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Device for detection of synchronous vibrations source. RU patent 2508591.

IPC classes for russian patent Device for detection of synchronous vibrations source. RU patent 2508591. (RU 2508591):

H02J3/24 - Arrangements for preventing or reducing oscillations of power in networks (by control effected upon a single generator H02P0009000000)

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FIELD: electricity.

SUBSTANCE: device includes a block of correlation devices for each generator, which includes the first and the second sensors that are connected to terminals of a synchronous generator, the first and the second correlation devices determining coefficients of mutual correlation of the effective value of voltage and reactive power, the first inputs of which are connected to the output of the first sensor, the second input of the first correlation device is connected to the output of the second sensor, a time delay unit the input of which is connected to the output of the second sensor as well, and the output is connected to the second input of the second correlation device, and an analysing device to the inputs of which there connected are outputs of the first and the second correlation devices of blocks of correlation devices of all the generators; besides, a signal at the output of the analysing device appears in case one of the synchronous generators is a source of synchronous vibrations in a power system or intercomputer vibrations in the group of generators of one thermal power plant.

EFFECT: providing the possibility of detecting a source of appearance of synchronous vibrations.

2 cl, 5 dwg

The technical field

The invention relates to the measuring engineering in the power engineering and may be used in devices for monitoring the health of system controllers in a part of the automatic excitation regulators (ARV) and excitation systems (MW) at power plants and in the systems of monitoring of transient modes.

The level of technology

Development of power systems in the Russian Federation are on the path of unification on parallel work of power supply systems, power plants and large consumers of electric power located on the vast territories of the related long transmission lines, with the organization of centralized operative-dispatch control. Steady and reliable parallel operation of the Russian power systems largely depends on correct and efficient work of the HOLY and ARVs. A significant factor reducing the system reliability is the lack of operational tools for monitoring the operation of the HOLY and ARVs, which would ensure the fulfillment of the objective analysis of their work.

One of the known consequences of incorrect work of ARVs is the experience sustained synchronous low frequency in the energy system and associated with this, a possible violation of sustainability as well as machine-to-machine vibrations generators within the same power plant and, as a consequence, intragroup instability.

Known system for the analysis of low frequency containing own leakage magnetic fields dynamic early warning system and a system with man-machine interface in which data mode with synchronous oscillations of low frequency derived own leakage magnetic fields periodically transmitted in real time in a dynamic early warning system that converts the received data in the input file for the stability calculation in a small perturbation, and performs the calculation. Results are sent back in own leakage magnetic fields and further on with man-machine interface. Thus, an early warning of a possible violation of stability in case of small perturbations in the energy system at the current (measured) [1].

However, the proposed system does not allow to identify the source of low-frequency oscillations (the generator and/or a power plant), which is necessary for the adoption of the Manager of the necessary volume measures for the prevention of instability.

The essence of the invention

The technical result of the proposed technical solution is to build a device to identify the source of synchronous oscillations, i.e. determination of the generator, incorrect or ineffective channel setup stabilization of which (in the case of ARV strong action) or failure (in the case of ARV proportional type is the reason of their occurrence or development.

A device for detecting the source of synchronous oscillations contains for each generator unit correlators, containing the first and second sensors (sensor values of voltage and current sensor reactive power synchronous generator)connected to terminals synchronous generator, the first and second determining the coefficients of correlation between the current values of voltage and reactive power, the input of which is connected to the output of the first sensor, the second input of the first correlation function is connected to the second sensor, the unit delay time, the input of which is connected to the output of the second sensor, and the output is connected to the second input of the second correlator, and examines the device inputs which are connected to the outputs of the first and second correlators blocks correlators of all generators, and the output signal of analysing the devices appear in the case when one of the synchronous generator is the source of synchronous oscillations in the power system or machine-to-machine vibrations.

The claimed device does not require the use of mathematical models of energy systems, that allows to avoid mistakes and inaccuracies associated with inevitable simplifications in mathematical models and an assignment operator large amounts of input data (network structure is equivalent to the parameters of the elements and etc).

Realization of the invention

Figure 1 shows the block diagram of the proposed device for detecting the source of synchronous oscillations. To the terminals of each synchronous generator G 1-G n connected blocks correlators 1, including the first sensor 2 and the second sensor 3 the current value of voltage and reactive power of the synchronous generator. For the coefficients of correlation between the current values of voltage and reactive power introduced the first 4 and the second 6 . The device also contains a unit of time delay of 5 and analyzing device 7.

Signal at the output 7 informs that a certain analyzing device synchronous generator - source synchronous oscillations.

Sensors actual value voltage and reactive power of the synchronous generator, and block time delay are standard items of measuring equipment and systems of processing of the measuring information. Analyzing the device produces signal analysis by comparing them with each other and with the specified threshold values.

A device for detecting the source of synchronous oscillations according to the registration regime on objects of power systems of the works in the following way.

For the synchronous generator, which is the source of Electromechanical synchronous oscillations, it is typical that the fluctuations of reactive power synchronous generator Q g ahead of the phase fluctuations of the current values of voltage U g terminals of the synchronous generator or these fluctuations . Synchronous generator, which is not the source of synchronous oscillations, will prevent the arising fluctuations or fluctuations of reactive power will be determined by the fluctuations of voltage, so the fluctuations of reactive power are opposite to the fluctuations of the respective valid voltage values, or they will keep the phase.

