of electric energy and the presence of an automatic reserve input (ATS) on the substation 6, 10, 20 kV buses; the unit for setting the settings of the AOSN devices is configured to set the voltage and time of disconnection and on-time taking into account the connection groups.

The introduction of these additional units and the sequence of their connection allows to increase the efficiency of the system of automatic limitation of voltage reduction, namely optimization of emergency automation of electric networks 35-220 kV in terms of minimizing the number of AOSN devices at substations and increasing the reliability of power supply by minimizing the number of disconnected consumers of electric energy needed to maintain an acceptable voltage level on substation tires.

The essence of the proposed technical solution is illustrated by the functional diagram of the system. In FIG. 1 is a communication diagram between the blocks of the proposed system, which shows a series-connected block 1 for determining the modes of the electric network, block 2 analysis, block 3 for determining the connections connected under the action of AOSN, block 4 for setting the settings of AOSN devices, AOSN device including block 5 for comparing with the disconnection voltage and unit 8 for comparing with the voltage of switching on the connections, blocks 6 and 9 of the time delay for disconnecting and switching on the connections, block 7 for sequentially disconnecting the groups of connections and block 10 lnly including individual connections.

The system is developed on the basis of microprocessor equipment and operates as follows.

In block 1 of determining the modes of the electric network, the normal, repair and post-accident modes of the region of the electric network of substations that are in one transit are determined and the voltage values in the nodes (on the substation buses) of the considered network section are determined using computer equipment and specialized software.

Initial data:

- the results of control measurements of flow distribution, loads and voltage levels (hereinafter referred to as control measurements) made in electric networks according to the “Rules for Technical Operation of Consumer Electrical Installations” [2] twice a year, every third Wednesday of June and December (billboards, ASKUE);

- parameters of the electric network for drawing up the calculation model of the considered region of the power system (active, reactance and capacitive conductivity of power lines; active, reactance, capacitive conductivity and transformation ratios of transformers and autotransformers; the values generated by the installed active and reactive power generators in the network; the values generated by the installed network synchronous reactive power compensators; conductivity values of reactor in and batteries of static capacitors installed in the network);

- information on the presence of the automatic connection of a reserve (ATS) at the considered connections through the distribution network of 6 kV, 10 kV and 20 kV and the place of its installation.

In block 2 of the analysis, the analysis of the obtained voltage values is carried out and a decision is made on the need and installation locations of AOSN devices. In the case of lowering the voltage levels on the high-voltage busbars of substations in repair and post-accident conditions to a value of 0.77 × Un and below (according to the “Methodological guidelines for the stability of power systems” [3]), installation of AOSN devices at these substations is required.

In block 3, the connections of the selected substations that are connected under the action of AOSN are determined, taking into account the load and social significance of consumers who are powered by these connections. Connections are divided into four groups depending on the social significance of consumers (power consumers):

- the first group of interconnections - interconnections that provide power to the least responsible consumers, the temporary blackout of which will not lead to damage to equipment, a threat to human life and health, or a shutdown of the technological process at an enterprise (life, gardening associations, summer residences, etc.);

- the second group of interconnections - interconnections that supply food to more responsible consumers compared to the first group, which de-energization will not cause damage to equipment, threat to human life and health, or stop the technological process at the enterprise (industry, sports grounds, schools, kindergartens, etc. .);

- the third group of interconnections - interconnections that supply power to more responsible consumers compared to the second group, interruption of power supply of which leads to disruption of the normal activity of a significant number of residents (city administrations, research centers, etc.);

- the fourth group of interconnections - interconnections that provide power to the most critical consumers, the interruption of power supply of which can lead to a danger to people's lives, disruption of the functioning of especially important elements of the urban economy, damage to equipment (factories, hospitals, clinics, boiler rooms, etc.).

Connection of connections under the action of AOSN devices must be carried out in accordance with the following rule: if the controlled substation buses are powered by two independent power sources, then only connections of that section of the low voltage (medium voltage) busbars of the substation should be connected under the action of AOSN devices, which in normal operation is connected through the power transformer (autotransformer) circuit to the high voltage side bus, the voltage level at oh decreased to unacceptable stability under the terms of the values as shown in FIG. 2.

The share of the load connected under the action of AOSN is established by regulatory documents (typical value - 60%). The load volume of each of the four groups of connected connections should be 25% of the total value of the load connected under the action of AOSN devices.

The first under the action of AOSN devices are connected connections with the presence of ATS according to the following rules:

- connections with the presence of ATS must be connected to the first group of settings of AOSN devices;

- the priority when choosing the connections connected under the action of AOSN devices with the presence of ATS must be given to the connections, the load of which under the action of the ATS switches to the connections, the load of which does not affect the voltage level of the considered section of the power system;

- within the limits of one substation, the connection, the load of which, in the event of its disconnection, by the action of the ATS switches to the connection with the load affecting the voltage level of the considered node of the power system, must be connected under the action of AOSN devices only together (in one corresponding group) with its backup accession;

- the action of the ATS should not lead to an overload of network electrical equipment.

Under the action of AOSN devices, it is forbidden to connect transformers of the auxiliary needs of the substation due to the fact that through these transformers the relay protection devices and a number of auxiliary needs of the substation are supplied.

If there is an automatic reclosure device (AR) on the connections connected to the AOSN device, it is necessary to block the reclosure of these connections when the AOSN devices are triggered to exclude the repeated connection.

AOSN devices are characterized by the following principle of operation. When the voltage level at the controlled high-voltage busbar system of the substation decreases below the permissible level U1 (block 5) with a time delay t1 (block 6), a command is generated to disconnect the connections connected to the AOSN device (block 7). When disconnecting the substation connections, the voltage level returns to the allowable area. When the voltage level is restored above the setting value U2 (block 8) with a time delay t2 (block 9), the load disconnected by the action of the AOSN device is again turned on under voltage (block 10). Enabling joins is performed alternately back to disconnecting.

In block 4, for each of the AOSN devices of substations 35 kV, 110 kV and 220 kV, a set of settings for voltage and time is set depending on the group of connections (see tables 2 and 3).

The reverse inclusion of connections by the action of AOSN devices is as follows:

- for a 110 kV network, when the voltage level on the controlled substation bus reaches 104.5 kV and higher (for a 35 kV network - 33.3 kV, for a 220 kV network - 209 kV), one connection from IV groups;

- then, if the voltage on the monitored busbar has not dropped below 104.5 kV, after 4 seconds the second connection from group IV is switched on;

- further, with an interval of 4 seconds, all remaining joins are turned on first of the IV group, then of the III, II and I groups;

- each subsequent switching on of the connection occurs with the control of the voltage level value on the substation bus;

- if during the process of switching on the connections the voltage on the monitored busbar drops below 104.5 kV, then the remaining connections are not switched on.

Alternate switching on of the connections is carried out to more evenly connect the load in order to prevent a repeated decrease in the voltage level on the monitored bus below the permissible values. Also, the alternate connection is carried out due to the technical impossibility of the batteries installed in the substation to enable the inclusion of several connections simultaneously. This is caused by a large total drop in the voltage level of the battery on the drives of the connection switches 6-10-20 kV and in the cables connecting the battery to the drive of the switches.

Thus, the claimed system of automatic limitation of voltage reduction allows to increase the efficiency of its work: to minimize the number of AOSN devices required for installation at substations, as well as to increase the reliability of power supply by minimizing the number of disconnected consumers of electric energy.

LITERATURE

1. Automation of limiting voltage reduction on substation tires. Utility Model Patent of the Russian Federation No. 67302, IPC G05F 1/30, 04/28/2007, publ. 10/10/2007

2. Rules for the technical operation of electrical installations of consumers. - M.: State Unitary Enterprise STC Industrial Safety, 2008. - 356 p.

3. "Guidelines for the stability of energy systems", СО 153-34.20.576-2003, approved. by order of the Ministry of Energy of Russia dated 30.06.2003 No. 277.

Claims (1)

A system for automatically limiting the voltage reduction (AOSN) in electric networks of 35-220 kV, containing the device (a) AOSN, including a unit for comparing with the disconnecting voltage, a unit for holding the time for disconnecting, a unit for sequentially disconnecting groups of connections, a unit for comparing with the voltage for connecting connections, delay time for switching on, a block for sequential switching on of individual connections, characterized in that a series-connected block for determining the modes of the electric network is introduced into the input of the system, bl ok analysis, the unit for determining the connections connected under the action of AOSN, the unit for setting the settings of the AOSN devices, and the unit for determining the modes of the electric network is made with the possibility of determining the voltage on the buses of the substations of the energy district in normal, repair and after-failure modes; the analysis unit is configured to determine substations on which it is necessary to install AOSN devices if the voltage on the tires does not exceed 0.77 of the rated voltage; the unit for determining the connections connected under the action of AOSN is configured to prioritize the connections depending on the social significance of the consumers of electric energy and the presence of an automatic reserve input (ATS) on the substation 6, 10, 20 kV buses; the unit for setting the settings of the AOSN devices is configured to set the voltage and time of disconnection and on-time taking into account the connection groups.

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