If the above criteria is fixed at several generators within the same power plant, it indicates the emergence of this power station machine-to-machine vibrations. «Emergency generator», which is the source of machine-to-machine vibrations, among generators participating in the machine-to-machine fluctuations, characterized by minimal phase shift of synchronous oscillations Q g U g .

Known correlation method of the phase difference or amplitudes synchronously changing values [2].

When using a correlation method for estimation of the phase shift between the vibrations of low frequency reactive power and current values of voltage of the generator criterion for evaluation of the source of synchronous oscillations is the value of the coefficient of correlation between the phase-k UQ . For harmonic functions of identical frequency k UQ =cosΔφ where Δφ - oscillations phase shift Q g U g .

Cross-correlation coefficient U g Q g , calculated , is maximal and equals one when the phase shift compared fluctuations equal to zero. With the increase of the phase difference of the correlation coefficient decreases. Suppose that the current value of the voltage at the terminals of the generator is measured first sensor 2 and reactive power generator - second sensor 3. Then, if the generator - source synchronous oscillation, delay time data reactive power, the executed block 5, will reduce the phase difference between the two signals, resulting in cross-correlation coefficient calculated by the second 6 will become more similar value calculated first 4. Therefore, for the synchronous generator of the source synchronous oscillations values of the correlation coefficients calculated positive, and calculated the first is close to unity, or the value calculated by the second , more value calculated first .

Analyzing the device 7 compares the outputs of the first 4 and the second 6 correlators in the case, when the second sensor 3 measures reactive power generator, produces a signal that

generator - source synchronous fluctuations in the power system, when

- coefficient of correlation k UQ1 with the release of the first correlator exceeds the specified threshold, or,

- k UQ2 >k UQ1 , and k values UQ1 and k UQ2 positive, but less than the specified threshold of only one of the generators, or

generator - source machine-to-machine synchronous oscillations of the issues in the case when k UQ2 >k UQ1 , and k values UQ1 and k UQ2 positive, but less than the specified threshold of several generators with the indexation of the generator of the source synchronous oscillations at the maximum amount of k UQ1 among data generators.

If the second sensor measures the voltage of the synchronous generator, inequality k UQ2 >k UQ1 should be replaced by the inequality k UQ2 <k UQ1 .

Thus achieved the desired technical result reveals the source of synchronous oscillations according to the registration regime on objects of power systems.

Figure 2 shows the dynamics of instant values of voltage and reactive power of the synchronous generator (U g Q g ) in the case when the synchronous generator is the source of synchronous oscillations. On the same graph shows the coefficients of correlation k UQ1 and k UQ2 , calculated every second on the overlapping time intervals of 5 C. the Values of the correlation coefficients are close to unity.

Figure 3 presents the same parameters as in figure 2, for the case when the synchronous generator is not the source of synchronous oscillations. The relevant coefficients of correlation between the negative.

The proposed device to identify the source of synchronous oscillations were implemented in the layout developed for JSC «so UES» hardware and software complex System of monitoring of system controllers» (), which has been tested in conditions of physical model of the power system and showed the efficiency and effectiveness of the proposed technical solutions on the device.

The test scheme of the physical model of the power system, designed to test the layout of the system of monitoring of ARV and HOLY, is shown in figure 4 (a control object).

The scheme includes 6 generators with their block transformers, 6 knots complex load and 7 lines. Among other parameters in fixed Q g U g analyzer , which includes the device in question is estimated coefficient of correlation. By special configuration ARV modeled appearance in the power system of synchronous oscillations at various frequencies.

Example of defining a generator, which is the source of synchronous oscillations with increasing amplitude is shown in figure 5. Generators MG-64 (G1) and MG-47 (G2) are at the same power plant (GRES), generator MG-8 (G4) - equivalent generator NPP. Change channel settings stabilization ARV generator 1 (MG-64) leads to the release of the working settings ARV beyond the boundaries of the stability regions and the emergence of sustained synchronous oscillations. The figure shows that at the moment of detection of synchronous oscillations of the cross-correlation coefficient Q g U g vibration source (G1) is set to 1.0, that testifies to identify faulty ARVs.

Similar results were obtained in experiments in which the source of oscillations were generators G2, G4 and G6.

Sources of information

1. Patent EP 2302754(A), 2009 the State grid Company of China «Method and building a system of analysis of low frequency».

2. E., Jervis B.: Digital signal processing. A practical approach. - M, S-Petersburg, Kiev: Publishing house «Williams», 2004.

1. A device for detecting the source of synchronous oscillations containing, for each generator unit correlators, including the first and second sensors that are connected to the terminals synchronous generator, the first and second determining the coefficients of correlation between the current values of voltage and reactive power, the input of which is connected to the output of the first sensor, the second input of the first correlation function is connected to the second sensor, the unit delay time, the input of which is connected to the output of the second sensor, and the output is connected to the second input of the second correlator, and examines the device inputs which are connected to the outputs of the first and second correlators blocks correlators of all generators, and the output signal of the walking device appears in case when one of the synchronous generator is the source of synchronous oscillations in the power system or machine-to-machine fluctuations in the group generators power stations.

2. The device according to claim 1, characterized in that, as the first sensor uses a sensor current values of the voltage sensor or reactive power, as well as a second sensor using, respectively, the sensor reactive power or sensor current values of the voltage.